From: Gabriel Scherer <gabriel.scherer@gmail.com>
Date: Sun, 10 Jun 2018 10:53:04 +0000 (+0200)
Subject: New command-line option -k/--get-config prints the value of a config key
X-Git-Tag: v3.5~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e67eb20f518a9bf85938ab9cbd36a7f321104014;p=thirdparty%2Fccache.git

New command-line option -k/--get-config prints the value of a config key

We print exactly the value of the configuration setting, rather
than a full item pair "(origin) key = value" as --print-config does.

This is useful for scripting. For example, $(ccache -k cache_dir)
gives the cache directory path.
---

diff --git a/src/ccache.c b/src/ccache.c
index 0665582fd..1a9ba146f 100644
--- a/src/ccache.c
+++ b/src/ccache.c
@@ -66,6 +66,7 @@ static const char USAGE_TEXT[] =
 	"    -C, --clear           clear the cache completely (except configuration)\n"
 	"    -F, --max-files=N     set maximum number of files in cache to N (use 0 for\n"
 	"                          no limit)\n"
+        "    -k, --get-config=K    get the value of the configuration key K\n"
 	"    -M, --max-size=SIZE   set maximum size of cache to SIZE (use 0 for no\n"
 	"                          limit); available suffixes: k, M, G, T (decimal) and\n"
 	"                          Ki, Mi, Gi, Ti (binary); default suffix: G\n"
@@ -3544,6 +3545,7 @@ ccache_main_options(int argc, char *argv[])
 		{"cleanup",       no_argument,       0, 'c'},
 		{"clear",         no_argument,       0, 'C'},
 		{"dump-manifest", required_argument, 0, DUMP_MANIFEST},
+		{"get-config",    required_argument, 0, 'k'},
 		{"hash-file",     required_argument, 0, HASH_FILE},
 		{"help",          no_argument,       0, 'h'},
 		{"max-files",     required_argument, 0, 'F'},
@@ -3557,7 +3559,8 @@ ccache_main_options(int argc, char *argv[])
 	};
 
 	int c;
-	while ((c = getopt_long(argc, argv, "cChF:M:o:psVz", options, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "cCk:hF:M:o:psVz", options, NULL))
+               != -1) {
 		switch (c) {
 		case DUMP_MANIFEST:
 			manifest_dump(optarg, stdout);
@@ -3595,6 +3598,16 @@ ccache_main_options(int argc, char *argv[])
 			fputs(USAGE_TEXT, stdout);
 			x_exit(0);
 
+		case 'k': // --get-config
+		{
+			initialize();
+			char *errmsg;
+			if (!conf_print_value(conf, optarg, stdout, &errmsg)) {
+				fatal("%s", errmsg);
+			}
+		}
+		break;
+
 		case 'F': // --max-files
 		{
 			initialize();
diff --git a/src/conf.c b/src/conf.c
index 2bf96bcb4..404d2d7f7 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -629,6 +629,22 @@ conf_set_value_in_file(const char *path, const char *key, const char *value,
 	return true;
 }
 
+bool
+conf_print_value(struct conf *conf, const char *key,
+                 FILE *file, char **errmsg)
+{
+	const struct conf_item *item = find_conf(key);
+	if (!item) {
+		*errmsg = format("unknown configuration option \"%s\"", key);
+		return false;
+	}
+	void *value = (char *)conf + item->offset;
+	char *str = (char *)item->formatter(value);
+	fprintf(file, "%s\n", str);
+	free(str);
+	return true;
+}
+
 static bool
 print_item(struct conf *conf, const char *key,
            void (*printer)(const char *descr, const char *origin,
diff --git a/src/conf.h b/src/conf.h
index b0ace1c29..9c9e28f42 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -45,6 +45,8 @@ struct conf *conf_create(void);
 void conf_free(struct conf *conf);
 bool conf_read(struct conf *conf, const char *path, char **errmsg);
 bool conf_update_from_environment(struct conf *conf, char **errmsg);
+bool conf_print_value(struct conf *conf, const char *key,
+                      FILE *file, char **errmsg);
 bool conf_set_value_in_file(const char *path, const char *key,
                             const char *value, char **errmsg);
 bool conf_print_items(struct conf *conf,
diff --git a/unittest/test_conf.c b/unittest/test_conf.c
index 2028ddc8c..f3d63da98 100644
--- a/unittest/test_conf.c
+++ b/unittest/test_conf.c
@@ -383,6 +383,50 @@ TEST(conf_set_existing_value)
 	CHECK_STR_EQ_FREE2("path = vanilla\nstats = chocolate\n", data);
 }
 
+TEST(conf_print_existing_value)
+{
+	struct conf *conf = conf_create();
+	conf->max_files = 42;
+	char *errmsg;
+	{
+		FILE *log = fopen("log", "w");
+		CHECK(log);
+		CHECK(conf_print_value(conf, "max_files", log, &errmsg));
+		fclose(log);
+	}
+	{
+		FILE *log = fopen("log", "r");
+		CHECK(log);
+		char buf[100];
+		CHECK(fgets(buf, 100, log));
+		CHECK_STR_EQ("42\n", buf);
+		fclose(log);
+	}
+	conf_free(conf);
+}
+
+TEST(conf_print_unknown_value)
+{
+	struct conf *conf = conf_create();
+	char *errmsg;
+	{
+		FILE *log = fopen("log", "w");
+		CHECK(log);
+		CHECK(!conf_print_value(conf, "foo", log, &errmsg));
+		CHECK_STR_EQ_FREE2("unknown configuration option \"foo\"",
+				   errmsg);
+		fclose(log);
+	}
+	{
+		FILE *log = fopen("log", "r");
+		CHECK(log);
+		char buf[100];
+		CHECK(!fgets(buf, 100, log));
+		fclose(log);
+	}
+	conf_free(conf);
+}
+
 TEST(conf_print_items)
 {
 	size_t i;