From d6dc92cc2a6ae8a6f54b90806b42ce233845ad63 Mon Sep 17 00:00:00 2001
From: Steven Luo <steven+maemo@steven676.net>
Date: Thu, 10 Dec 2009 21:15:39 -0800
Subject: [PATCH] Make config file parsing (mostly) compatible with the Python
 implementation

Redo the config file parsing using POSIX regular expressions, so that
it's mostly compatible with the Python implementation.  Full
compatibility isn't happening, of course, since the Python
implementation's config file is being sourced by the interpreter.
---
 main.c |   83 +++++++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 58 insertions(+), 25 deletions(-)

diff --git a/main.c b/main.c
index ec1a042..5429a59 100644
--- a/main.c
+++ b/main.c
@@ -27,6 +27,7 @@
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <regex.h>
 #include <dbus/dbus-glib.h>
 
 #include "browser-switchboard.h"
@@ -54,14 +55,14 @@ static void waitforzombies(int signalnum) {
 }
 
 static void read_config(int signalnum) {
-	char * homedir;
-	char * configfile;
+	char *homedir, *configfile;
 	size_t len;
 	char buf[MAXLINE];
-	char * tmp;
-	char * value;
-	char * default_browser = NULL;
-	FILE * fp;
+	char *key, *value;
+	char *default_browser = NULL;
+	FILE *fp;
+	regex_t re_ignore, re_config1, re_config2;
+	regmatch_t substrs[3];
 
 	set_config_defaults(&ctx);
 
@@ -76,36 +77,64 @@ static void read_config(int signalnum) {
 	if (!(fp = fopen(configfile, "r")))
 		goto out_noopen;
 
+	/* compile regex matching blank lines or comments */
+	if (regcomp(&re_ignore, "^[[:space:]]*(#|$)", REG_EXTENDED|REG_NOSUB))
+		goto out_nore;
+	/* compile regex matching foo = "bar", with arbitrary whitespace at
+	   beginning and end of line and surrounding the = */
+	if (regcomp(&re_config1,
+		    "^[[:space:]]*([^=[:space:]]+)[[:space:]]*=[[:space:]]*\"(.*)\"[[:space:]]*$",
+		    REG_EXTENDED)) {
+		regfree(&re_ignore);
+		goto out_nore;
+	}
+	/* compile regex matching foo = bar, with arbitrary whitespace at
+	   beginning of line and surrounding the = */
+	if (regcomp(&re_config2,
+		    "^[[:space:]]*([^=[:space:]]+)[[:space:]]*=[[:space:]]*(.*)$",
+		    REG_EXTENDED|REG_NEWLINE)) {
+		regfree(&re_ignore);
+		regfree(&re_config1);
+		goto out_nore;
+	}
+
 	/* Read in the config file one line at a time and parse it
 	   XXX doesn't deal with lines longer than MAXLINE */
 	while (fgets(buf, MAXLINE, fp)) {
-		/* skip comments */
-		if (buf[0] == '#')
+		printf("%s", buf);
+		/* skip blank lines and comments */
+		if (!regexec(&re_ignore, buf, 0, NULL, 0))
 			continue;
-		/* look for the = in the line */
-		if (!(tmp = strchr(buf, '=')))
+
+		/* Find the substrings corresponding to the key and value
+		   If the line doesn't match our idea of a config file entry,
+		   skip it */
+		if (regexec(&re_config1, buf, 3, substrs, 0) &&
+		    regexec(&re_config2, buf, 3, substrs, 0))
+			continue;
+		if (substrs[1].rm_so == -1 || substrs[2].rm_so == -1)
 			continue;
 
-		/* split the line into parameter (before =, in buf) and
-		   value (after =, in value) */
-		if (!(value = calloc(strlen(tmp+1)+1, sizeof(char))))
+		/* copy the config value into a new string */
+		len = substrs[2].rm_eo - substrs[2].rm_so;
+		if (!(value = calloc(len+1, sizeof(char))))
 			goto out;
-		strncpy(value, tmp+1, strlen(tmp+1));
-		value[strlen(tmp+1)] = '\0';
-		/* scribble over the = in buf with a \0 -- that makes buf
-		   just the parameter name */
-		*tmp = '\0';
-		/* if we find a newline in value, replace that with a \0 too */
-		if ((tmp = strchr(value, '\n')))
-			*tmp = '\0';
-
-		if (!strcmp(buf, "continuous_mode")) {
+		strncpy(value, buf+substrs[2].rm_so, len);
+		/* calloc() zeroes the memory, so string is automatically
+		   null terminated */
+
+		/* make key point to a null-terminated string holding the 
+		   config key */
+		key = buf + substrs[1].rm_so;
+		buf[substrs[1].rm_eo] = '\0';
+
+		if (!strcmp(key, "continuous_mode")) {
 			ctx.continuous_mode = atoi(value);
 			free(value);
-		} else if (!strcmp(buf, "default_browser")) {
+		} else if (!strcmp(key, "default_browser")) {
 			if (!default_browser)
 				default_browser = value;
-		} else if (!strcmp(buf, "other_browser_cmd")) {
+		} else if (!strcmp(key, "other_browser_cmd")) {
 			if (!ctx.other_browser_cmd)
 				ctx.other_browser_cmd = value;
 		} else {
@@ -120,6 +149,10 @@ static void read_config(int signalnum) {
 	printf("other_browser_cmd: '%s'\n", ctx.other_browser_cmd?ctx.other_browser_cmd:"NULL");
 
 out:
+	regfree(&re_ignore);
+	regfree(&re_config1);
+	regfree(&re_config2);
+out_nore:
 	fclose(fp);
 out_noopen:
 	update_default_browser(&ctx, default_browser);
-- 
1.7.9.5