lockfile.h: extract new header file for the functions in lockfile.c

Move the interface declaration for the functions in lockfile.c from
cache.h to a new file, lockfile.h. Add #includes where necessary (and
remove some redundant includes of cache.h by files that already
include builtin.h).

Move the documentation of the lock_file state diagram from lockfile.c
to the new header file.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

35 files changed, 118 insertions, 83 deletions

diff --git a/builtin/add.c b/builtin/add.c
index 352b85e8db..ae6d3e262b 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -5,6 +5,7 @@
  */
 #include "cache.h"
 #include "builtin.h"
+#include "lockfile.h"
 #include "dir.h"
 #include "pathspec.h"
 #include "exec_cmd.h"
diff --git a/builtin/apply.c b/builtin/apply.c
index 8714a88720..69efb0e4df 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -7,6 +7,7 @@
  *
  */
 #include "cache.h"
+#include "lockfile.h"
 #include "cache-tree.h"
 #include "quote.h"
 #include "blob.h"
diff --git a/builtin/checkout-index.c b/builtin/checkout-index.c
index 05edd9e1df..383dccf93e 100644
--- a/builtin/checkout-index.c
+++ b/builtin/checkout-index.c
@@ -5,7 +5,7 @@
  *
  */
 #include "builtin.h"
-#include "cache.h"
+#include "lockfile.h"
 #include "quote.h"
 #include "cache-tree.h"
 #include "parse-options.h"
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8afdf2b5c4..570bb09c4f 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1,5 +1,5 @@
-#include "cache.h"
 #include "builtin.h"
+#include "lockfile.h"
 #include "parse-options.h"
 #include "refs.h"
 #include "commit.h"
diff --git a/builtin/clone.c b/builtin/clone.c
index 3927edfb6e..d3bf9532d6 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -9,6 +9,7 @@
  */
 
 #include "builtin.h"
+#include "lockfile.h"
 #include "parse-options.h"
 #include "fetch-pack.h"
 #include "refs.h"
diff --git a/builtin/commit.c b/builtin/commit.c
index f55e80986b..c2300185ec 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -6,6 +6,7 @@
  */
 
 #include "cache.h"
+#include "lockfile.h"
 #include "cache-tree.h"
 #include "color.h"
 #include "dir.h"
diff --git a/builtin/describe.c b/builtin/describe.c
index ee6a3b998f..9103193b4f 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "commit.h"
 #include "tag.h"
 #include "refs.h"
diff --git a/builtin/diff.c b/builtin/diff.c
index 0f247d2400..4326fa56bf 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2006 Junio C Hamano
  */
 #include "cache.h"
+#include "lockfile.h"
 #include "color.h"
 #include "commit.h"
 #include "blob.h"
diff --git a/builtin/gc.c b/builtin/gc.c
index ced1456e1e..005adbebea 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -11,7 +11,7 @@
  */
 
 #include "builtin.h"
-#include "cache.h"
+#include "lockfile.h"
 #include "parse-options.h"
 #include "run-command.h"
 #include "sigchain.h"
diff --git a/builtin/merge.c b/builtin/merge.c
index be07f27487..4513fadc5f 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -9,6 +9,7 @@
 #include "cache.h"
 #include "parse-options.h"
 #include "builtin.h"
+#include "lockfile.h"
 #include "run-command.h"
 #include "diff.h"
 #include "refs.h"
diff --git a/builtin/mv.c b/builtin/mv.c
index 8883baa903..563d05ba1a 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -3,8 +3,8 @@
  *
  * Copyright (C) 2006 Johannes Schindelin
  */
-#include "cache.h"
 #include "builtin.h"
+#include "lockfile.h"
 #include "dir.h"
 #include "cache-tree.h"
 #include "string-list.h"
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index e7e1c33a7f..43b47f72f1 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -5,6 +5,7 @@
  */
 
 #include "cache.h"
+#include "lockfile.h"
 #include "object.h"
 #include "tree.h"
 #include "tree-walk.h"
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index daf0600ca3..10fa25d7b5 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -1,4 +1,5 @@
 #include "builtin.h"
+#include "lockfile.h"
 #include "pack.h"
 #include "refs.h"
 #include "pkt-line.h"
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 7c78b15c14..b6388f75b0 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -1,5 +1,5 @@
-#include "cache.h"
 #include "builtin.h"
+#include "lockfile.h"
 #include "commit.h"
 #include "refs.h"
 #include "dir.h"
diff --git a/builtin/reset.c b/builtin/reset.c
index 855d478e3b..4c08ddc1ca 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -8,6 +8,7 @@
  * Copyright (c) 2005, 2006 Linus Torvalds and Junio C Hamano
  */
 #include "builtin.h"
+#include "lockfile.h"
 #include "tag.h"
 #include "object.h"
 #include "commit.h"
diff --git a/builtin/rm.c b/builtin/rm.c
index 2b61d3bd41..d8a9c86dd1 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -3,8 +3,8 @@
  *
  * Copyright (C) Linus Torvalds 2006
  */
-#include "cache.h"
 #include "builtin.h"
+#include "lockfile.h"
 #include "dir.h"
 #include "cache-tree.h"
 #include "tree-walk.h"
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 6c9598891d..b0e3dc9105 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -4,6 +4,7 @@
  * Copyright (C) Linus Torvalds, 2005
  */
 #include "cache.h"
+#include "lockfile.h"
 #include "quote.h"
 #include "cache-tree.h"
 #include "tree-walk.h"
diff --git a/bundle.c b/bundle.c
index b2b89fe862..891a3cacda 100644
--- a/bundle.c
+++ b/bundle.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "bundle.h"
 #include "object.h"
 #include "commit.h"
diff --git a/cache-tree.c b/cache-tree.c
index 75a54fdc72..215202c42d 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "tree.h"
 #include "tree-walk.h"
 #include "cache-tree.h"
diff --git a/cache.h b/cache.h
index d19e57ff64..b71ceb2d8d 100644
--- a/cache.h
+++ b/cache.h
@@ -570,36 +570,11 @@ extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
 #define REFRESH_IN_PORCELAIN	0x0020	/* user friendly output, not "needs update" */
 extern int refresh_index(struct index_state *, unsigned int flags, const struct pathspec *pathspec, char *seen, const char *header_msg);
 
-/* String appended to a filename to derive the lockfile name: */
-#define LOCK_SUFFIX ".lock"
-#define LOCK_SUFFIX_LEN 5
-
-struct lock_file {
-	struct lock_file *volatile next;
-	volatile sig_atomic_t active;
-	volatile int fd;
-	volatile pid_t owner;
-	char on_list;
-	struct strbuf filename;
-};
-#define LOCK_DIE_ON_ERROR 1
-#define LOCK_NO_DEREF 2
-extern int unable_to_lock_error(const char *path, int err);
-extern void unable_to_lock_message(const char *path, int err,
-				   struct strbuf *buf);
-extern NORETURN void unable_to_lock_die(const char *path, int err);
-extern int hold_lock_file_for_update(struct lock_file *, const char *path, int);
-extern int hold_lock_file_for_append(struct lock_file *, const char *path, int);
-extern char *get_locked_file_path(struct lock_file *);
-extern int commit_lock_file_to(struct lock_file *, const char *path);
-extern int commit_lock_file(struct lock_file *);
-extern int reopen_lock_file(struct lock_file *);
 extern void update_index_if_able(struct index_state *, struct lock_file *);
 
 extern int hold_locked_index(struct lock_file *, int);
 extern void set_alternate_index_output(const char *);
-extern int close_lock_file(struct lock_file *);
-extern void rollback_lock_file(struct lock_file *);
+
 extern int delete_ref(const char *, const unsigned char *sha1, int delopt);
 
 /* Environment bits from configuration mechanism */
diff --git a/config.c b/config.c
index 21107797d3..c31d4d2486 100644
--- a/config.c
+++ b/config.c
@@ -6,6 +6,7 @@
  *
  */
 #include "cache.h"
+#include "lockfile.h"
 #include "exec_cmd.h"
 #include "strbuf.h"
 #include "quote.h"
diff --git a/credential-store.c b/credential-store.c
index f9146e576f..d435514cbe 100644
--- a/credential-store.c
+++ b/credential-store.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "credential.h"
 #include "string-list.h"
 #include "parse-options.h"
diff --git a/fast-import.c b/fast-import.c
index 783c6840b5..deadc33f94 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -153,6 +153,7 @@ Format of STDIN stream:
 
 #include "builtin.h"
 #include "cache.h"
+#include "lockfile.h"
 #include "object.h"
 #include "blob.h"
 #include "tree.h"
diff --git a/fetch-pack.c b/fetch-pack.c
index 7487aa7306..655ee64256 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "refs.h"
 #include "pkt-line.h"
 #include "commit.h"
diff --git a/lockfile.c b/lockfile.c
index 63f4e94bce..d27e61cafc 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -2,59 +2,9 @@
  * Copyright (c) 2005, Junio C Hamano
  */
 #include "cache.h"
+#include "lockfile.h"
 #include "sigchain.h"
 
-/*
- * File write-locks as used by Git.
- *
- * For an overview of how to use the lockfile API, please see
- *
- *     Documentation/technical/api-lockfile.txt
- *
- * This module keeps track of all locked files in lock_file_list for
- * use at cleanup. This list and the lock_file objects that comprise
- * it must be kept in self-consistent states at all time, because the
- * program can be interrupted any time by a signal, in which case the
- * signal handler will walk through the list attempting to clean up
- * any open lock files.
- *
- * A lockfile is owned by the process that created it. The lock_file
- * object has an "owner" field that records its owner. This field is
- * used to prevent a forked process from closing a lockfile created by
- * its parent.
- *
- * The possible states of a lock_file object are as follows:
- *
- * - Uninitialized.  In this state the object's on_list field must be
- *   zero but the rest of its contents need not be initialized.  As
- *   soon as the object is used in any way, it is irrevocably
- *   registered in the lock_file_list, and on_list is set.
- *
- * - Locked, lockfile open (after hold_lock_file_for_update(),
- *   hold_lock_file_for_append(), or reopen_lock_file()). In this
- *   state:
- *   - the lockfile exists
- *   - active is set
- *   - filename holds the filename of the lockfile
- *   - fd holds a file descriptor open for writing to the lockfile
- *   - owner holds the PID of the process that locked the file
- *
- * - Locked, lockfile closed (after successful close_lock_file()).
- *   Same as the previous state, except that the lockfile is closed
- *   and fd is -1.
- *
- * - Unlocked (after commit_lock_file(), commit_lock_file_to(),
- *   rollback_lock_file(), a failed attempt to lock, or a failed
- *   close_lock_file()).  In this state:
- *   - active is unset
- *   - filename is empty (usually, though there are transitory
- *     states in which this condition doesn't hold). Client code should
- *     *not* rely on the filename being empty in this state.
- *   - fd is -1
- *   - the object is left registered in the lock_file_list, and
- *     on_list is set.
- */
-
 static struct lock_file *volatile lock_file_list;
 
 static void remove_lock_files(void)
diff --git a/lockfile.h b/lockfile.h
new file mode 100644
index 0000000000..9059e8958f
--- /dev/null
+++ b/lockfile.h
@@ -0,0 +1,84 @@
+#ifndef LOCKFILE_H
+#define LOCKFILE_H
+
+/*
+ * File write-locks as used by Git.
+ *
+ * For an overview of how to use the lockfile API, please see
+ *
+ *     Documentation/technical/api-lockfile.txt
+ *
+ * This module keeps track of all locked files in lock_file_list for
+ * use at cleanup. This list and the lock_file objects that comprise
+ * it must be kept in self-consistent states at all time, because the
+ * program can be interrupted any time by a signal, in which case the
+ * signal handler will walk through the list attempting to clean up
+ * any open lock files.
+ *
+ * A lockfile is owned by the process that created it. The lock_file
+ * object has an "owner" field that records its owner. This field is
+ * used to prevent a forked process from closing a lockfile created by
+ * its parent.
+ *
+ * The possible states of a lock_file object are as follows:
+ *
+ * - Uninitialized.  In this state the object's on_list field must be
+ *   zero but the rest of its contents need not be initialized.  As
+ *   soon as the object is used in any way, it is irrevocably
+ *   registered in the lock_file_list, and on_list is set.
+ *
+ * - Locked, lockfile open (after hold_lock_file_for_update(),
+ *   hold_lock_file_for_append(), or reopen_lock_file()). In this
+ *   state:
+ *   - the lockfile exists
+ *   - active is set
+ *   - filename holds the filename of the lockfile
+ *   - fd holds a file descriptor open for writing to the lockfile
+ *   - owner holds the PID of the process that locked the file
+ *
+ * - Locked, lockfile closed (after successful close_lock_file()).
+ *   Same as the previous state, except that the lockfile is closed
+ *   and fd is -1.
+ *
+ * - Unlocked (after commit_lock_file(), commit_lock_file_to(),
+ *   rollback_lock_file(), a failed attempt to lock, or a failed
+ *   close_lock_file()).  In this state:
+ *   - active is unset
+ *   - filename is empty (usually, though there are transitory
+ *     states in which this condition doesn't hold). Client code should
+ *     *not* rely on the filename being empty in this state.
+ *   - fd is -1
+ *   - the object is left registered in the lock_file_list, and
+ *     on_list is set.
+ */
+
+struct lock_file {
+	struct lock_file *volatile next;
+	volatile sig_atomic_t active;
+	volatile int fd;
+	volatile pid_t owner;
+	char on_list;
+	struct strbuf filename;
+};
+
+/* String appended to a filename to derive the lockfile name: */
+#define LOCK_SUFFIX ".lock"
+#define LOCK_SUFFIX_LEN 5
+
+#define LOCK_DIE_ON_ERROR 1
+#define LOCK_NO_DEREF 2
+
+extern int unable_to_lock_error(const char *path, int err);
+extern void unable_to_lock_message(const char *path, int err,
+				   struct strbuf *buf);
+extern NORETURN void unable_to_lock_die(const char *path, int err);
+extern int hold_lock_file_for_update(struct lock_file *, const char *path, int);
+extern int hold_lock_file_for_append(struct lock_file *, const char *path, int);
+extern char *get_locked_file_path(struct lock_file *);
+extern int commit_lock_file_to(struct lock_file *, const char *path);
+extern int commit_lock_file(struct lock_file *);
+extern int reopen_lock_file(struct lock_file *);
+extern int close_lock_file(struct lock_file *);
+extern void rollback_lock_file(struct lock_file *);
+
+#endif /* LOCKFILE_H */
diff --git a/merge-recursive.c b/merge-recursive.c
index 8ad4be897d..4b0884b7bb 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -5,6 +5,7 @@
  */
 #include "advice.h"
 #include "cache.h"
+#include "lockfile.h"
 #include "cache-tree.h"
 #include "commit.h"
 #include "blob.h"
diff --git a/merge.c b/merge.c
index 74ced7f70b..fcff632bd6 100644
--- a/merge.c
+++ b/merge.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "commit.h"
 #include "run-command.h"
 #include "resolve-undo.h"
diff --git a/read-cache.c b/read-cache.c
index 9f137e7f27..8f3e9eb314 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -5,6 +5,7 @@
  */
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
+#include "lockfile.h"
 #include "cache-tree.h"
 #include "refs.h"
 #include "dir.h"
diff --git a/refs.c b/refs.c
index e40c47edce..1d73f1daf5 100644
--- a/refs.c
+++ b/refs.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "refs.h"
 #include "object.h"
 #include "tag.h"
diff --git a/rerere.c b/rerere.c
index 20b18add42..1b0555f1a5 100644
--- a/rerere.c
+++ b/rerere.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "string-list.h"
 #include "rerere.h"
 #include "xdiff-interface.h"
diff --git a/sequencer.c b/sequencer.c
index 5e8a207474..1b9a35e587 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "sequencer.h"
 #include "dir.h"
 #include "object.h"
diff --git a/sha1_file.c b/sha1_file.c
index c08c0cbea8..46ff273e27 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -8,6 +8,7 @@
  */
 #include "cache.h"
 #include "string-list.h"
+#include "lockfile.h"
 #include "delta.h"
 #include "pack.h"
 #include "blob.h"
diff --git a/shallow.c b/shallow.c
index 4919baf772..bd7569e815 100644
--- a/shallow.c
+++ b/shallow.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "commit.h"
 #include "tag.h"
 #include "pkt-line.h"
diff --git a/test-scrap-cache-tree.c b/test-scrap-cache-tree.c
index 9ebcbca9d2..6efee31a48 100644
--- a/test-scrap-cache-tree.c
+++ b/test-scrap-cache-tree.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "lockfile.h"
 #include "tree.h"
 #include "cache-tree.h"