Highlight matching regex pattern in pager, via option `color-pager-re…

…gex`

Any line matching the regex will be drawn in a new color ↔ `color-match`.

include/tig/line.h

@@ -22,6 +22,7 @@ struct ref;
  */
 
 #define LINE_INFO(_) \
+        _(COLOR_MATCH,     ""), \
 	_(DIFF_HEADER,		"diff --"), \
 	_(DIFF_DEL_FILE,	"--- "), \
 	_(DIFF_ADD_FILE,	"+++ "), \

src/diff.c

@@ -302,12 +302,38 @@ diff_common_highlight(struct view *view, const char *text, enum line_type type)
 bool
 diff_common_read(struct view *view, const char *data, struct diff_state *state)
 {
+        const char *regex_txt;
+        regex_t regex;
+        regmatch_t pmatch[10];
+	int regex_flags = REG_EXTENDED, regex_err;
 	enum line_type type = get_line_type(data);
 
 	/* ADD2 and DEL2 are only valid in combined diff hunks */
 	if (!state->combined_diff && (type == LINE_DIFF_ADD2 || type == LINE_DIFF_DEL2))
 		type = LINE_DEFAULT;
 
+
+        if (type == LINE_DEFAULT)
+        {
+            /* Parse all compiler message lines, ie. such as:
+             *
+             * {file}:{line}:{col}: (note|warning|error):{message} 
+             *
+             */
+            if (opt_color_pager_regex != NULL && *opt_color_pager_regex)
+                regex_txt = opt_color_pager_regex;
+            else
+                /* A reasonable default - match GCC errors */
+                regex_txt = "([^:]+):([0-9]+):(|([0-9]+):)[ \t]+(note|warning|error): .*$";
+            regex_err = regcomp(&regex, regex_txt, regex_flags);
+
+            if (!regex_err)
+                regex_err = regexec(&regex, data, 8, pmatch, 0);
+
+            if (!regex_err) 
+                type = LINE_COLOR_MATCH;
+            regfree(&regex);
+        }
 	/* DEL_FILE, ADD_FILE and START are only valid outside diff chunks */
 	if (state->reading_diff_chunk) {
 		if (type == LINE_DIFF_DEL_FILE || type == LINE_DIFF_START)

tigrc

@@ -449,6 +449,7 @@ color palette-12		white	default	bold
 color palette-13		red	default	bold
 color graph-commit		blue	default
 color search-result		black	yellow
+color color-match               yellow  default bold
 
 # Mappings for colors read from git configuration.
 # Set to "no" to disable.