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authorMichael Haggerty <mhagger@alum.mit.edu>2014-10-01 11:14:47 (GMT)
committerJunio C Hamano <gitster@pobox.com>2014-10-01 21:08:10 (GMT)
commit013870cd2cb1b0d6719a7a9123e126a62426520b (patch)
tree235000196a837c275d3e7d72d06cd3cf197bc9f3 /Documentation
parent697cc8efd944a32ca472337cd6640004c474b788 (diff)
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fdopen_lock_file(): access a lockfile using stdio
Add a new function, fdopen_lock_file(), which returns a FILE pointer open to the lockfile. If a stream is open on a lock_file object, it is closed using fclose() on commit, rollback, or close_lock_file(). This change will allow callers to use stdio to write to a lockfile without having to muck around in the internal representation of the lock_file object (callers will be rewritten in upcoming commits). Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/technical/api-lockfile.txt34
1 files changed, 23 insertions, 11 deletions
diff --git a/Documentation/technical/api-lockfile.txt b/Documentation/technical/api-lockfile.txt
index d4484d1..93b5f23 100644
--- a/Documentation/technical/api-lockfile.txt
+++ b/Documentation/technical/api-lockfile.txt
@@ -42,9 +42,13 @@ The caller:
of the final destination (e.g. `$GIT_DIR/index`) to
`hold_lock_file_for_update` or `hold_lock_file_for_append`.
-* Writes new content for the destination file by writing to the file
- descriptor returned by those functions (also available via
- `lock->fd`).
+* Writes new content for the destination file by either:
+
+ * writing to the file descriptor returned by the `hold_lock_file_*`
+ functions (also available via `lock->fd`).
+
+ * calling `fdopen_lock_file` to get a `FILE` pointer for the open
+ file and writing to the file using stdio.
When finished writing, the caller can:
@@ -70,10 +74,10 @@ any uncommitted changes.
If you need to close the file descriptor you obtained from a
`hold_lock_file_*` function yourself, do so by calling
-`close_lock_file`. You should never call `close(2)` yourself!
-Otherwise the `struct lock_file` structure would still think that the
-file descriptor needs to be closed, and a commit or rollback would
-result in duplicate calls to `close(2)`. Worse yet, if you `close(2)`
+`close_lock_file`. You should never call `close(2)` or `fclose(3)`
+yourself! Otherwise the `struct lock_file` structure would still think
+that the file descriptor needs to be closed, and a commit or rollback
+would result in duplicate calls to `close(2)`. Worse yet, if you close
and then later open another file descriptor for a completely different
purpose, then a commit or rollback might close that unrelated file
descriptor.
@@ -143,6 +147,13 @@ hold_lock_file_for_append::
the existing contents of the file (if any) to the lockfile and
position its write pointer at the end of the file.
+fdopen_lock_file::
+
+ Associate a stdio stream with the lockfile. Return NULL
+ (*without* rolling back the lockfile) on error. The stream is
+ closed automatically when `close_lock_file` is called or when
+ the file is committed or rolled back.
+
get_locked_file_path::
Return the path of the file that is locked by the specified
@@ -179,10 +190,11 @@ close_lock_file::
Take a pointer to the `struct lock_file` initialized with an
earlier call to `hold_lock_file_for_update` or
- `hold_lock_file_for_append`, and close the file descriptor.
- Return 0 upon success. On failure to `close(2)`, return a
- negative value and roll back the lock file. Usually
- `commit_lock_file`, `commit_lock_file_to`, or
+ `hold_lock_file_for_append`. Close the file descriptor (and
+ the file pointer if it has been opened using
+ `fdopen_lock_file`). Return 0 upon success. On failure to
+ `close(2)`, return a negative value and roll back the lock
+ file. Usually `commit_lock_file`, `commit_lock_file_to`, or
`rollback_lock_file` should eventually be called if
`close_lock_file` succeeds.