chiark / gitweb /
tig version 0.3
[tig] / tig.c
diff --git a/tig.c b/tig.c
index 7ba1a718e031021fa4cef1fd4854a8f3089c023a..db862bf938c104ade9d2cd3bdb712460d8c4ec84 100644 (file)
--- a/tig.c
+++ b/tig.c
  * --------
  * [verse]
  * tig [options]
+ * tig [options] [--] [git log options]
  * tig [options] log  [git log options]
  * tig [options] diff [git diff options]
- * tig [options] <    [git log or git diff output]
+ * tig [options] show [git show options]
+ * tig [options] <    [git command output]
  *
  * DESCRIPTION
  * -----------
- * Browse changes in a git repository.
+ * Browse changes in a git repository. Additionally, tig(1) can also act
+ * as a pager for output of various git commands.
+ *
+ * When browsing repositories, tig(1) uses the underlying git commands
+ * to present the user with various views, such as summarized commit log
+ * and showing the commit with the log message, diffstat, and the diff.
+ *
+ * Using tig(1) as a pager, it will display input from stdin and try
+ * to colorize it.
  **/
 
-#ifndef DEBUG
-#define NDEBUG
+#ifndef        VERSION
+#define VERSION        "tig-0.3"
 #endif
 
-#ifndef        VERSION
-#define VERSION        "tig-0.1"
+#ifndef DEBUG
+#define NDEBUG
 #endif
 
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include <time.h>
 
 #include <curses.h>
 
 static void die(const char *err, ...);
 static void report(const char *msg, ...);
+static void set_nonblocking_input(bool loading);
+
+#define ABS(x)         ((x) >= 0  ? (x) : -(x))
+#define MIN(x, y)      ((x) < (y) ? (x) :  (y))
+
+#define ARRAY_SIZE(x)  (sizeof(x) / sizeof(x[0]))
+#define STRING_SIZE(x) (sizeof(x) - 1)
 
 #define SIZEOF_REF     256     /* Size of symbolic or SHA1 ID. */
 #define SIZEOF_CMD     1024    /* Size of command buffer. */
@@ -50,26 +68,25 @@ static void report(const char *msg, ...);
 /* This color name can be used to refer to the default term colors. */
 #define COLOR_DEFAULT  (-1)
 
+#define TIG_HELP       "(d)iff, (l)og, (m)ain, (q)uit, (h)elp, (Enter) show diff"
+
 /* The format and size of the date column in the main view. */
 #define DATE_FORMAT    "%Y-%m-%d %H:%M"
-#define DATE_COLS      (STRING_SIZE("2006-04-29 14:21 "))
+#define DATE_COLS      STRING_SIZE("2006-04-29 14:21 ")
 
 /* The default interval between line numbers. */
 #define NUMBER_INTERVAL        1
 
-#define        SCALE_SPLIT_VIEW(height)        ((height) * 2 / 3)
-
-#define ABS(x)         ((x) >= 0 ? (x) : -(x))
-#define MIN(x, y)      ((x) < (y) ? (x) : (y))
+#define TABSIZE                8
 
-#define ARRAY_SIZE(x)  (sizeof(x) / sizeof(x[0]))
-#define STRING_SIZE(x) (sizeof(x) - 1)
+#define        SCALE_SPLIT_VIEW(height)        ((height) * 2 / 3)
 
-/* Some ascii-shorthands that fit into the ncurses namespace. */
+/* Some ascii-shorthands fitted into the ncurses namespace. */
 #define KEY_TAB                '\t'
 #define KEY_RETURN     '\r'
 #define KEY_ESC                27
 
+
 /* User action requests. */
 enum request {
        /* Offset all requests to avoid conflicts with ncurses getch values. */
@@ -80,17 +97,23 @@ enum request {
        REQ_VIEW_DIFF,
        REQ_VIEW_LOG,
        REQ_VIEW_HELP,
+       REQ_VIEW_PAGER,
 
+       REQ_ENTER,
        REQ_QUIT,
-       REQ_SHOW_VERSION,
-       REQ_SHOW_COMMIT,
-       REQ_STOP_LOADING,
+       REQ_PROMPT,
        REQ_SCREEN_REDRAW,
+       REQ_SCREEN_RESIZE,
        REQ_SCREEN_UPDATE,
+       REQ_SHOW_VERSION,
+       REQ_STOP_LOADING,
        REQ_TOGGLE_LINE_NUMBERS,
+       REQ_VIEW_NEXT,
 
        REQ_MOVE_UP,
+       REQ_MOVE_UP_ENTER,
        REQ_MOVE_DOWN,
+       REQ_MOVE_DOWN_ENTER,
        REQ_MOVE_PAGE_UP,
        REQ_MOVE_PAGE_DOWN,
        REQ_MOVE_FIRST_LINE,
@@ -102,19 +125,32 @@ enum request {
        REQ_SCROLL_PAGE_DOWN,
 };
 
+struct ref {
+       char *name;             /* Ref name; tag or head names are shortened. */
+       char id[41];            /* Commit SHA1 ID */
+       unsigned int tag:1;     /* Is it a tag? */
+       unsigned int next:1;    /* For ref lists: are there more refs? */
+};
+
 struct commit {
        char id[41];            /* SHA1 ID. */
-       char title[75];         /* The first line of the commit message. */ 
+       char title[75];         /* The first line of the commit message. */
        char author[75];        /* The author of the commit. */
        struct tm time;         /* Date from the author ident. */
+       struct ref **refs;      /* Repository references; tags & branch heads. */
 };
 
 
+/*
+ * String helpers
+ */
+
 static inline void
 string_ncopy(char *dst, char *src, int dstlen)
 {
        strncpy(dst, src, dstlen - 1);
        dst[dstlen - 1] = 0;
+
 }
 
 /* Shorthand for safely copying into a fixed buffer. */
@@ -122,20 +158,62 @@ string_ncopy(char *dst, char *src, int dstlen)
        string_ncopy(dst, src, sizeof(dst))
 
 
+/* Shell quoting
+ *
+ * NOTE: The following is a slightly modified copy of the git project's shell
+ * quoting routines found in the quote.c file.
+ *
+ * Help to copy the thing properly quoted for the shell safety.  any single
+ * quote is replaced with '\'', any exclamation point is replaced with '\!',
+ * and the whole thing is enclosed in a
+ *
+ * E.g.
+ *  original     sq_quote     result
+ *  name     ==> name      ==> 'name'
+ *  a b      ==> a b       ==> 'a b'
+ *  a'b      ==> a'\''b    ==> 'a'\''b'
+ *  a!b      ==> a'\!'b    ==> 'a'\!'b'
+ */
+
+static size_t
+sq_quote(char buf[SIZEOF_CMD], size_t bufsize, const char *src)
+{
+       char c;
+
+#define BUFPUT(x) ( (bufsize < SIZEOF_CMD) && (buf[bufsize++] = (x)) )
+
+       BUFPUT('\'');
+       while ((c = *src++)) {
+               if (c == '\'' || c == '!') {
+                       BUFPUT('\'');
+                       BUFPUT('\\');
+                       BUFPUT(c);
+                       BUFPUT('\'');
+               } else {
+                       BUFPUT(c);
+               }
+       }
+       BUFPUT('\'');
+
+       return bufsize;
+}
+
+
 /**
  * OPTIONS
  * -------
  **/
 
-static int opt_line_number     = FALSE;
+/* Option and state variables. */
+static bool opt_line_number    = FALSE;
 static int opt_num_interval    = NUMBER_INTERVAL;
-static int opt_request         = REQ_VIEW_MAIN;
-
-char ref_head[SIZEOF_REF]      = "HEAD";
-char ref_commit[SIZEOF_REF]    = "HEAD";
+static int opt_tab_size                = TABSIZE;
+static enum request opt_request = REQ_VIEW_MAIN;
+static char opt_cmd[SIZEOF_CMD]        = "";
+static FILE *opt_pipe          = NULL;
 
 /* Returns the index of log or diff command or -1 to exit. */
-static int
+static bool
 parse_options(int argc, char *argv[])
 {
        int i;
@@ -143,40 +221,31 @@ parse_options(int argc, char *argv[])
        for (i = 1; i < argc; i++) {
                char *opt = argv[i];
 
-               /**
-                * log [options]::
-                *      git log options.
-                *
-                * diff [options]::
-                *      git diff options.
-                **/
-               if (!strcmp(opt, "log") ||
-                   !strcmp(opt, "diff")) {
-                       opt_request = opt[0] == 'l'
-                                   ? REQ_VIEW_LOG : REQ_VIEW_DIFF;
-                       return i;
-
                /**
                 * -l::
-                *      Start up in log view.
+                *      Start up in log view using the internal log command.
                 **/
-               } else if (!strcmp(opt, "-l")) {
+               if (!strcmp(opt, "-l")) {
                        opt_request = REQ_VIEW_LOG;
+                       continue;
+               }
 
                /**
                 * -d::
-                *      Start up in diff view.
+                *      Start up in diff view using the internal diff command.
                 **/
-               } else if (!strcmp(opt, "-d")) {
+               if (!strcmp(opt, "-d")) {
                        opt_request = REQ_VIEW_DIFF;
+                       continue;
+               }
 
                /**
                 * -n[INTERVAL], --line-number[=INTERVAL]::
                 *      Prefix line numbers in log and diff view.
                 *      Optionally, with interval different than each line.
                 **/
-               } else if (!strncmp(opt, "-n", 2) ||
-                          !strncmp(opt, "--line-number", 13)) {
+               if (!strncmp(opt, "-n", 2) ||
+                   !strncmp(opt, "--line-number", 13)) {
                        char *num = opt;
 
                        if (opt[1] == 'n') {
@@ -189,142 +258,181 @@ parse_options(int argc, char *argv[])
                        if (isdigit(*num))
                                opt_num_interval = atoi(num);
 
-                       opt_line_number = 1;
+                       opt_line_number = TRUE;
+                       continue;
+               }
+
+               /**
+                * -t[NSPACES], --tab-size[=NSPACES]::
+                *      Set the number of spaces tabs should be expanded to.
+                **/
+               if (!strncmp(opt, "-t", 2) ||
+                   !strncmp(opt, "--tab-size", 10)) {
+                       char *num = opt;
+
+                       if (opt[1] == 't') {
+                               num = opt + 2;
+
+                       } else if (opt[STRING_SIZE("--tab-size")] == '=') {
+                               num = opt + STRING_SIZE("--tab-size=");
+                       }
+
+                       if (isdigit(*num))
+                               opt_tab_size = MIN(atoi(num), TABSIZE);
+                       continue;
+               }
 
                /**
                 * -v, --version::
                 *      Show version and exit.
                 **/
-               } else if (!strcmp(opt, "-v") ||
-                          !strcmp(opt, "--version")) {
+               if (!strcmp(opt, "-v") ||
+                   !strcmp(opt, "--version")) {
                        printf("tig version %s\n", VERSION);
-                       return -1;
+                       return FALSE;
+               }
 
                /**
-                * ref::
-                *      Commit reference, symbolic or raw SHA1 ID.
+                * \--::
+                *      End of tig(1) options. Useful when specifying command
+                *      options for the main view. Example:
+                *
+                *              $ tig -- --since=1.month
                 **/
-               } else if (opt[0] && opt[0] != '-') {
-                       string_copy(ref_head, opt);
-                       string_copy(ref_commit, opt);
-
-               } else {
-                       die("unknown command '%s'", opt);
+               if (!strcmp(opt, "--")) {
+                       i++;
+                       break;
                }
-       }
-
-       return i;
-}
-
 
-/**
- * KEYS
- * ----
- *
- * d::
- *     diff
- * l::
- *     log
- * q::
- *     quit
- * r::
- *     redraw screen
- * s::
- *     stop all background loading
- * j::
- *     down
- * k::
- *     up
- * h, ?::
- *     help
- * v::
- *     version
- **/
+               /**
+                * log [git log options]::
+                *      Open log view using the given git log options.
+                *
+                * diff [git diff options]::
+                *      Open diff view using the given git diff options.
+                *
+                * show [git show options]::
+                *      Open diff view using the given git show options.
+                **/
+               if (!strcmp(opt, "log") ||
+                   !strcmp(opt, "diff") ||
+                   !strcmp(opt, "show")) {
+                       opt_request = opt[0] == 'l'
+                                   ? REQ_VIEW_LOG : REQ_VIEW_DIFF;
+                       break;
+               }
 
-#define HELP "(d)iff, (l)og, (m)ain, (q)uit, (v)ersion, (h)elp"
+               /**
+                * [git log options]::
+                *      tig(1) will stop the option parsing when the first
+                *      command line parameter not starting with "-" is
+                *      encountered. All options including this one will be
+                *      passed to git log when loading the main view.
+                *      This makes it possible to say:
+                *
+                *      $ tig tag-1.0..HEAD
+                **/
+               if (opt[0] && opt[0] != '-')
+                       break;
 
-struct keymap {
-       int alias;
-       int request;
-};
+               die("unknown command '%s'", opt);
+       }
 
-struct keymap keymap[] = {
-       /* Cursor navigation */
-       { KEY_UP,       REQ_MOVE_UP },
-       { 'k',          REQ_MOVE_UP },
-       { KEY_DOWN,     REQ_MOVE_DOWN },
-       { 'j',          REQ_MOVE_DOWN },
-       { KEY_HOME,     REQ_MOVE_FIRST_LINE },
-       { KEY_END,      REQ_MOVE_LAST_LINE },
-       { KEY_NPAGE,    REQ_MOVE_PAGE_DOWN },
-       { KEY_PPAGE,    REQ_MOVE_PAGE_UP },
+       if (!isatty(STDIN_FILENO)) {
+               /**
+                * Pager mode
+                * ~~~~~~~~~~
+                * If stdin is a pipe, any log or diff options will be ignored and the
+                * pager view will be opened loading data from stdin. The pager mode
+                * can be used for colorizing output from various git commands.
+                *
+                * Example on how to colorize the output of git-show(1):
+                *
+                *      $ git show | tig
+                **/
+               opt_request = REQ_VIEW_PAGER;
+               opt_pipe = stdin;
 
-       /* Scrolling */
-       { KEY_IC,       REQ_SCROLL_LINE_UP },
-       { KEY_DC,       REQ_SCROLL_LINE_DOWN },
-       { 'w',          REQ_SCROLL_PAGE_UP },
-       { 's',          REQ_SCROLL_PAGE_DOWN },
+       } else if (i < argc) {
+               size_t buf_size;
 
-       { KEY_RETURN,   REQ_SHOW_COMMIT },
+               /**
+                * Git command options
+                * ~~~~~~~~~~~~~~~~~~~
+                * All git command options specified on the command line will
+                * be passed to the given command and all will be shell quoted
+                * before they are passed to the shell.
+                *
+                * NOTE: If you specify options for the main view, you should
+                * not use the `--pretty` option as this option will be set
+                * automatically to the format expected by the main view.
+                *
+                * Example on how to open the log view and show both author and
+                * committer information:
+                *
+                *      $ tig log --pretty=fuller
+                *
+                * See the <<refspec, "Specifying revisions">> section below
+                * for an introduction to revision options supported by the git
+                * commands. For details on specific git command options, refer
+                * to the man page of the command in question.
+                **/
 
-       /* View switching */
-       { 'm',          REQ_VIEW_MAIN },
-       { 'd',          REQ_VIEW_DIFF },
-       { 'l',          REQ_VIEW_LOG },
-       { 'h',          REQ_VIEW_HELP },
+               if (opt_request == REQ_VIEW_MAIN)
+                       /* XXX: This is vulnerable to the user overriding
+                        * options required for the main view parser. */
+                       string_copy(opt_cmd, "git log --stat --pretty=raw");
+               else
+                       string_copy(opt_cmd, "git");
+               buf_size = strlen(opt_cmd);
 
-       /* Misc */
-       { KEY_ESC,      REQ_QUIT },
-       { 'q',          REQ_QUIT },
-       { 'z',          REQ_STOP_LOADING },
-       { 'v',          REQ_SHOW_VERSION },
-       { 'r',          REQ_SCREEN_REDRAW },
-       { 'n',          REQ_TOGGLE_LINE_NUMBERS },
+               while (buf_size < sizeof(opt_cmd) && i < argc) {
+                       opt_cmd[buf_size++] = ' ';
+                       buf_size = sq_quote(opt_cmd, buf_size, argv[i++]);
+               }
 
-       /* wgetch() with nodelay() enabled returns ERR when there's no input. */
-       { ERR,          REQ_SCREEN_UPDATE },
-};
+               if (buf_size >= sizeof(opt_cmd))
+                       die("command too long");
 
-static int
-get_request(int request)
-{
-       int i;
+               opt_cmd[buf_size] = 0;
 
-       for (i = 0; i < ARRAY_SIZE(keymap); i++)
-               if (keymap[i].alias == request)
-                       return keymap[i].request;
+       }
 
-       return request;
+       return TRUE;
 }
 
 
 /*
  * Line-oriented content detection.
- *
- *   Line type    String to match      Foreground      Background      Attributes
- *   ---------     ---------------      ----------      ----------      ---------- */
+ */
+
 #define LINE_INFO \
+/*   Line type    String to match      Foreground      Background      Attributes
+ *   ---------     ---------------      ----------      ----------      ---------- */ \
 /* Diff markup */ \
 LINE(DIFF,        "diff --git ",       COLOR_YELLOW,   COLOR_DEFAULT,  0), \
-LINE(INDEX,       "index ",            COLOR_BLUE,     COLOR_DEFAULT,  0), \
+LINE(DIFF_INDEX,   "index ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
 LINE(DIFF_CHUNK,   "@@",               COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
 LINE(DIFF_ADD,    "+",                 COLOR_GREEN,    COLOR_DEFAULT,  0), \
 LINE(DIFF_DEL,    "-",                 COLOR_RED,      COLOR_DEFAULT,  0), \
-LINE(DIFF_OLDMODE, "old mode ",                COLOR_YELLOW,   COLOR_DEFAULT,  0), \
-LINE(DIFF_NEWMODE, "new mode ",                COLOR_YELLOW,   COLOR_DEFAULT,  0), \
+LINE(DIFF_OLDMODE, "old file mode ",   COLOR_YELLOW,   COLOR_DEFAULT,  0), \
+LINE(DIFF_NEWMODE, "new file mode ",   COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 LINE(DIFF_COPY,           "copy ",             COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 LINE(DIFF_RENAME,  "rename ",          COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 LINE(DIFF_SIM,    "similarity ",       COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 LINE(DIFF_DISSIM,  "dissimilarity ",   COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 /* Pretty print commit header */ \
-LINE(AUTHOR,      "Author: ",          COLOR_CYAN,     COLOR_DEFAULT,  0), \
-LINE(MERGE,       "Merge: ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
-LINE(DATE,        "Date:   ",          COLOR_YELLOW,   COLOR_DEFAULT,  0), \
+LINE(PP_AUTHOR,           "Author: ",          COLOR_CYAN,     COLOR_DEFAULT,  0), \
+LINE(PP_COMMIT,           "Commit: ",          COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
+LINE(PP_MERGE,    "Merge: ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
+LINE(PP_DATE,     "Date:   ",          COLOR_YELLOW,   COLOR_DEFAULT,  0), \
+LINE(PP_ADATE,    "AuthorDate: ",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
+LINE(PP_CDATE,    "CommitDate: ",      COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 /* Raw commit header */ \
 LINE(COMMIT,      "commit ",           COLOR_GREEN,    COLOR_DEFAULT,  0), \
 LINE(PARENT,      "parent ",           COLOR_BLUE,     COLOR_DEFAULT,  0), \
 LINE(TREE,        "tree ",             COLOR_BLUE,     COLOR_DEFAULT,  0), \
-LINE(AUTHOR_IDENT, "author ",          COLOR_CYAN,     COLOR_DEFAULT,  0), \
+LINE(AUTHOR,      "author ",           COLOR_CYAN,     COLOR_DEFAULT,  0), \
 LINE(COMMITTER,           "committer ",        COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
 /* Misc */ \
 LINE(DIFF_TREE,           "diff-tree ",        COLOR_BLUE,     COLOR_DEFAULT,  0), \
@@ -333,11 +441,14 @@ LINE(SIGNOFF,        "    Signed-off-by", COLOR_YELLOW,   COLOR_DEFAULT,  0), \
 LINE(DEFAULT,     "",                  COLOR_DEFAULT,  COLOR_DEFAULT,  A_NORMAL), \
 LINE(CURSOR,      "",                  COLOR_WHITE,    COLOR_GREEN,    A_BOLD), \
 LINE(STATUS,      "",                  COLOR_GREEN,    COLOR_DEFAULT,  0), \
-LINE(TITLE,       "",                  COLOR_WHITE,    COLOR_BLUE,     0), \
+LINE(TITLE_BLUR,   "",                 COLOR_WHITE,    COLOR_BLUE,     0), \
+LINE(TITLE_FOCUS,  "",                 COLOR_WHITE,    COLOR_BLUE,     A_BOLD), \
 LINE(MAIN_DATE,    "",                 COLOR_BLUE,     COLOR_DEFAULT,  0), \
 LINE(MAIN_AUTHOR,  "",                 COLOR_GREEN,    COLOR_DEFAULT,  0), \
 LINE(MAIN_COMMIT,  "",                 COLOR_DEFAULT,  COLOR_DEFAULT,  0), \
-LINE(MAIN_DELIM,   "",                 COLOR_MAGENTA,  COLOR_DEFAULT,  0),
+LINE(MAIN_DELIM,   "",                 COLOR_MAGENTA,  COLOR_DEFAULT,  0), \
+LINE(MAIN_TAG,     "",                 COLOR_MAGENTA,  COLOR_DEFAULT,  A_BOLD), \
+LINE(MAIN_REF,     "",                 COLOR_CYAN,     COLOR_DEFAULT,  A_BOLD),
 
 enum line_type {
 #define LINE(type, line, fg, bg, attr) \
@@ -405,25 +516,138 @@ init_colors(void)
 }
 
 
-/*
- * Viewer
- */
+/**
+ * ENVIRONMENT VARIABLES
+ * ---------------------
+ * Several options related to the interface with git can be configured
+ * via environment options.
+ *
+ * Repository references
+ * ~~~~~~~~~~~~~~~~~~~~~
+ * Commits that are referenced by tags and branch heads will be marked
+ * by the reference name surrounded by '[' and ']':
+ *
+ *     2006-03-26 19:42 Petr Baudis         | [cogito-0.17.1] Cogito 0.17.1
+ *
+ * If you want to filter out certain directories under `.git/refs/`, say
+ * `tmp` you can do it by setting the following variable:
+ *
+ *     $ TIG_LS_REMOTE="git ls-remote . | sed /\/tmp\//d" tig
+ *
+ * Or set the variable permanently in your environment.
+ *
+ * TIG_LS_REMOTE::
+ *     Set command for retrieving all repository references. The command
+ *     should output data in the same format as git-ls-remote(1).
+ **/
 
-struct view {
-       char *name;
-       char *cmd;
-       char *id;
+#define TIG_LS_REMOTE \
+       "git ls-remote . 2>/dev/null"
 
-       /* Rendering */
-       int (*read)(struct view *, char *);
-       int (*draw)(struct view *, unsigned int);
-       size_t objsize;         /* Size of objects in the line index */
+/**
+ * [[view-commands]]
+ * View commands
+ * ~~~~~~~~~~~~~
+ * It is possible to alter which commands are used for the different views.
+ * If for example you prefer commits in the main view to be sorted by date
+ * and only show 500 commits, use:
+ *
+ *     $ TIG_MAIN_CMD="git log --date-order -n500 --pretty=raw %s" tig
+ *
+ * Or set the variable permanently in your environment.
+ *
+ * Notice, how `%s` is used to specify the commit reference. There can
+ * be a maximum of 5 `%s` ref specifications.
+ *
+ * TIG_DIFF_CMD::
+ *     The command used for the diff view. By default, git show is used
+ *     as a backend.
+ *
+ * TIG_LOG_CMD::
+ *     The command used for the log view. If you prefer to have both
+ *     author and committer shown in the log view be sure to pass
+ *     `--pretty=fuller` to git log.
+ *
+ * TIG_MAIN_CMD::
+ *     The command used for the main view. Note, you must always specify
+ *     the option: `--pretty=raw` since the main view parser expects to
+ *     read that format.
+ **/
+
+#define TIG_DIFF_CMD \
+       "git show --patch-with-stat --find-copies-harder -B -C %s"
+
+#define TIG_LOG_CMD    \
+       "git log --cc --stat -n100 %s"
+
+#define TIG_MAIN_CMD \
+       "git log --topo-order --stat --pretty=raw %s"
+
+/* ... silently ignore that the following are also exported. */
+
+#define TIG_HELP_CMD \
+       "man tig 2>/dev/null"
+
+#define TIG_PAGER_CMD \
+       ""
+
+/**
+ * The viewer
+ * ----------
+ *
+ * tig(1) presents various 'views' of a repository. Each view is based on output
+ * from an external command, most often 'git log', 'git diff', or 'git show'.
+ *
+ * The main view::
+ *     Is the default view, and it shows a one line summary of each commit
+ *     in the chosen list of revision. The summary includes commit date,
+ *     author, and the first line of the log message. Additionally, any
+ *     repository references, such as tags, will be shown.
+ *
+ * The log view::
+ *     Presents a more rich view of the revision log showing the whole log
+ *     message and the diffstat.
+ *
+ * The diff view::
+ *     Shows either the diff of the current working tree, that is, what
+ *     has changed since the last commit, or the commit diff complete
+ *     with log message, diffstat and diff.
+ *
+ * The pager view::
+ *     Is used for displaying both input from stdin and output from git
+ *     commands entered in the internal prompt.
+ *
+ * The help view::
+ *     Displays the information from the tig(1) man page. For the help view
+ *     to work you need to have the tig(1) man page installed.
+ **/
 
-       char cmdbuf[SIZEOF_CMD];
+struct view {
+       const char *name;       /* View name */
+       char *cmd_fmt;          /* Default command line format */
+       char *cmd_env;          /* Command line set via environment */
+       char *id;               /* Points to either of ref_{head,commit} */
+       size_t objsize;         /* Size of objects in the line index */
 
-       WINDOW *win;
-       WINDOW *title;
-       int height, width;
+       struct view_ops {
+               /* What type of content being displayed. Used in the
+                * title bar. */
+               char *type;
+               /* Draw one line; @lineno must be < view->height. */
+               bool (*draw)(struct view *view, unsigned int lineno);
+               /* Read one line; updates view->line. */
+               bool (*read)(struct view *view, char *line);
+               /* Depending on view, change display based on current line. */
+               bool (*enter)(struct view *view);
+       } *ops;
+
+       char cmd[SIZEOF_CMD];   /* Command buffer */
+       char ref[SIZEOF_REF];   /* Hovered commit reference */
+       char vid[SIZEOF_REF];   /* View ID. Set to id member when updating. */
+
+       int height, width;      /* The width and height of the main window */
+       WINDOW *win;            /* The main window */
+       WINDOW *title;          /* The title window living below the main window */
 
        /* Navigation */
        unsigned long offset;   /* Offset of the window top */
@@ -431,56 +655,42 @@ struct view {
 
        /* Buffering */
        unsigned long lines;    /* Total number of lines */
-       void **line;            /* Line index */
+       void **line;            /* Line index; each line contains user data */
+       unsigned int digits;    /* Number of digits in the lines member. */
 
        /* Loading */
        FILE *pipe;
        time_t start_time;
 };
 
-static int pager_draw(struct view *view, unsigned int lineno);
-static int pager_read(struct view *view, char *line);
-
-static int main_draw(struct view *view, unsigned int lineno);
-static int main_read(struct view *view, char *line);
+static struct view_ops pager_ops;
+static struct view_ops main_ops;
 
-static void update_title(struct view *view);
+static char ref_head[SIZEOF_REF]       = "HEAD";
+static char ref_commit[SIZEOF_REF]     = "HEAD";
 
-#define DIFF_CMD \
-       "git log --stat -n1 %s ; echo; " \
-       "git diff --find-copies-harder -B -C %s^ %s"
+#define VIEW_STR(name, cmd, env, ref, objsize, ops) \
+       { name, cmd, #env, ref, objsize, ops }
 
-#define LOG_CMD        \
-       "git log --cc --stat -n100 %s"
-
-#define MAIN_CMD \
-       "git log --stat --pretty=raw %s"
-
-#define HELP_CMD \
-       "man tig 2> /dev/null"
-
-/* The status window is used for polling keystrokes. */
-static WINDOW *status_win;
-
-/* The number of loading views. Controls when nodelay should be in effect when
- * polling user input. */
-static unsigned int nloading;
+#define VIEW_(id, name, ops, ref, objsize) \
+       VIEW_STR(name, TIG_##id##_CMD,  TIG_##id##_CMD, ref, objsize, ops)
 
 static struct view views[] = {
-       { "main",  MAIN_CMD,   ref_head,    main_read,   main_draw,  sizeof(struct commit) },
-       { "diff",  DIFF_CMD,   ref_commit,  pager_read,  pager_draw, sizeof(char) },
-       { "log",   LOG_CMD,    ref_head,    pager_read,  pager_draw, sizeof(char) },
-       { "help",  HELP_CMD,   ref_head,    pager_read,  pager_draw, sizeof(char) },
+       VIEW_(MAIN,  "main",  &main_ops,  ref_head,   sizeof(struct commit)),
+       VIEW_(DIFF,  "diff",  &pager_ops, ref_commit, sizeof(char)),
+       VIEW_(LOG,   "log",   &pager_ops, ref_head,   sizeof(char)),
+       VIEW_(HELP,  "help",  &pager_ops, ref_head,   sizeof(char)),
+       VIEW_(PAGER, "pager", &pager_ops, "static",   sizeof(char)),
 };
 
 #define VIEW(req) (&views[(req) - REQ_OFFSET - 1])
 
 /* The display array of active views and the index of the current view. */
-static struct view *display[ARRAY_SIZE(views)];
+static struct view *display[2];
 static unsigned int current_view;
 
 #define foreach_view(view, i) \
-       for (i = 0; i < sizeof(display) && (view = display[i]); i++)
+       for (i = 0; i < ARRAY_SIZE(display) && (view = display[i]); i++)
 
 
 static void
@@ -489,7 +699,7 @@ redraw_view_from(struct view *view, int lineno)
        assert(0 <= lineno && lineno < view->height);
 
        for (; lineno < view->height; lineno++) {
-               if (!view->draw(view, lineno))
+               if (!view->ops->draw(view, lineno))
                        break;
        }
 
@@ -504,41 +714,89 @@ redraw_view(struct view *view)
        redraw_view_from(view, 0);
 }
 
-static struct view *
-resize_view(struct view *view)
+static void
+resize_display(void)
 {
-       int lines, cols;
+       int offset, i;
+       struct view *base = display[0];
+       struct view *view = display[1] ? display[1] : display[0];
 
-       getmaxyx(stdscr, lines, cols);
+       /* Setup window dimensions */
 
-       if (view->win) {
-               mvwin(view->win, 0, 0);
-               wresize(view->win, lines - 2, cols);
+       getmaxyx(stdscr, base->height, base->width);
 
-       } else {
-               view->win = newwin(lines - 2, 0, 0, 0);
+       /* Make room for the status window. */
+       base->height -= 1;
+
+       if (view != base) {
+               /* Horizontal split. */
+               view->width   = base->width;
+               view->height  = SCALE_SPLIT_VIEW(base->height);
+               base->height -= view->height;
+
+               /* Make room for the title bar. */
+               view->height -= 1;
+       }
+
+       /* Make room for the title bar. */
+       base->height -= 1;
+
+       offset = 0;
+
+       foreach_view (view, i) {
+               /* Keep the size of the all view windows one lager than is
+                * required. This makes current line management easier when the
+                * cursor will go outside the window. */
                if (!view->win) {
-                       report("Failed to create %s view", view->name);
-                       return NULL;
-               }
-               scrollok(view->win, TRUE);
+                       view->win = newwin(view->height + 1, 0, offset, 0);
+                       if (!view->win)
+                               die("Failed to create %s view", view->name);
 
-               view->title = newwin(1, 0, lines - 2, 0);
-               if (!view->title) {
-                       delwin(view->win);
-                       view->win = NULL;
-                       report("Failed to create title window");
-                       return NULL;
+                       scrollok(view->win, TRUE);
+
+                       view->title = newwin(1, 0, offset + view->height, 0);
+                       if (!view->title)
+                               die("Failed to create title window");
+
+               } else {
+                       wresize(view->win, view->height + 1, view->width);
+                       mvwin(view->win,   offset, 0);
+                       mvwin(view->title, offset + view->height, 0);
+                       wrefresh(view->win);
                }
-               wbkgdset(view->title, get_line_attr(LINE_TITLE));
 
+               offset += view->height + 1;
        }
+}
+
+static void
+update_view_title(struct view *view)
+{
+       if (view == display[current_view])
+               wbkgdset(view->title, get_line_attr(LINE_TITLE_FOCUS));
+       else
+               wbkgdset(view->title, get_line_attr(LINE_TITLE_BLUR));
+
+       werase(view->title);
+       wmove(view->title, 0, 0);
 
-       getmaxyx(view->win, view->height, view->width);
+       /* [main] ref: 334b506... - commit 6 of 4383 (0%) */
 
-       return view;
-}
+       if (*view->ref)
+               wprintw(view->title, "[%s] %s", view->name, view->ref);
+       else
+               wprintw(view->title, "[%s]", view->name);
 
+       if (view->lines) {
+               wprintw(view->title, " - %s %d of %d (%d%%)",
+                       view->ops->type,
+                       view->lineno + 1,
+                       view->lines,
+                       (view->lineno + 1) * 100 / view->lines);
+       }
+
+       wrefresh(view->title);
+}
 
 /*
  * Navigation
@@ -565,7 +823,7 @@ do_scroll_view(struct view *view, int lines)
                wscrl(view->win, lines);
 
                for (; line < end; line++) {
-                       if (!view->draw(view, line))
+                       if (!view->ops->draw(view, line))
                                break;
                }
        }
@@ -573,11 +831,17 @@ do_scroll_view(struct view *view, int lines)
        /* Move current line into the view. */
        if (view->lineno < view->offset) {
                view->lineno = view->offset;
-               view->draw(view, 0);
+               view->ops->draw(view, 0);
 
        } else if (view->lineno >= view->offset + view->height) {
+               if (view->lineno == view->offset + view->height) {
+                       /* Clear the hidden line so it doesn't show if the view
+                        * is scrolled up. */
+                       wmove(view->win, view->height, 0);
+                       wclrtoeol(view->win);
+               }
                view->lineno = view->offset + view->height - 1;
-               view->draw(view, view->lineno - view->offset);
+               view->ops->draw(view, view->lineno - view->offset);
        }
 
        assert(view->offset <= view->lineno && view->lineno < view->lines);
@@ -589,7 +853,7 @@ do_scroll_view(struct view *view, int lines)
 
 /* Scroll frontend */
 static void
-scroll_view(struct view *view, int request)
+scroll_view(struct view *view, enum request request)
 {
        int lines = 1;
 
@@ -601,7 +865,7 @@ scroll_view(struct view *view, int request)
                        lines = view->lines - view->offset;
 
                if (lines == 0 || view->offset + view->height >= view->lines) {
-                       report("Already at last line");
+                       report("Cannot scroll beyond the last line");
                        return;
                }
                break;
@@ -613,12 +877,15 @@ scroll_view(struct view *view, int request)
                        lines = view->offset;
 
                if (lines == 0) {
-                       report("Already at first line");
+                       report("Cannot scroll beyond the first line");
                        return;
                }
 
                lines = -lines;
                break;
+
+       default:
+               die("request %d not handled in switch", request);
        }
 
        do_scroll_view(view, lines);
@@ -626,7 +893,7 @@ scroll_view(struct view *view, int request)
 
 /* Cursor moving */
 static void
-move_view(struct view *view, int request)
+move_view(struct view *view, enum request request)
 {
        int steps;
 
@@ -650,20 +917,25 @@ move_view(struct view *view, int request)
                break;
 
        case REQ_MOVE_UP:
+       case REQ_MOVE_UP_ENTER:
                steps = -1;
                break;
 
        case REQ_MOVE_DOWN:
+       case REQ_MOVE_DOWN_ENTER:
                steps = 1;
                break;
+
+       default:
+               die("request %d not handled in switch", request);
        }
 
        if (steps <= 0 && view->lineno == 0) {
-               report("Already at first line");
+               report("Cannot move beyond the first line");
                return;
 
-       } else if (steps >= 0 && view->lineno + 1 == view->lines) {
-               report("Already at last line");
+       } else if (steps >= 0 && view->lineno + 1 >= view->lines) {
+               report("Cannot move beyond the last line");
                return;
        }
 
@@ -677,7 +949,7 @@ move_view(struct view *view, int request)
 
                wmove(view->win, prev_lineno, 0);
                wclrtoeol(view->win);
-               view->draw(view, view->lineno - steps - view->offset);
+               view->ops->draw(view, prev_lineno);
        }
 
        /* Check whether the view needs to be scrolled */
@@ -700,7 +972,7 @@ move_view(struct view *view, int request)
        }
 
        /* Draw the current line */
-       view->draw(view, view->lineno - view->offset);
+       view->ops->draw(view, view->lineno - view->offset);
 
        redrawwin(view->win);
        wrefresh(view->win);
@@ -717,19 +989,37 @@ begin_update(struct view *view)
 {
        char *id = view->id;
 
-       if (snprintf(view->cmdbuf, sizeof(view->cmdbuf), view->cmd,
-                    id, id, id) < sizeof(view->cmdbuf))
-               view->pipe = popen(view->cmdbuf, "r");
+       if (opt_cmd[0]) {
+               string_copy(view->cmd, opt_cmd);
+               opt_cmd[0] = 0;
+               /* When running random commands, the view ref could have become
+                * invalid so clear it. */
+               view->ref[0] = 0;
+       } else {
+               char *format = view->cmd_env ? view->cmd_env : view->cmd_fmt;
+
+               if (snprintf(view->cmd, sizeof(view->cmd), format,
+                            id, id, id, id, id) >= sizeof(view->cmd))
+                       return FALSE;
+       }
+
+       /* Special case for the pager view. */
+       if (opt_pipe) {
+               view->pipe = opt_pipe;
+               opt_pipe = NULL;
+       } else {
+               view->pipe = popen(view->cmd, "r");
+       }
 
        if (!view->pipe)
                return FALSE;
 
-       if (nloading++ == 0)
-               nodelay(status_win, TRUE);
+       set_nonblocking_input(TRUE);
 
        view->offset = 0;
        view->lines  = 0;
        view->lineno = 0;
+       string_copy(view->vid, id);
 
        if (view->line) {
                int i;
@@ -750,14 +1040,17 @@ begin_update(struct view *view)
 static void
 end_update(struct view *view)
 {
-       if (nloading-- == 1)
-               nodelay(status_win, FALSE);
-
-       pclose(view->pipe);
+       if (!view->pipe)
+               return;
+       set_nonblocking_input(FALSE);
+       if (view->pipe == stdin)
+               fclose(view->pipe);
+       else
+               pclose(view->pipe);
        view->pipe = NULL;
 }
 
-static int
+static bool
 update_view(struct view *view)
 {
        char buffer[BUFSIZ];
@@ -766,7 +1059,7 @@ update_view(struct view *view)
        /* The number of lines to read. If too low it will cause too much
         * redrawing (and possible flickering), if too high responsiveness
         * will suffer. */
-       int lines = view->height;
+       unsigned long lines = view->height;
        int redraw_from = -1;
 
        if (!view->pipe)
@@ -783,21 +1076,31 @@ update_view(struct view *view)
        view->line = tmp;
 
        while ((line = fgets(buffer, sizeof(buffer), view->pipe))) {
-               int linelen;
+               int linelen = strlen(line);
 
-               linelen = strlen(line);
                if (linelen)
                        line[linelen - 1] = 0;
 
-               if (!view->read(view, line))
+               if (!view->ops->read(view, line))
                        goto alloc_error;
 
                if (lines-- == 1)
                        break;
        }
 
-       /* CPU hogilicious! */
-       update_title(view);
+       {
+               int digits;
+
+               lines = view->lines;
+               for (digits = 0; lines; digits++)
+                       lines /= 10;
+
+               /* Keep the displayed view in sync with line number scaling. */
+               if (digits != view->digits) {
+                       view->digits = digits;
+                       redraw_from = 0;
+               }
+       }
 
        if (redraw_from >= 0) {
                /* If this is an incremental update, redraw the previous line
@@ -810,15 +1113,28 @@ update_view(struct view *view)
                redraw_view_from(view, redraw_from);
        }
 
+       /* Update the title _after_ the redraw so that if the redraw picks up a
+        * commit reference in view->ref it'll be available here. */
+       update_view_title(view);
+
        if (ferror(view->pipe)) {
-               report("Failed to read %s: %s", view->cmd, strerror(errno));
+               report("Failed to read: %s", strerror(errno));
                goto end;
 
        } else if (feof(view->pipe)) {
                time_t secs = time(NULL) - view->start_time;
 
                if (view == VIEW(REQ_VIEW_HELP)) {
-                       report("%s", HELP);
+                       char *msg = TIG_HELP;
+
+                       if (view->lines == 0) {
+                               /* Slightly ugly, but abusing view->ref keeps
+                                * the error message. */
+                               string_copy(view->ref, "No help available");
+                               msg = "The tig(1) manpage is not installed";
+                       }
+
+                       report("%s", msg);
                        goto end;
                }
 
@@ -837,84 +1153,108 @@ end:
        return FALSE;
 }
 
-static struct view *
-switch_view(struct view *prev, int request)
+enum open_flags {
+       OPEN_DEFAULT = 0,       /* Use default view switching. */
+       OPEN_SPLIT = 1,         /* Split current view. */
+       OPEN_BACKGROUNDED = 2,  /* Backgrounded. */
+       OPEN_RELOAD = 4,        /* Reload view even if it is the current. */
+};
+
+static void
+open_view(struct view *prev, enum request request, enum open_flags flags)
 {
+       bool backgrounded = !!(flags & OPEN_BACKGROUNDED);
+       bool split = !!(flags & OPEN_SPLIT);
+       bool reload = !!(flags & OPEN_RELOAD);
        struct view *view = VIEW(request);
        struct view *displayed;
-       int i;
-
-       if (!view->win && !resize_view(view))
-               return prev;
-
-       if (view == prev) {
-               foreach_view (displayed, i)
-                       /* count */ ;
-
-               if (i == 1) {
-                       report("Already in %s view", view->name);
-                       return view;
+       int nviews;
+
+       /* Cycle between displayed views and count the views. */
+       foreach_view (displayed, nviews) {
+               if (prev != view &&
+                   view == displayed &&
+                   !strcmp(view->vid, prev->vid)) {
+                       current_view = nviews;
+                       /* Blur out the title of the previous view. */
+                       update_view_title(prev);
+                       report("");
+                       return;
                }
+       }
+
+       if (view == prev && nviews == 1 && !reload) {
+               report("Already in %s view", view->name);
+               return;
+       }
 
-               report("FIXME: Maximize");
-               return view;
+       if ((reload || strcmp(view->vid, view->id)) &&
+           !begin_update(view)) {
+               report("Failed to load %s view", view->name);
+               return;
+       }
 
+       if (split) {
+               display[current_view + 1] = view;
+               if (!backgrounded)
+                       current_view++;
        } else {
-               foreach_view (displayed, i) {
-                       if (view == displayed) {
-                               current_view = i;
-                               /* Blur out the title of the previous view. */
-                               update_title(prev);
-                               report("Switching to %s view", view->name);
-                               return view;
-                       }
-               }
+               /* Maximize the current view. */
+               memset(display, 0, sizeof(display));
+               current_view = 0;
+               display[current_view] = view;
+       }
 
-               /* Split to diff view */
-               if (i == 1 &&
-                   SCALE_SPLIT_VIEW(prev->height) > 3 &&
-                   prev == VIEW(REQ_VIEW_MAIN) &&
-                   view == VIEW(REQ_VIEW_DIFF)) {
-                       view->height  = SCALE_SPLIT_VIEW(prev->height) - 1;
-                       prev->height -= view->height + 1;
+       resize_display();
 
-                       wresize(prev->win, prev->height, prev->width);
-                       mvwin(prev->title, prev->height, 0);
+       if (split && prev->lineno - prev->offset >= prev->height) {
+               /* Take the title line into account. */
+               int lines = prev->lineno - prev->offset - prev->height + 1;
 
-                       wresize(view->win, view->height, view->width);
-                       mvwin(view->win,   prev->height + 1, 0);
-                       mvwin(view->title, prev->height + 1 + view->height, 0);
-                       wrefresh(view->win);
-                       current_view++;
-                       update_title(prev);
-               }
+               /* Scroll the view that was split if the current line is
+                * outside the new limited view. */
+               do_scroll_view(prev, lines);
        }
 
-       /* Continue loading split views in the background. */
-       if (prev && prev->pipe && current_view < 1)
-               end_update(prev);
+       if (prev && view != prev) {
+               /* "Blur" the previous view. */
+               if (!backgrounded)
+                       update_view_title(prev);
 
-       if (begin_update(view)) {
+               /* Continue loading split views in the background. */
+               if (!split)
+                       end_update(prev);
+       }
+
+       if (view->pipe) {
                /* Clear the old view and let the incremental updating refill
                 * the screen. */
-               display[current_view] = view;
                wclear(view->win);
                report("Loading...");
+       } else {
+               redraw_view(view);
+               if (view == VIEW(REQ_VIEW_HELP))
+                       report("%s", TIG_HELP);
+               else
+                       report("");
        }
 
-       return view;
+       /* If the view is backgrounded the above calls to report()
+        * won't redraw the view title. */
+       if (backgrounded)
+               update_view_title(view);
 }
 
 
-/* Process keystrokes */
+/*
+ * User request switch noodle
+ */
+
 static int
-view_driver(struct view *view, int key)
+view_driver(struct view *view, enum request request)
 {
-       int request = get_request(key);
        int i;
 
-       assert(view);
-
        switch (request) {
        case REQ_MOVE_UP:
        case REQ_MOVE_DOWN:
@@ -936,26 +1276,69 @@ view_driver(struct view *view, int key)
        case REQ_VIEW_DIFF:
        case REQ_VIEW_LOG:
        case REQ_VIEW_HELP:
-               view = switch_view(view, request);
+       case REQ_VIEW_PAGER:
+               open_view(view, request, OPEN_DEFAULT);
                break;
 
+       case REQ_MOVE_UP_ENTER:
+       case REQ_MOVE_DOWN_ENTER:
+               move_view(view, request);
+               /* Fall-through */
+
+       case REQ_ENTER:
+               if (!view->lines) {
+                       report("Nothing to enter");
+                       break;
+               }
+               return view->ops->enter(view);
+
+       case REQ_VIEW_NEXT:
+       {
+               int nviews = display[1] ? 2 : 1;
+               int next_view = (current_view + 1) % nviews;
+
+               if (next_view == current_view) {
+                       report("Only one view is displayed");
+                       break;
+               }
+
+               current_view = next_view;
+               /* Blur out the title of the previous view. */
+               update_view_title(view);
+               report("");
+               break;
+       }
        case REQ_TOGGLE_LINE_NUMBERS:
                opt_line_number = !opt_line_number;
                redraw_view(view);
+               update_view_title(view);
+               break;
+
+       case REQ_PROMPT:
+               /* Always reload^Wrerun commands from the prompt. */
+               open_view(view, opt_request, OPEN_RELOAD);
                break;
 
        case REQ_STOP_LOADING:
-               foreach_view (view, i)
+               foreach_view (view, i) {
                        if (view->pipe)
-                               end_update(view);
+                               report("Stopped loaded the %s view", view->name),
+                       end_update(view);
+               }
                break;
 
        case REQ_SHOW_VERSION:
                report("Version: %s", VERSION);
                return TRUE;
 
+       case REQ_SCREEN_RESIZE:
+               resize_display();
+               /* Fall-through */
        case REQ_SCREEN_REDRAW:
-               redraw_view(view);
+               foreach_view (view, i) {
+                       redraw_view(view);
+                       update_view_title(view);
+               }
                break;
 
        case REQ_SCREEN_UPDATE:
@@ -967,7 +1350,7 @@ view_driver(struct view *view, int key)
 
        default:
                /* An unknown key will show most commonly used commands. */
-               report("%s", HELP);
+               report("Unknown key, press 'h' for help");
                return TRUE;
        }
 
@@ -976,10 +1359,10 @@ view_driver(struct view *view, int key)
 
 
 /*
- * Rendering
+ * View backend handlers
  */
 
-static int
+static bool
 pager_draw(struct view *view, unsigned int lineno)
 {
        enum line_type type;
@@ -993,68 +1376,85 @@ pager_draw(struct view *view, unsigned int lineno)
        line = view->line[view->offset + lineno];
        type = get_line_type(line);
 
+       wmove(view->win, lineno, 0);
+
        if (view->offset + lineno == view->lineno) {
-               if (type == LINE_COMMIT)
-                       string_copy(ref_commit, line + 7);
+               if (type == LINE_COMMIT) {
+                       string_copy(view->ref, line + 7);
+                       string_copy(ref_commit, view->ref);
+               }
+
                type = LINE_CURSOR;
+               wchgat(view->win, -1, 0, type, NULL);
        }
 
        attr = get_line_attr(type);
        wattrset(view->win, attr);
 
        linelen = strlen(line);
-       linelen = MIN(linelen, view->width);
 
-       if (opt_line_number) {
-               unsigned int real_lineno = view->offset + lineno + 1;
-               int col = 0;
+       if (opt_line_number || opt_tab_size < TABSIZE) {
+               static char spaces[] = "                    ";
+               int col_offset = 0, col = 0;
 
-               if (real_lineno == 1 || (real_lineno % opt_num_interval) == 0)
-                       mvwprintw(view->win, lineno, 0, "%4d: ", real_lineno);
-               else
-                       mvwaddstr(view->win, lineno, 0, "    : ");
+               if (opt_line_number) {
+                       unsigned long real_lineno = view->offset + lineno + 1;
+
+                       if (real_lineno == 1 ||
+                           (real_lineno % opt_num_interval) == 0) {
+                               wprintw(view->win, "%.*d", view->digits, real_lineno);
+
+                       } else {
+                               waddnstr(view->win, spaces,
+                                        MIN(view->digits, STRING_SIZE(spaces)));
+                       }
+                       waddstr(view->win, ": ");
+                       col_offset = view->digits + 2;
+               }
+
+               while (line && col_offset + col < view->width) {
+                       int cols_max = view->width - col_offset - col;
+                       char *text = line;
+                       int cols;
 
-               while (line) {
                        if (*line == '\t') {
-                               waddnstr(view->win, "        ", 8 - (col % 8));
-                               col += 8 - (col % 8);
+                               assert(sizeof(spaces) > TABSIZE);
                                line++;
+                               text = spaces;
+                               cols = opt_tab_size - (col % opt_tab_size);
 
                        } else {
-                               char *tab = strchr(line, '\t');
-
-                               if (tab)
-                                       waddnstr(view->win, line, tab - line);
-                               else
-                                       waddstr(view->win, line);
-                               col += tab - line;
-                               line = tab;
+                               line = strchr(line, '\t');
+                               cols = line ? line - text : strlen(text);
                        }
+
+                       waddnstr(view->win, text, MIN(cols, cols_max));
+                       col += cols;
                }
-               waddstr(view->win, line);
 
        } else {
-#if 0
-               /* NOTE: Code for only highlighting the text on the cursor line.
-                * Kept since I've not yet decided whether to highlight the
-                * entire line or not. --fonseca */
-               /* No empty lines makes cursor drawing and clearing implicit. */
-               if (!*line)
-                       line = " ", linelen = 1;
-#endif
-               mvwaddnstr(view->win, lineno, 0, line, linelen);
-       }
+               int col = 0, pos = 0;
 
-       /* Paint the rest of the line if it's the cursor line. */
-       if (type == LINE_CURSOR)
-               wchgat(view->win, -1, 0, type, NULL);
+               for (; pos < linelen && col < view->width; pos++, col++)
+                       if (line[pos] == '\t')
+                               col += TABSIZE - (col % TABSIZE) - 1;
+
+               waddnstr(view->win, line, pos);
+       }
 
        return TRUE;
 }
 
-static int
+static bool
 pager_read(struct view *view, char *line)
 {
+       /* Compress empty lines in the help view. */
+       if (view == VIEW(REQ_VIEW_HELP) &&
+           !*line &&
+           view->lines &&
+           !*((char *) view->line[view->lines - 1]))
+               return TRUE;
+
        view->line[view->lines] = strdup(line);
        if (!view->line[view->lines])
                return FALSE;
@@ -1063,13 +1463,38 @@ pager_read(struct view *view, char *line)
        return TRUE;
 }
 
-static int
+static bool
+pager_enter(struct view *view)
+{
+       char *line = view->line[view->lineno];
+
+       if (get_line_type(line) == LINE_COMMIT) {
+               if (view == VIEW(REQ_VIEW_LOG))
+                       open_view(view, REQ_VIEW_DIFF, OPEN_SPLIT | OPEN_BACKGROUNDED);
+               else
+                       open_view(view, REQ_VIEW_DIFF, OPEN_DEFAULT);
+       }
+
+       return TRUE;
+}
+
+static struct view_ops pager_ops = {
+       "line",
+       pager_draw,
+       pager_read,
+       pager_enter,
+};
+
+
+static struct ref **get_refs(char *id);
+
+static bool
 main_draw(struct view *view, unsigned int lineno)
 {
        char buf[DATE_COLS + 1];
        struct commit *commit;
        enum line_type type;
-       int cols = 0;
+       int col = 0;
        size_t timelen;
 
        if (view->offset + lineno >= view->lines)
@@ -1079,44 +1504,83 @@ main_draw(struct view *view, unsigned int lineno)
        if (!*commit->author)
                return FALSE;
 
+       wmove(view->win, lineno, col);
+
        if (view->offset + lineno == view->lineno) {
-               string_copy(ref_commit, commit->id);
+               string_copy(view->ref, commit->id);
+               string_copy(ref_commit, view->ref);
                type = LINE_CURSOR;
+               wattrset(view->win, get_line_attr(type));
+               wchgat(view->win, -1, 0, type, NULL);
+
        } else {
                type = LINE_MAIN_COMMIT;
+               wattrset(view->win, get_line_attr(LINE_MAIN_DATE));
        }
 
-       wmove(view->win, lineno, cols);
-       wattrset(view->win, get_line_attr(LINE_MAIN_DATE));
-
        timelen = strftime(buf, sizeof(buf), DATE_FORMAT, &commit->time);
        waddnstr(view->win, buf, timelen);
        waddstr(view->win, " ");
 
-       cols += DATE_COLS;
-       wmove(view->win, lineno, cols);
-       wattrset(view->win, get_line_attr(LINE_MAIN_AUTHOR));
+       col += DATE_COLS;
+       wmove(view->win, lineno, col);
+       if (type != LINE_CURSOR)
+               wattrset(view->win, get_line_attr(LINE_MAIN_AUTHOR));
 
        if (strlen(commit->author) > 19) {
                waddnstr(view->win, commit->author, 18);
-               wattrset(view->win, get_line_attr(LINE_MAIN_DELIM));
+               if (type != LINE_CURSOR)
+                       wattrset(view->win, get_line_attr(LINE_MAIN_DELIM));
                waddch(view->win, '~');
        } else {
                waddstr(view->win, commit->author);
        }
 
-       cols += 20;
-       wattrset(view->win, A_NORMAL);
-       mvwaddch(view->win, lineno, cols, ACS_LTEE);
-       wattrset(view->win, get_line_attr(type));
-       mvwaddstr(view->win, lineno, cols + 2, commit->title);
-       wattrset(view->win, A_NORMAL);
+       col += 20;
+       if (type != LINE_CURSOR)
+               wattrset(view->win, A_NORMAL);
+
+       mvwaddch(view->win, lineno, col, ACS_LTEE);
+       wmove(view->win, lineno, col + 2);
+       col += 2;
+
+       if (commit->refs) {
+               size_t i = 0;
+
+               do {
+                       if (type == LINE_CURSOR)
+                               ;
+                       else if (commit->refs[i]->tag)
+                               wattrset(view->win, get_line_attr(LINE_MAIN_TAG));
+                       else
+                               wattrset(view->win, get_line_attr(LINE_MAIN_REF));
+                       waddstr(view->win, "[");
+                       waddstr(view->win, commit->refs[i]->name);
+                       waddstr(view->win, "]");
+                       if (type != LINE_CURSOR)
+                               wattrset(view->win, A_NORMAL);
+                       waddstr(view->win, " ");
+                       col += strlen(commit->refs[i]->name) + STRING_SIZE("[] ");
+               } while (commit->refs[i++]->next);
+       }
+
+       if (type != LINE_CURSOR)
+               wattrset(view->win, get_line_attr(type));
+
+       {
+               int titlelen = strlen(commit->title);
+
+               if (col + titlelen > view->width)
+                       titlelen = view->width - col;
+
+               waddnstr(view->win, commit->title, titlelen);
+       }
 
        return TRUE;
 }
 
 /* Reads git log --pretty=raw output and parses it into the commit struct. */
-static int
+static bool
 main_read(struct view *view, char *line)
 {
        enum line_type type = get_line_type(line);
@@ -1132,9 +1596,10 @@ main_read(struct view *view, char *line)
 
                view->line[view->lines++] = commit;
                string_copy(commit->id, line);
+               commit->refs = get_refs(commit->id);
                break;
 
-       case LINE_AUTHOR_IDENT:
+       case LINE_AUTHOR:
        {
                char *ident = line + STRING_SIZE("author ");
                char *end = strchr(ident, '<');
@@ -1190,8 +1655,10 @@ main_read(struct view *view, char *line)
 
                /* Require titles to start with a non-space character at the
                 * offset used by git log. */
+               /* FIXME: More gracefull handling of titles; append "..." to
+                * shortened titles, etc. */
                if (strncmp(line, "    ", 4) ||
-                   isspace(line[5]))
+                   isspace(line[4]))
                        break;
 
                string_copy(commit->title, line + 4);
@@ -1200,100 +1667,234 @@ main_read(struct view *view, char *line)
        return TRUE;
 }
 
+static bool
+main_enter(struct view *view)
+{
+       open_view(view, REQ_VIEW_DIFF, OPEN_SPLIT | OPEN_BACKGROUNDED);
+       return TRUE;
+}
 
-/*
- * Main
- */
+static struct view_ops main_ops = {
+       "commit",
+       main_draw,
+       main_read,
+       main_enter,
+};
 
-static void
-quit(int sig)
-{
-       if (status_win)
-               delwin(status_win);
-       endwin();
 
-       /* FIXME: Shutdown gracefully. */
+/**
+ * KEYS
+ * ----
+ * Below the default key bindings are shown.
+ **/
 
-       exit(0);
-}
+struct keymap {
+       int alias;
+       int request;
+};
 
-static void die(const char *err, ...)
-{
-       va_list args;
+static struct keymap keymap[] = {
+       /**
+        * View switching
+        * ~~~~~~~~~~~~~~
+        * m::
+        *      Switch to main view.
+        * d::
+        *      Switch to diff view.
+        * l::
+        *      Switch to log view.
+        * p::
+        *      Switch to pager view.
+        * h::
+        *      Show man page.
+        * Return::
+        *      If on a commit line show the commit diff. Additionally, if in
+        *      main or log view this will split the view. To open the commit
+        *      diff in full size view either use 'd' or press Return twice.
+        * Tab::
+        *      Switch to next view.
+        **/
+       { 'm',          REQ_VIEW_MAIN },
+       { 'd',          REQ_VIEW_DIFF },
+       { 'l',          REQ_VIEW_LOG },
+       { 'p',          REQ_VIEW_PAGER },
+       { 'h',          REQ_VIEW_HELP },
 
-       endwin();
+       { KEY_TAB,      REQ_VIEW_NEXT },
+       { KEY_RETURN,   REQ_ENTER },
+
+       /**
+        * Cursor navigation
+        * ~~~~~~~~~~~~~~~~~
+        * Up::
+        *      Move cursor one line up.
+        * Down::
+        *      Move cursor one line down.
+        * k::
+        *      Move cursor one line up and enter. When used in the main view
+        *      this will always show the diff of the current commit in the
+        *      split diff view.
+        * j::
+        *      Move cursor one line down and enter.
+        * PgUp::
+        *      Move cursor one page up.
+        * PgDown::
+        *      Move cursor one page down.
+        * Home::
+        *      Jump to first line.
+        * End::
+        *      Jump to last line.
+        **/
+       { KEY_UP,       REQ_MOVE_UP },
+       { KEY_DOWN,     REQ_MOVE_DOWN },
+       { 'k',          REQ_MOVE_UP_ENTER },
+       { 'j',          REQ_MOVE_DOWN_ENTER },
+       { KEY_HOME,     REQ_MOVE_FIRST_LINE },
+       { KEY_END,      REQ_MOVE_LAST_LINE },
+       { KEY_NPAGE,    REQ_MOVE_PAGE_DOWN },
+       { KEY_PPAGE,    REQ_MOVE_PAGE_UP },
 
-       va_start(args, err);
-       fputs("tig: ", stderr);
-       vfprintf(stderr, err, args);
-       fputs("\n", stderr);
-       va_end(args);
+       /**
+        * Scrolling
+        * ~~~~~~~~~
+        * Insert::
+        *      Scroll view one line up.
+        * Delete::
+        *      Scroll view one line down.
+        * w::
+        *      Scroll view one page up.
+        * s::
+        *      Scroll view one page down.
+        **/
+       { KEY_IC,       REQ_SCROLL_LINE_UP },
+       { KEY_DC,       REQ_SCROLL_LINE_DOWN },
+       { 'w',          REQ_SCROLL_PAGE_UP },
+       { 's',          REQ_SCROLL_PAGE_DOWN },
 
-       exit(1);
-}
+       /**
+        * Misc
+        * ~~~~
+        * q::
+        *      Quit
+        * r::
+        *      Redraw screen.
+        * z::
+        *      Stop all background loading. This can be useful if you use
+        *      tig(1) in a repository with a long history without limiting
+        *      the revision log.
+        * v::
+        *      Show version.
+        * n::
+        *      Toggle line numbers on/off.
+        * ':'::
+        *      Open prompt. This allows you to specify what git command
+        *      to run. Example:
+        *
+        *      :log -p
+        **/
+       { 'q',          REQ_QUIT },
+       { 'z',          REQ_STOP_LOADING },
+       { 'v',          REQ_SHOW_VERSION },
+       { 'r',          REQ_SCREEN_REDRAW },
+       { 'n',          REQ_TOGGLE_LINE_NUMBERS },
+       { ':',          REQ_PROMPT },
 
-static void
-update_title(struct view *view)
-{
-       werase(view->title);
-       wmove(view->title, 0, 0);
+       /* wgetch() with nodelay() enabled returns ERR when there's no input. */
+       { ERR,          REQ_SCREEN_UPDATE },
 
-       if (view == &views[current_view])
-               wattrset(view->title, A_BOLD);
-       else
-               wattrset(view->title, A_NORMAL);
+       /* Use the ncurses SIGWINCH handler. */
+       { KEY_RESIZE,   REQ_SCREEN_RESIZE },
+};
 
-       /* [main] ref: 334b506... - line 6 of 4383 (0%) */
-       wprintw(view->title, "[%s] ref: %s", view->name, ref_commit);
-       if (view->lines) {
-               wprintw(view->title, " - line %d of %d (%d%%)",
-                       view->lineno + 1,
-                       view->lines,
-                       (view->lineno + 1) * 100 / view->lines);
-       }
+static enum request
+get_request(int key)
+{
+       int i;
 
-       wrefresh(view->title);
+       for (i = 0; i < ARRAY_SIZE(keymap); i++)
+               if (keymap[i].alias == key)
+                       return keymap[i].request;
+
+       return (enum request) key;
 }
 
+
+/*
+ * Status management
+ */
+
+/* Whether or not the curses interface has been initialized. */
+bool cursed = FALSE;
+
+/* The status window is used for polling keystrokes. */
+static WINDOW *status_win;
+
 /* Update status and title window. */
 static void
 report(const char *msg, ...)
 {
-       va_list args;
+       static bool empty = TRUE;
+       struct view *view = display[current_view];
+
+       if (!empty || *msg) {
+               va_list args;
+
+               va_start(args, msg);
 
-       va_start(args, msg);
+               werase(status_win);
+               wmove(status_win, 0, 0);
+               if (*msg) {
+                       vwprintw(status_win, msg, args);
+                       empty = FALSE;
+               } else {
+                       empty = TRUE;
+               }
+               wrefresh(status_win);
 
-       /* Update the title window first, so the cursor ends up in the status
-        * window. */
-       update_title(display[current_view]);
+               va_end(args);
+       }
 
-       werase(status_win);
-       wmove(status_win, 0, 0);
-       vwprintw(status_win, msg, args);
-       wrefresh(status_win);
+       update_view_title(view);
 
-       va_end(args);
+       /* Move the cursor to the right-most column of the cursor line.
+        *
+        * XXX: This could turn out to be a bit expensive, but it ensures that
+        * the cursor does not jump around. */
+       if (view->lines) {
+               wmove(view->win, view->lineno - view->offset, view->width - 1);
+               wrefresh(view->win);
+       }
 }
 
-int
-main(int argc, char *argv[])
+/* Controls when nodelay should be in effect when polling user input. */
+static void
+set_nonblocking_input(bool loading)
+{
+       static unsigned int loading_views;
+
+       if ((loading == FALSE && loading_views-- == 1) ||
+           (loading == TRUE  && loading_views++ == 0))
+               nodelay(status_win, loading);
+}
+
+static void
+init_display(void)
 {
        int x, y;
-       int request;
-       int git_cmd;
 
-       signal(SIGINT, quit);
+       /* Initialize the curses library */
+       if (isatty(STDIN_FILENO)) {
+               cursed = !!initscr();
+       } else {
+               /* Leave stdin and stdout alone when acting as a pager. */
+               FILE *io = fopen("/dev/tty", "r+");
 
-       git_cmd = parse_options(argc, argv);
-       if (git_cmd < 0)
-               return 0;
-       if (git_cmd < argc) {
-               die("Too many options");
+               cursed = !!newterm(NULL, io, io);
        }
 
-       request = opt_request;
+       if (!cursed)
+               die("Failed to initialize curses");
 
-       initscr();      /* Initialize the curses library */
        nonl();         /* Tell curses not to do NL->CR/NL on output */
        cbreak();       /* Take input chars one at a time, no wait for \n */
        noecho();       /* Don't echo input */
@@ -1310,26 +1911,219 @@ main(int argc, char *argv[])
        /* Enable keyboard mapping */
        keypad(status_win, TRUE);
        wbkgdset(status_win, get_line_attr(LINE_STATUS));
+}
+
+
+/*
+ * Repository references
+ */
+
+static struct ref *refs;
+static size_t refs_size;
+
+static struct ref **
+get_refs(char *id)
+{
+       struct ref **id_refs = NULL;
+       size_t id_refs_size = 0;
+       size_t i;
+
+       for (i = 0; i < refs_size; i++) {
+               struct ref **tmp;
+
+               if (strcmp(id, refs[i].id))
+                       continue;
+
+               tmp = realloc(id_refs, (id_refs_size + 1) * sizeof(*id_refs));
+               if (!tmp) {
+                       if (id_refs)
+                               free(id_refs);
+                       return NULL;
+               }
+
+               id_refs = tmp;
+               if (id_refs_size > 0)
+                       id_refs[id_refs_size - 1]->next = 1;
+               id_refs[id_refs_size] = &refs[i];
+
+               /* XXX: The properties of the commit chains ensures that we can
+                * safely modify the shared ref. The repo references will
+                * always be similar for the same id. */
+               id_refs[id_refs_size]->next = 0;
+               id_refs_size++;
+       }
+
+       return id_refs;
+}
+
+static int
+load_refs(void)
+{
+       char *cmd_env = getenv("TIG_LS_REMOTE");
+       char *cmd = cmd_env && *cmd_env ? cmd_env : TIG_LS_REMOTE;
+       FILE *pipe = popen(cmd, "r");
+       char buffer[BUFSIZ];
+       char *line;
+
+       if (!pipe)
+               return ERR;
+
+       while ((line = fgets(buffer, sizeof(buffer), pipe))) {
+               char *name = strchr(line, '\t');
+               struct ref *ref;
+               int namelen;
+               bool tag = FALSE;
+               bool tag_commit = FALSE;
+
+               if (!name)
+                       continue;
+
+               *name++ = 0;
+               namelen = strlen(name) - 1;
+
+               /* Commits referenced by tags has "^{}" appended. */
+               if (name[namelen - 1] == '}') {
+                       while (namelen > 0 && name[namelen] != '^')
+                               namelen--;
+                       if (namelen > 0)
+                               tag_commit = TRUE;
+               }
+               name[namelen] = 0;
+
+               if (!strncmp(name, "refs/tags/", STRING_SIZE("refs/tags/"))) {
+                       if (!tag_commit)
+                               continue;
+                       name += STRING_SIZE("refs/tags/");
+                       tag = TRUE;
+
+               } else if (!strncmp(name, "refs/heads/", STRING_SIZE("refs/heads/"))) {
+                       name += STRING_SIZE("refs/heads/");
+
+               } else if (!strcmp(name, "HEAD")) {
+                       continue;
+               }
+
+               refs = realloc(refs, sizeof(*refs) * (refs_size + 1));
+               if (!refs)
+                       return ERR;
+
+               ref = &refs[refs_size++];
+               ref->tag = tag;
+               ref->name = strdup(name);
+               if (!ref->name)
+                       return ERR;
+
+               string_copy(ref->id, line);
+       }
+
+       if (ferror(pipe))
+               return ERR;
+
+       pclose(pipe);
+
+       if (refs_size == 0)
+               die("Not a git repository");
+
+       return OK;
+}
+
+/*
+ * Main
+ */
+
+static void
+quit(int sig)
+{
+       /* XXX: Restore tty modes and let the OS cleanup the rest! */
+       if (cursed)
+               endwin();
+       exit(0);
+}
+
+static void die(const char *err, ...)
+{
+       va_list args;
+
+       endwin();
+
+       va_start(args, err);
+       fputs("tig: ", stderr);
+       vfprintf(stderr, err, args);
+       fputs("\n", stderr);
+       va_end(args);
+
+       exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+       struct view *view;
+       enum request request;
+       size_t i;
+
+       signal(SIGINT, quit);
+
+       if (!parse_options(argc, argv))
+               return 0;
+
+       if (load_refs() == ERR)
+               die("Failed to load refs.");
+
+       for (i = 0; i < ARRAY_SIZE(views) && (view = &views[i]); i++)
+               view->cmd_env = getenv(view->cmd_env);
+
+       request = opt_request;
+
+       init_display();
 
        while (view_driver(display[current_view], request)) {
-               struct view *view;
+               int key;
                int i;
 
-               foreach_view (view, i) {
-                       if (view->pipe) {
-                               update_view(view);
-                       }
-               }
+               foreach_view (view, i)
+                       update_view(view);
 
                /* Refresh, accept single keystroke of input */
-               request = wgetch(status_win);
-               if (request == KEY_RESIZE) {
-                       int lines, cols;
+               key = wgetch(status_win);
+               request = get_request(key);
+
+               /* Some low-level request handling. This keeps access to
+                * status_win restricted. */
+               switch (request) {
+               case REQ_PROMPT:
+                       report(":");
+                       /* Temporarily switch to line-oriented and echoed
+                        * input. */
+                       nocbreak();
+                       echo();
+
+                       if (wgetnstr(status_win, opt_cmd + 4, sizeof(opt_cmd) - 4) == OK) {
+                               memcpy(opt_cmd, "git ", 4);
+                               opt_request = REQ_VIEW_PAGER;
+                       } else {
+                               request = ERR;
+                       }
 
-                       getmaxyx(stdscr, lines, cols);
+                       noecho();
+                       cbreak();
+                       break;
+
+               case REQ_SCREEN_RESIZE:
+               {
+                       int height, width;
+
+                       getmaxyx(stdscr, height, width);
 
-                       mvwin(status_win, lines - 1, 0);
-                       wresize(status_win, 1, cols - 1);
+                       /* Resize the status view and let the view driver take
+                        * care of resizing the displayed views. */
+                       wresize(status_win, 1, width);
+                       mvwin(status_win, height - 1, 0);
+                       wrefresh(status_win);
+                       break;
+               }
+               default:
+                       break;
                }
        }
 
@@ -1339,24 +2133,114 @@ main(int argc, char *argv[])
 }
 
 /**
- * TODO
- * ----
- * Features that should be explored.
+ * [[refspec]]
+ * Revision specification
+ * ----------------------
+ * This section describes various ways to specify what revisions to display
+ * or otherwise limit the view to. tig(1) does not itself parse the described
+ * revision options so refer to the relevant git man pages for futher
+ * information. Relevant man pages besides git-log(1) are git-diff(1) and
+ * git-rev-list(1).
+ *
+ * You can tune the interaction with git by making use of the options
+ * explained in this section. For example, by configuring the environment
+ * variables described in the  <<view-commands, "View commands">> section.
+ *
+ * Limit by path name
+ * ~~~~~~~~~~~~~~~~~~
+ * If you are interested only in those revisions that made changes to a
+ * specific file (or even several files) list the files like this:
+ *
+ *     $ tig log Makefile
+ *
+ * To avoid ambiguity with repository references such as tag name, be sure
+ * to separate file names from other git options using "\--". So if you
+ * have a file named 'master' it will clash with the reference named
+ * 'master', and thus you will have to use:
+ *
+ *     $ tig log -- master
+ *
+ * NOTE: For the main view, avoiding ambiguity will in some cases require
+ * you to specify two "\--" options. The first will make tig(1) stop
+ * option processing and the latter will be passed to git log.
  *
- * - Dynamic scaling of line number indentation.
+ * Limit by date or number
+ * ~~~~~~~~~~~~~~~~~~~~~~~
+ * To speed up interaction with git, you can limit the amount of commits
+ * to show both for the log and main view. Either limit by date using
+ * e.g. `--since=1.month` or limit by the number of commits using `-n400`.
  *
- * - Proper command line handling; ability to take the command that should be
- *   shown. Example:
+ * If you are only interested in changed that happened between two dates
+ * you can use:
  *
- *     $ tig log -p
+ *     $ tig -- --after=May.5th --before=2006-05-16.15:44
  *
- * - Internal command line (exmode-inspired) which allows to specify what git
- *   log or git diff command to run. Example:
+ * NOTE: The dot (".") is used as a separator instead of a space to avoid
+ * having to quote the option value. If you prefer use `--after="May 5th"`
+ * instead of `--after="May 5th"`.
  *
- *     :log -p
+ * Limiting by commit ranges
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Alternatively, commits can be limited to a specific range, such as
+ * "all commits between 'tag-1.0' and 'tag-2.0'". For example:
+ *
+ *     $ tig log tag-1.0..tag-2.0
+ *
+ * This way of commit limiting makes it trivial to only browse the commits
+ * which haven't been pushed to a remote branch. Assuming 'origin' is your
+ * upstream remote branch, using:
+ *
+ *     $ tig log origin..HEAD
+ *
+ * will list what will be pushed to the remote branch. Optionally, the ending
+ * 'HEAD' can be left out since it is implied.
+ *
+ * Limiting by reachability
+ * ~~~~~~~~~~~~~~~~~~~~~~~~
+ * Git interprets the range specifier "tag-1.0..tag-2.0" as
+ * "all commits reachable from 'tag-2.0' but not from 'tag-1.0'".
+ * Where reachability refers to what commits are ancestors (or part of the
+ * history) of the branch or tagged revision in question.
+ *
+ * If you prefer to specify which commit to preview in this way use the
+ * following:
+ *
+ *     $ tig log tag-2.0 ^tag-1.0
+ *
+ * You can think of '^' as a negation operator. Using this alternate syntax,
+ * it is possible to further prune commits by specifying multiple branch
+ * cut offs.
+ *
+ * Combining revisions specification
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Revisions options can to some degree be combined, which makes it possible
+ * to say "show at most 20 commits from within the last month that changed
+ * files under the Documentation/ directory."
+ *
+ *     $ tig -- --since=1.month -n20 -- Documentation/
+ *
+ * Examining all repository references
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * In some cases, it can be useful to query changes across all references
+ * in a repository. An example is to ask "did any line of development in
+ * this repository change a particular file within the last week". This
+ * can be accomplished using:
+ *
+ *     $ tig -- --all --since=1.week -- Makefile
+ *
+ * BUGS
+ * ----
+ * Known bugs and problems:
+ *
+ * - If the screen width is very small the main view can draw
+ *   outside the current view causing bad wrapping. Same goes
+ *   for title and status windows.
+ *
+ * TODO
+ * ----
+ * Features that should be explored.
  *
- * - Proper resizing support. I am yet to figure out whether catching SIGWINCH
- *   is preferred over using ncurses' built-in support for resizing.
+ * - Searching.
  *
  * - Locale support.
  *