merge(third_party/cgit): Import at master of 2020-01-11

Imported commit '723dc8fbcb' as
'third_party/cgit'.

third_party/cgit/configfile.c

@@ -0,0 +1,90 @@
+/* configfile.c: parsing of config files
+ *
+ * Copyright (C) 2006-2014 cgit Development Team <cgit@lists.zx2c4.com>
+ *
+ * Licensed under GNU General Public License v2
+ *   (see COPYING for full license text)
+ */
+
+#include <git-compat-util.h>
+#include "configfile.h"
+
+static int next_char(FILE *f)
+{
+	int c = fgetc(f);
+	if (c == '\r') {
+		c = fgetc(f);
+		if (c != '\n') {
+			ungetc(c, f);
+			c = '\r';
+		}
+	}
+	return c;
+}
+
+static void skip_line(FILE *f)
+{
+	int c;
+
+	while ((c = next_char(f)) && c != '\n' && c != EOF)
+		;
+}
+
+static int read_config_line(FILE *f, struct strbuf *name, struct strbuf *value)
+{
+	int c = next_char(f);
+
+	strbuf_reset(name);
+	strbuf_reset(value);
+
+	/* Skip comments and preceding spaces. */
+	for(;;) {
+		if (c == EOF)
+			return 0;
+		else if (c == '#' || c == ';')
+			skip_line(f);
+		else if (!isspace(c))
+			break;
+		c = next_char(f);
+	}
+
+	/* Read variable name. */
+	while (c != '=') {
+		if (c == '\n' || c == EOF)
+			return 0;
+		strbuf_addch(name, c);
+		c = next_char(f);
+	}
+
+	/* Read variable value. */
+	c = next_char(f);
+	while (c != '\n' && c != EOF) {
+		strbuf_addch(value, c);
+		c = next_char(f);
+	}
+
+	return 1;
+}
+
+int parse_configfile(const char *filename, configfile_value_fn fn)
+{
+	static int nesting;
+	struct strbuf name = STRBUF_INIT;
+	struct strbuf value = STRBUF_INIT;
+	FILE *f;
+
+	/* cancel deeply nested include-commands */
+	if (nesting > 8)
+		return -1;
+	if (!(f = fopen(filename, "r")))
+		return -1;
+	nesting++;
+	while (read_config_line(f, &name, &value))
+		fn(name.buf, value.buf);
+	nesting--;
+	fclose(f);
+	strbuf_release(&name);
+	strbuf_release(&value);
+	return 0;
+}
+