Make index file locking code reusable to others.

The framework to create lockfiles that are removed at exit is
first used to reliably write the index file, but it is
applicable to other things, so stop calling it "cache_file".

This also rewords a few remaining error message that called the
index file "cache file".

Signed-off-by: Junio C Hamano <junkio@cox.net>

11 files changed, 98 insertions, 95 deletions

diff --git a/Makefile b/Makefile
index f802043aa9..265a716704 100644
--- a/Makefile
+++ b/Makefile
@@ -210,7 +210,7 @@ DIFF_OBJS = \
 
 LIB_OBJS = \
 	blob.o commit.o connect.o csum-file.o cache-tree.o base85.o \
-	date.o diff-delta.o entry.o exec_cmd.o ident.o index.o \
+	date.o diff-delta.o entry.o exec_cmd.o ident.o lockfile.o \
 	object.o pack-check.o patch-delta.o path.o pkt-line.o \
 	quote.o read-cache.o refs.o run-command.o dir.o \
 	server-info.o setup.o sha1_file.o sha1_name.o strbuf.o \
diff --git a/builtin-add.c b/builtin-add.c
index 02fe38b0c4..bfbbb1bf52 100644
--- a/builtin-add.c
+++ b/builtin-add.c
@@ -122,7 +122,7 @@ static int add_file_to_index(const char *path, int verbose)
 	return 0;
 }
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 int cmd_add(int argc, const char **argv, char **envp)
 {
@@ -134,9 +134,9 @@ int cmd_add(int argc, const char **argv, char **envp)
 
 	git_config(git_default_config);
 
-	newfd = hold_index_file_for_update(&cache_file, get_index_file());
+	newfd = hold_lock_file_for_update(&lock_file, get_index_file());
 	if (newfd < 0)
-		die("unable to create new cachefile");
+		die("unable to create new index file");
 
 	if (read_cache() < 0)
 		die("index file corrupt");
@@ -181,7 +181,7 @@ int cmd_add(int argc, const char **argv, char **envp)
 
 	if (active_cache_changed) {
 		if (write_cache(newfd, active_cache, active_nr) ||
-		    commit_index_file(&cache_file))
+		    commit_lock_file(&lock_file))
 			die("Unable to write new index file");
 	}
 
diff --git a/builtin-apply.c b/builtin-apply.c
index 6a4fb9663d..e113c74dd8 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -2072,7 +2072,7 @@ static void write_out_results(struct patch *list, int skipped_patch)
 	}
 }
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 static struct excludes {
 	struct excludes *next;
@@ -2133,8 +2133,12 @@ static int apply_patch(int fd, const char *filename)
 		apply = 0;
 
 	write_index = check_index && apply;
-	if (write_index && newfd < 0)
-		newfd = hold_index_file_for_update(&cache_file, get_index_file());
+	if (write_index && newfd < 0) {
+		newfd = hold_lock_file_for_update(&lock_file,
+						  get_index_file());
+		if (newfd < 0)
+			die("unable to create new index file");
+	}
 	if (check_index) {
 		if (read_cache() < 0)
 			die("unable to read index file");
@@ -2312,8 +2316,8 @@ int cmd_apply(int argc, const char **argv, char **envp)
 
 	if (write_index) {
 		if (write_cache(newfd, active_cache, active_nr) ||
-		    commit_index_file(&cache_file))
-			die("Unable to write new cachefile");
+		    commit_lock_file(&lock_file))
+			die("Unable to write new index file");
 	}
 
 	return 0;
diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index 8d1a22d373..bb50fbd274 100644
--- a/builtin-read-tree.c
+++ b/builtin-read-tree.c
@@ -853,7 +853,7 @@ static void prime_cache_tree(void)
 
 static const char read_tree_usage[] = "git-read-tree (<sha> | -m [--aggressive] [-u | -i] <sha1> [<sha2> [<sha3>]])";
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 int cmd_read_tree(int argc, const char **argv, char **envp)
 {
@@ -864,9 +864,9 @@ int cmd_read_tree(int argc, const char **argv, char **envp)
 	setup_git_directory();
 	git_config(git_default_config);
 
-	newfd = hold_index_file_for_update(&cache_file, get_index_file());
+	newfd = hold_lock_file_for_update(&lock_file, get_index_file());
 	if (newfd < 0)
-		die("unable to create new cachefile");
+		die("unable to create new index file");
 
 	git_config(git_default_config);
 
@@ -981,7 +981,7 @@ int cmd_read_tree(int argc, const char **argv, char **envp)
 	}
 
 	if (write_cache(newfd, active_cache, active_nr) ||
-	    commit_index_file(&cache_file))
+	    commit_lock_file(&lock_file))
 		die("unable to write new index file");
 	return 0;
 }
diff --git a/builtin-rm.c b/builtin-rm.c
index e7793a20f5..ef2f8b5d09 100644
--- a/builtin-rm.c
+++ b/builtin-rm.c
@@ -41,7 +41,7 @@ static int remove_file(const char *name)
 	return ret;
 }
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 int cmd_rm(int argc, const char **argv, char **envp)
 {
@@ -53,7 +53,7 @@ int cmd_rm(int argc, const char **argv, char **envp)
 
 	git_config(git_default_config);
 
-	newfd = hold_index_file_for_update(&cache_file, get_index_file());
+	newfd = hold_lock_file_for_update(&lock_file, get_index_file());
 	if (newfd < 0)
 		die("unable to create new index file");
 
@@ -144,7 +144,7 @@ int cmd_rm(int argc, const char **argv, char **envp)
 
 	if (active_cache_changed) {
 		if (write_cache(newfd, active_cache, active_nr) ||
-		    commit_index_file(&cache_file))
+		    commit_lock_file(&lock_file))
 			die("Unable to write new index file");
 	}
 
diff --git a/cache.h b/cache.h
index d530af97cc..d5d7fe4f8c 100644
--- a/cache.h
+++ b/cache.h
@@ -167,13 +167,13 @@ extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
 #define REFRESH_IGNORE_MISSING	0x0008	/* ignore non-existent */
 extern int refresh_cache(unsigned int flags);
 
-struct cache_file {
-	struct cache_file *next;
-	char lockfile[PATH_MAX];
+struct lock_file {
+	struct lock_file *next;
+	char filename[PATH_MAX];
 };
-extern int hold_index_file_for_update(struct cache_file *, const char *path);
-extern int commit_index_file(struct cache_file *);
-extern void rollback_index_file(struct cache_file *);
+extern int hold_lock_file_for_update(struct lock_file *, const char *path);
+extern int commit_lock_file(struct lock_file *);
+extern void rollback_lock_file(struct lock_file *);
 
 /* Environment bits from configuration mechanism */
 extern int trust_executable_bit;
diff --git a/checkout-index.c b/checkout-index.c
index 9876af6fd6..ea40bc29be 100644
--- a/checkout-index.c
+++ b/checkout-index.c
@@ -168,7 +168,7 @@ static int checkout_all(void)
 static const char checkout_cache_usage[] =
 "git-checkout-index [-u] [-q] [-a] [-f] [-n] [--stage=[123]|all] [--prefix=<string>] [--temp] [--] <file>...";
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 int main(int argc, char **argv)
 {
@@ -211,9 +211,8 @@ int main(int argc, char **argv)
 		if (!strcmp(arg, "-u") || !strcmp(arg, "--index")) {
 			state.refresh_cache = 1;
 			if (newfd < 0)
-				newfd = hold_index_file_for_update
-					(&cache_file,
-					 get_index_file());
+				newfd = hold_lock_file_for_update
+					(&lock_file, get_index_file());
 			if (newfd < 0)
 				die("cannot open index.lock file.");
 			continue;
@@ -262,7 +261,7 @@ int main(int argc, char **argv)
 		 */
 		if (state.refresh_cache) {
 			close(newfd); newfd = -1;
-			rollback_index_file(&cache_file);
+			rollback_lock_file(&lock_file);
 		}
 		state.refresh_cache = 0;
 	}
@@ -312,7 +311,7 @@ int main(int argc, char **argv)
 
 	if (0 <= newfd &&
 	    (write_cache(newfd, active_cache, active_nr) ||
-	     commit_index_file(&cache_file)))
-		die("Unable to write new cachefile");
+	     commit_lock_file(&lock_file)))
+		die("Unable to write new index file");
 	return 0;
 }
diff --git a/index.c b/index.c
deleted file mode 100644
index f92b960ae4..0000000000
--- a/index.c
+++ /dev/null
@@ -1,57 +0,0 @@
-/*
- * Copyright (c) 2005, Junio C Hamano
- */
-#include <signal.h>
-#include "cache.h"
-
-static struct cache_file *cache_file_list;
-
-static void remove_lock_file(void)
-{
-	while (cache_file_list) {
-		if (cache_file_list->lockfile[0])
-			unlink(cache_file_list->lockfile);
-		cache_file_list = cache_file_list->next;
-	}
-}
-
-static void remove_lock_file_on_signal(int signo)
-{
-	remove_lock_file();
-	signal(SIGINT, SIG_DFL);
-	raise(signo);
-}
-
-int hold_index_file_for_update(struct cache_file *cf, const char *path)
-{
-	int fd;
-	sprintf(cf->lockfile, "%s.lock", path);
-	fd = open(cf->lockfile, O_RDWR | O_CREAT | O_EXCL, 0666);
-	if (fd >=0 && !cf->next) {
-		cf->next = cache_file_list;
-		cache_file_list = cf;
-		signal(SIGINT, remove_lock_file_on_signal);
-		atexit(remove_lock_file);
-	}
-	return fd;
-}
-
-int commit_index_file(struct cache_file *cf)
-{
-	char indexfile[PATH_MAX];
-	int i;
-	strcpy(indexfile, cf->lockfile);
-	i = strlen(indexfile) - 5; /* .lock */
-	indexfile[i] = 0;
-	i = rename(cf->lockfile, indexfile);
-	cf->lockfile[0] = 0;
-	return i;
-}
-
-void rollback_index_file(struct cache_file *cf)
-{
-	if (cf->lockfile[0])
-		unlink(cf->lockfile);
-	cf->lockfile[0] = 0;
-}
-
diff --git a/lockfile.c b/lockfile.c
new file mode 100644
index 0000000000..9bc60837aa
--- /dev/null
+++ b/lockfile.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2005, Junio C Hamano
+ */
+#include <signal.h>
+#include "cache.h"
+
+static struct lock_file *lock_file_list;
+
+static void remove_lock_file(void)
+{
+	while (lock_file_list) {
+		if (lock_file_list->filename[0])
+			unlink(lock_file_list->filename);
+		lock_file_list = lock_file_list->next;
+	}
+}
+
+static void remove_lock_file_on_signal(int signo)
+{
+	remove_lock_file();
+	signal(SIGINT, SIG_DFL);
+	raise(signo);
+}
+
+int hold_lock_file_for_update(struct lock_file *lk, const char *path)
+{
+	int fd;
+	sprintf(lk->filename, "%s.lock", path);
+	fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
+	if (fd >=0 && !lk->next) {
+		lk->next = lock_file_list;
+		lock_file_list = lk;
+		signal(SIGINT, remove_lock_file_on_signal);
+		atexit(remove_lock_file);
+	}
+	return fd;
+}
+
+int commit_lock_file(struct lock_file *lk)
+{
+	char result_file[PATH_MAX];
+	int i;
+	strcpy(result_file, lk->filename);
+	i = strlen(result_file) - 5; /* .lock */
+	result_file[i] = 0;
+	i = rename(lk->filename, result_file);
+	lk->filename[0] = 0;
+	return i;
+}
+
+void rollback_lock_file(struct lock_file *lk)
+{
+	if (lk->filename[0])
+		unlink(lk->filename);
+	lk->filename[0] = 0;
+}
+
diff --git a/update-index.c b/update-index.c
index 956b6b34f9..fbccc4a67b 100644
--- a/update-index.c
+++ b/update-index.c
@@ -186,7 +186,7 @@ static void chmod_path(int flip, const char *path)
 	die("git-update-index: cannot chmod %cx '%s'", flip, path);
 }
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 static void update_one(const char *path, const char *prefix, int prefix_length)
 {
@@ -489,9 +489,9 @@ int main(int argc, const char **argv)
 
 	git_config(git_default_config);
 
-	newfd = hold_index_file_for_update(&cache_file, get_index_file());
+	newfd = hold_lock_file_for_update(&lock_file, get_index_file());
 	if (newfd < 0)
-		die("unable to create new cachefile");
+		die("unable to create new index file");
 
 	entries = read_cache();
 	if (entries < 0)
@@ -645,8 +645,8 @@ int main(int argc, const char **argv)
  finish:
 	if (active_cache_changed) {
 		if (write_cache(newfd, active_cache, active_nr) ||
-		    commit_index_file(&cache_file))
-			die("Unable to write new cachefile");
+		    commit_lock_file(&lock_file))
+			die("Unable to write new index file");
 	}
 
 	return has_errors ? 1 : 0;
diff --git a/write-tree.c b/write-tree.c
index 7a4f691d8a..d6a605893d 100644
--- a/write-tree.c
+++ b/write-tree.c
@@ -11,7 +11,7 @@ static int missing_ok = 0;
 
 static const char write_tree_usage[] = "git-write-tree [--missing-ok]";
 
-static struct cache_file cache_file;
+static struct lock_file lock_file;
 
 int main(int argc, char **argv)
 {
@@ -19,7 +19,7 @@ int main(int argc, char **argv)
 
 	setup_git_directory();
 
-	newfd = hold_index_file_for_update(&cache_file, get_index_file());
+	newfd = hold_lock_file_for_update(&lock_file, get_index_file());
 	entries = read_cache();
 	if (argc == 2) {
 		if (!strcmp(argv[1], "--missing-ok"))
@@ -45,7 +45,7 @@ int main(int argc, char **argv)
 			die("git-write-tree: error building trees");
 		if (0 <= newfd) {
 			if (!write_cache(newfd, active_cache, active_nr))
-				commit_index_file(&cache_file);
+				commit_lock_file(&lock_file);
 		}
 		/* Not being able to write is fine -- we are only interested
 		 * in updating the cache-tree part, and if the next caller