#include "hash.h"
#include "sink.h"
#include "syscalls.h"
+#include "printf.h"
VECTOR_TYPE(mx_node_vector, const struct mx_node *, xrealloc);
/** @brief Maximum permitted arguments */
int max;
- /** @brief Flags */
+ /** @brief Flags
+ *
+ * See:
+ * - @ref EXP_SIMPLE
+ * - @ref EXP_MAGIC
+ * - @ref EXP_MACRO
+ * - @ref EXP_TYPE_MASK
+ */
unsigned flags;
- /** @brief Callback (cast to appropriate type) */
+ /** @brief Macro argument names */
+ char **args;
+
+ /** @brief Callback (cast to appropriate type)
+ *
+ * Cast to @ref mx_simple_callback or @ref mx_magic_callback as required. */
void (*callback)();
+
+ /** @brief Macro definition
+ *
+ * Only for @ref EXP_MACRO expansions. */
+ const struct mx_node *definition;
};
-/** @brief Expansion takes parsed templates, not strings */
+/** @brief Expansion takes pre-expanded strings
+ *
+ * @p callback is cast to @ref mx_simple_callback. */
+#define EXP_SIMPLE 0x0000
+
+/** @brief Expansion takes parsed templates, not strings
+ *
+ * @p callback is cast to @ref mx_magic_callback. The callback must do its own
+ * expansion e.g. via mx_expandstr() where necessary. */
#define EXP_MAGIC 0x0001
+/** @brief Expansion is a macro */
+#define EXP_MACRO 0x0002
+
+/** @brief Mask of types */
+#define EXP_TYPE_MASK 0x0003
+
+/** @brief Hash of all expansions
+ *
+ * Created by mx_register(), mx_register_macro() or mx_register_magic().
+ */
static hash *expansions;
+static int mx__expand_macro(const struct expansion *e,
+ const struct mx_node *m,
+ struct sink *output,
+ void *u);
+
/* Parsing ------------------------------------------------------------------ */
/** @brief Parse a template
/* Expansion registration --------------------------------------------------- */
-static void mx__register(unsigned flags,
- const char *name,
- int min,
- int max,
- void (*callback)()) {
+static int mx__register(unsigned flags,
+ const char *name,
+ int min,
+ int max,
+ char **args,
+ void (*callback)(),
+ const struct mx_node *definition) {
struct expansion e[1];
if(!expansions)
e->min = min;
e->max = max;
e->flags = flags;
+ e->args = args;
e->callback = callback;
- hash_add(expansions, name, &e, HASH_INSERT_OR_REPLACE);
+ e->definition = definition;
+ return hash_add(expansions, name, &e,
+ ((flags & EXP_TYPE_MASK) == EXP_MACRO)
+ ? HASH_INSERT : HASH_INSERT_OR_REPLACE);
}
/** @brief Register a simple expansion rule
int min,
int max,
mx_simple_callback *callback) {
- mx__register(0, name, min, max, (void (*)())callback);
+ mx__register(EXP_SIMPLE, name, min, max, 0, (void (*)())callback, 0);
}
/** @brief Register a magic expansion rule
* @param max Maximum number of arguments
* @param callback Callback to write output
*/
-void mx_magic_register(const char *name,
+void mx_register_magic(const char *name,
int min,
int max,
mx_magic_callback *callback) {
- mx__register(EXP_MAGIC, name, min, max, (void (*)())callback);
+ mx__register(EXP_MAGIC, name, min, max, 0, (void (*)())callback, 0);
+}
+
+/** @brief Register a macro
+ * @param name Name
+ * @param nargs Number of arguments
+ * @param args Argument names
+ * @param definition Macro definition
+ * @return 0 on success, negative on error
+ */
+int mx_register_macro(const char *name,
+ int nargs,
+ char **args,
+ const struct mx_node *definition) {
+ if(mx__register(EXP_MACRO, name, nargs, nargs, args, 0/*callback*/,
+ definition)) {
+ /* This locates the error to the definition, which may be a line or two
+ * beyond the @define command itself. The backtrace generated by
+ * mx_expand() may help more. */
+ error(0, "%s:%d: duplicate definition of '%s'",
+ definition->filename, definition->line, name);
+ return -2;
+ }
+ return 0;
}
/* Expansion ---------------------------------------------------------------- */
* @param m Where to start
* @param output Where to send output
* @param u User data
- * @return 0 on success, non-0 on error∑
+ * @return 0 on success, non-0 on error
+ *
+ * Interpretation of return values:
+ * - 0 means success
+ * - -1 means an error writing to the sink.
+ * - other negative values mean errors generated from with the macro
+ * expansion system
+ * - positive values are reserved for the application
*
- * If a sink write fails then -1 is returned. If any callback returns non-zero
- * then that value is returned. It is suggested that callbacks adopt this
- * policy too and use positive values to mean other kinds of fatal error.
+ * If any callback returns non-zero then that value is returned, abandoning
+ * further expansion.
*/
int mx_expand(const struct mx_node *m,
struct sink *output,
return -1;
break;
case MX_EXPANSION:
+ rc = 0;
if(!(e = hash_find(expansions, m->name))) {
error(0, "%s:%d: unknown expansion name '%s'",
m->filename, m->line, m->name);
m->filename, m->line, m->name, e->max, m->nargs);
if(sink_printf(output, "[[%s too many args]]", m->name) < 0)
return -1;
- } else if(e->flags & EXP_MAGIC) {
- /* Magic callbacks we can call directly */
- if((rc = ((mx_magic_callback *)e->callback)(m->nargs,
- m->args,
- output,
- u)))
- return rc;
- } else {
- /* For simple callbacks we expand their arguments for them */
- char **args = xcalloc(1 + m->nargs, sizeof (char *));
- int n;
-
- for(n = 0; n < m->nargs; ++n)
- if((rc = mx_expandstr(m->args[n], &args[n], u)))
- return rc;
- args[n] = NULL;
- if((rc = ((mx_simple_callback *)e->callback)(m->nargs,
+ } else switch(e->flags & EXP_TYPE_MASK) {
+ case EXP_MAGIC: {
+ /* Magic callbacks we can call directly */
+ rc = ((mx_magic_callback *)e->callback)(m->nargs,
+ m->args,
+ output,
+ u);
+ break;
+ }
+ case EXP_SIMPLE: {
+ /* For simple callbacks we expand their arguments for them. */
+ char **args = xcalloc(1 + m->nargs, sizeof (char *)), *argname;
+ int n;
+
+ for(n = 0; n < m->nargs; ++n) {
+ /* Argument numbers are at least clear from looking at the text;
+ * adding names as well would be nice. TODO */
+ byte_xasprintf(&argname, "argument #%d", n);
+ if((rc = mx_expandstr(m->args[n], &args[n], u, argname)))
+ break;
+ }
+ if(!rc) {
+ args[n] = NULL;
+ rc = ((mx_simple_callback *)e->callback)(m->nargs,
args,
output,
- u)))
- return rc;
+ u);
+ }
+ break;
+ }
+ case EXP_MACRO: {
+ /* Macros we expand by rewriting their definition with argument values
+ * substituted and then expanding that. */
+ rc = mx__expand_macro(e, m, output, u);
+ break;
+ }
+ default:
+ assert(!"impossible EXP_TYPE_MASK value");
+ }
+ if(rc) {
+ /* For non-IO errors we generate some backtrace */
+ if(rc != -1)
+ error(0, " ...in '%s' at %s:%d",
+ m->name, m->filename, m->line);
+ return rc;
}
break;
default:
assert(!"invalid m->type");
}
- return mx_expand(m, output, u);
+ return mx_expand(m->next, output, u);
}
/** @brief Expand a template storing the result in a string
* @param m Where to start
* @param sp Where to store string
* @param u User data
+ * @param what Token for backtrace, or NULL
* @return 0 on success, non-0 on error
*
* Same return conventions as mx_expand(). This wrapper is slightly more
*/
int mx_expandstr(const struct mx_node *m,
char **sp,
- void *u) {
+ void *u,
+ const char *what) {
struct dynstr d[1];
int rc;
+ dynstr_init(d);
if(!(rc = mx_expand(m, sink_dynstr(d), u))) {
dynstr_terminate(d);
*sp = d->vec;
- }
+ } else
+ *sp = 0;
+ if(rc && rc != -1 && what)
+ error(0, " ...in %s at %s:%d", what, m->filename, m->line);
return rc;
}
int mx_expand_file(const char *path,
struct sink *output,
void *u) {
- int fd, n;
+ int fd, n, rc;
struct stat sb;
char *b;
off_t sofar;
+ const struct mx_node *m;
if((fd = open(path, O_RDONLY)) < 0)
fatal(errno, "error opening %s", path);
fatal(errno, "error reading %s", path);
}
xclose(fd);
- return mx_expand(mx_parse(path, 1, b, b + sb.st_size),
- output,
- u);
+ m = mx_parse(path, 1, b, b + sb.st_size);
+ rc = mx_expand(m, output, u);
+ if(rc && rc != -1)
+ /* Mention inclusion in backtrace */
+ error(0, " ...in inclusion of file '%s'", path);
+ return rc;
+}
+
+/** @brief Rewrite a parse tree substituting in macro arguments
+ * @param m Parse tree to rewrite (from macro definition)
+ * @param h Hash mapping argument names to argument values
+ * @return Rewritten parse tree
+ */
+static const struct mx_node *mx__rewrite(const struct mx_node *m,
+ hash *h) {
+ const struct mx_node *head = 0, **tailp = &head, *arg, *mm;
+ struct mx_node *nm;
+ int n;
+
+ for(; m; m = m->next) {
+ switch(m->type) {
+ case MX_TEXT:
+ nm = xmalloc(sizeof *nm);
+ *nm = *m; /* Dumb copy of text node fields */
+ nm->next = 0; /* Maintain list structure */
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ break;
+ case MX_EXPANSION:
+ if(m->nargs == 0
+ && (arg = hash_find(h, m->name))) {
+ /* This expansion has no arguments and its name matches one of the
+ * macro arguments. (Even if it's a valid expansion name we override
+ * it.) We insert its value at this point. We do NOT recursively
+ * rewrite the argument's value - it is outside the lexical scope of
+ * the argument name.
+ *
+ * We need to recreate the list structure but a shallow copy will
+ * suffice here.
+ */
+ for(mm = arg; mm; mm = mm->next) {
+ nm = xmalloc(sizeof *nm);
+ *nm = *mm;
+ nm->next = 0;
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ }
+ } else {
+ /* This is some other expansion. We recursively rewrite its argument
+ * values according to h. */
+ nm = xmalloc(sizeof *nm);
+ *nm = *mm;
+ for(n = 0; n < nm->nargs; ++n)
+ nm->args[n] = mx__rewrite(m->args[n], h);
+ nm->next = 0;
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ }
+ break;
+ default:
+ assert(!"invalid m->type");
+ }
+ }
+ *tailp = 0; /* Mark end of list */
+ return head;
+}
+
+/** @brief Expand a macro
+ * @param e Macro definition
+ * @param m Macro expansion
+ * @param output Where to send output
+ * @param u User data
+ * @return 0 on success, non-0 on error
+ */
+static int mx__expand_macro(const struct expansion *e,
+ const struct mx_node *m,
+ struct sink *output,
+ void *u) {
+ hash *h = hash_new(sizeof (struct mx_node *));
+ int n;
+
+ /* We store the macro arguments in a hash. Currently there is no check for
+ * duplicate argument names (and this would be the wrong place for it
+ * anyway); if you do that you just lose in some undefined way. */
+ for(n = 0; n < m->nargs; ++n)
+ hash_add(h, e->args[n], m->args[n], HASH_INSERT);
+ /* Generate a rewritten parse tree */
+ m = mx__rewrite(e->definition, h);
+ /* Expand the result */
+ return mx_expand(m, output, u);
+ /* mx_expand() will update the backtrace */
}
/*
~mdw / disorder / blobdiff