--- /dev/null
+/*
+ * This file is part of DisOrder
+ * Copyright (C) 2008 Richard Kettlewell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+
+/** @file lib/macros-builtin.c
+ * @brief Built-in expansions
+ *
+ * This is a grab-bag of non-domain-specific expansions. Note that
+ * documentation will be generated from the comments at the head of
+ * each function.
+ */
+
+#include <config.h>
+#include "types.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <unistd.h>
+
+#include "macros.h"
+#include "sink.h"
+#include "syscalls.h"
+#include "log.h"
+#include "wstat.h"
+#include "kvp.h"
+
+/** @brief Return 1 if @p s is 'true' else 0 */
+int mx_str2bool(const char *s) {
+ return !strcmp(s, "true");
+}
+
+/** @brief Return "true" if @p n is nonzero else "false" */
+const char *mx_bool2str(int n) {
+ return n ? "true" : "false";
+}
+
+/* @include{TEMPLATE}@
+ *
+ * Includes TEMPLATE as if its text were substituted for the @include
+ * expansion. TODO
+ */
+static int exp_include(int attribute((unused)) nargs,
+ char attribute((unused)) **args,
+ struct sink attribute((unused)) *output,
+ void attribute((unused)) *u) {
+ assert(!"TODO implement search path");
+}
+
+/* @include{COMMAND}
+ *
+ * Executes COMMAND via the shell (using "sh -c") and copies its
+ * standard output to the template output. The shell command output
+ * is not expanded or modified in any other way.
+ *
+ * The shell command's standard error is copied to the error log.
+ *
+ * If the shell exits nonzero then this is reported to the error log
+ * but otherwise no special action is taken.
+ */
+static int exp_shell(int attribute((unused)) nargs,
+ char **args,
+ struct sink *output,
+ void attribute((unused)) *u) {
+ int w, p[2], n;
+ char buffer[4096];
+ pid_t pid;
+
+ xpipe(p);
+ if(!(pid = xfork())) {
+ exitfn = _exit;
+ xclose(p[0]);
+ xdup2(p[1], 1);
+ xclose(p[1]);
+ execlp("sh", "sh", "-c", args[0], (char *)0);
+ fatal(errno, "error executing sh");
+ }
+ xclose(p[1]);
+ while((n = read(p[0], buffer, sizeof buffer))) {
+ if(n < 0) {
+ if(errno == EINTR)
+ continue;
+ else
+ fatal(errno, "error reading from pipe");
+ }
+ if(output->write(output, buffer, n) < 0)
+ return -1;
+ }
+ xclose(p[0]);
+ while((n = waitpid(pid, &w, 0)) < 0 && errno == EINTR)
+ ;
+ if(n < 0)
+ fatal(errno, "error calling waitpid");
+ if(w)
+ error(0, "shell command '%s' %s", args[0], wstat(w));
+ return 0;
+}
+
+/* @if{CONDITION}{IF-TRUE}{IF-FALSE}
+ *
+ * If CONDITION is "true" then evaluates to IF-TRUE. Otherwise
+ * evaluates to IF-FALSE. The IF-FALSE part is optional.
+ */
+static int exp_if(int nargs,
+ const struct mx_node **args,
+ struct sink *output,
+ void *u) {
+ char *s;
+ int rc;
+
+ if((rc = mx_expandstr(args[0], &s, u)))
+ return rc;
+ if(mx_str2bool(s))
+ return mx_expand(args[1], output, u);
+ else if(nargs > 2)
+ return mx_expand(args[2], output, u);
+ else
+ return 0;
+}
+
+/* @and{BRANCH}{BRANCH}...
+ *
+ * Expands to "true" if all the branches are "true" otherwise to "false". If
+ * there are no brances then the result is "true". Only as many branches as
+ * necessary to compute the answer are evaluated (starting from the first one),
+ * so if later branches have side effects they may not take place.
+ */
+static int exp_and(int nargs,
+ const struct mx_node **args,
+ struct sink *output,
+ void *u) {
+ int n, result = 1, rc;
+ char *s;
+
+ for(n = 0; n < nargs; ++n) {
+ if((rc = mx_expandstr(args[n], &s, u)))
+ return rc;
+ if(!mx_str2bool(s)) {
+ result = 0;
+ break;
+ }
+ }
+ if(sink_writes(output, mx_bool2str(result)) < 0)
+ return -1;
+ else
+ return 0;
+}
+
+/* @or{BRANCH}{BRANCH}...
+ *
+ * Expands to "true" if any of the branches are "true" otherwise to "false".
+ * If there are no brances then the result is "false". Only as many branches
+ * as necessary to compute the answer are evaluated (starting from the first
+ * one), so if later branches have side effects they may not take place.
+ */
+static int exp_or(int nargs,
+ const struct mx_node **args,
+ struct sink *output,
+ void *u) {
+ int n, result = 0, rc;
+ char *s;
+
+ for(n = 0; n < nargs; ++n) {
+ if((rc = mx_expandstr(args[n], &s, u)))
+ return rc;
+ if(mx_str2bool(s)) {
+ result = 1;
+ break;
+ }
+ }
+ if(sink_writes(output, mx_bool2str(result)) < 0)
+ return -1;
+ else
+ return 0;
+}
+
+/* @not{CONDITION}
+ *
+ * Expands to "true" unless CONDITION is "true" in which case "false".
+ */
+static int exp_not(int attribute((unused)) nargs,
+ char **args,
+ struct sink *output,
+ void attribute((unused)) *u) {
+ if(sink_writes(output, mx_bool2str(!mx_str2bool(args[0]))) < 0)
+ return -1;
+ else
+ return 0;
+}
+
+/* @#{...}
+ *
+ * Expands to nothing. The argument(s) are not fully evaluated, and no side
+ * effects occur.
+ */
+static int exp_comment(int attribute((unused)) nargs,
+ const struct mx_node attribute((unused)) **args,
+ struct sink attribute((unused)) *output,
+ void attribute((unused)) *u) {
+ return 0;
+}
+
+/* @urlquote{STRING}
+ *
+ * URL-quotes a string, i.e. replaces any characters not safe to use unquoted
+ * in a URL with %-encoded form.
+ */
+static int exp_urlquote(int attribute((unused)) nargs,
+ char **args,
+ struct sink *output,
+ void attribute((unused)) *u) {
+ if(sink_writes(output, urlencodestring(args[0])) < 0)
+ return -1;
+ else
+ return 0;
+}
+
+void mx_register_builtin(void) {
+ mx_register("include", 1, 1, exp_include);
+ mx_register("shell", 1, 1, exp_shell);
+ mx_magic_register("if", 2, 3, exp_if);
+ mx_magic_register("and", 0, INT_MAX, exp_and);
+ mx_magic_register("or", 0, INT_MAX, exp_or);
+ mx_register("not", 1, 1, exp_not);
+ mx_magic_register("#", 0, INT_MAX, exp_comment);
+ mx_register("urlquote", 1, 1, exp_urlquote);
+ /* TODO: eq */
+ /* TODO: ne */
+ /* TODO: define */
+ /* TODO: discard */
+}
+
+/*
+Local Variables:
+c-basic-offset:2
+comment-column:40
+fill-column:79
+indent-tabs-mode:nil
+End:
+*/
~mdw / disorder / blobdiff