From: Junio C Hamano Date: Thu, 17 Jan 2008 02:43:10 +0000 (+0000) Subject: Autogenerated HTML docs for v1.5.4-rc3-24-gb53139 X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=5bd1d59aaa088d93ce9a070bdb715f335892a53c;p=git.git Autogenerated HTML docs for v1.5.4-rc3-24-gb53139 --- diff --git a/git-merge.html b/git-merge.html index 2f72cda7a..cda152801 100644 --- a/git-merge.html +++ b/git-merge.html @@ -510,14 +510,14 @@ report no changes.

Note
-This is a bit of lie. In certain special cases, your index are -allowed to be different from the tree of HEAD commit. The most +This is a bit of a lie. In certain special cases, your index is +allowed to be different from the tree of the HEAD commit. The most notable case is when your HEAD commit is already ahead of what is being merged, in which case your index can have arbitrary -difference from your HEAD commit. Otherwise, your index entries -are allowed have differences from your HEAD commit that match -the result of trivial merge (e.g. you received the same patch -from external source to produce the same result as what you are +differences from your HEAD commit. Also, your index entries +may have differences from your HEAD commit that match +the result of a trivial merge (e.g. you received the same patch +from an external source to produce the same result as what you are merging). For example, if a path did not exist in the common ancestor and your head commit but exists in the tree you are merging into your repository, and if you already happen to have @@ -649,7 +649,7 @@ Resolve the conflicts. git-diff would report only the diff --git a/git-merge.txt b/git-merge.txt index ed3a92404..0c9ad7f2b 100644 --- a/git-merge.txt +++ b/git-merge.txt @@ -74,14 +74,14 @@ it happens. In other words, `git-diff --cached HEAD` must report no changes. [NOTE] -This is a bit of lie. In certain special cases, your index are -allowed to be different from the tree of `HEAD` commit. The most +This is a bit of a lie. In certain special cases, your index is +allowed to be different from the tree of the `HEAD` commit. The most notable case is when your `HEAD` commit is already ahead of what is being merged, in which case your index can have arbitrary -difference from your `HEAD` commit. Otherwise, your index entries -are allowed have differences from your `HEAD` commit that match -the result of trivial merge (e.g. you received the same patch -from external source to produce the same result as what you are +differences from your `HEAD` commit. Also, your index entries +may have differences from your `HEAD` commit that match +the result of a trivial merge (e.g. you received the same patch +from an external source to produce the same result as what you are merging). For example, if a path did not exist in the common ancestor and your head commit but exists in the tree you are merging into your repository, and if you already happen to have diff --git a/technical/api-lockfile.html b/technical/api-lockfile.html index 4cf84abba..e41f6e089 100644 --- a/technical/api-lockfile.html +++ b/technical/api-lockfile.html @@ -263,36 +263,105 @@ div.exampleblock-content {
-

Talk about <lockfile.c>, things like:

+

The lockfile API serves two purposes:

  • -lockfile lifetime — atexit(3) looks at them, do not put them on the - stack; +Mutual exclusion. When we write out a new index file, first + we create a new file $GIT_DIR/index.lock, write the new + contents into it, and rename it to the final destination + $GIT_DIR/index. We try to create the $GIT_DIR/index.lock + file with O_EXCL so that we can notice and fail when somebody + else is already trying to update the index file.

  • -hold_lock_file_for_update() +Automatic cruft removal. After we create the "lock" file, we + may decide to die(), and we would want to make sure that we + remove the file that has not been committed to its final + destination. This is done by remembering the lockfiles we + created in a linked list and cleaning them up from an + atexit(3) handler. Outstanding lockfiles are also removed + when the program dies on a signal.

    • -
  • +
+
+
+

The functions

+
+
+
+hold_lock_file_for_update +
+

-commit_lock_file() + Take a pointer to struct lock_file, the filename of + the final destination (e.g. $GIT_DIR/index) and a flag + die_on_error. Attempt to create a lockfile for the + destination and return the file descriptor for writing + to the file. If die_on_error flag is true, it dies if + a lock is already taken for the file; otherwise it + returns a negative integer to the caller on failure.

- -
  • +
    • +
    +commit_lock_file +
    +

    -rollback_rock_file() + Take a pointer to the struct lock_file initialized + with an earlier call to hold_lock_file_for_update(), + close the file descriptor and rename the lockfile to its + final destination. Returns 0 upon success, a negative + value on failure to close(2) or rename(2).

    - - -

    (JC, Dscho, Shawn)

    -
    + +
    +rollback_lock_file +
    +
    +

    + Take a pointer to the struct lock_file initialized + with an earlier call to hold_lock_file_for_update(), + close the file descriptor and remove the lockfile. +

    +
    +
    +close_lock_file +
    +
    +

    + Take a pointer to the struct lock_file initialized + with an earlier call to hold_lock_file_for_update(), + and close the file descriptor. Returns 0 upon success, + a negative value on failure to close(2). +

    +
    + +

    Because the structure is used in an atexit(3) handler, its +storage has to stay throughout the life of the program. It +cannot be an auto variable allocated on the stack.

    +

    Call commit_lock_file() or rollback_lock_file() when you are +done writing to the file descriptor. If you do not call either +and simply exit(3) from the program, an atexit(3) handler +will close and remove the lockfile.

    +

    If you need to close the file descriptor you obtained from +hold_lock_file_for_update function yourself, do so by calling +close_lock_file(). You should never call close(2) yourself! +Otherwise the struct +lock_file structure still remembers that the file descriptor +needs to be closed, and a later call to commit_lock_file() or +rollback_lock_file() will result in duplicate calls to +close(2). Worse yet, if you close(2), open another file +descriptor for completely different purpose, and then call +commit_lock_file() or rollback_lock_file(), they may close +that unrelated file descriptor.

    diff --git a/technical/api-lockfile.txt b/technical/api-lockfile.txt index 73ac1025f..dd894043a 100644 --- a/technical/api-lockfile.txt +++ b/technical/api-lockfile.txt @@ -1,12 +1,74 @@ lockfile API ============ -Talk about , things like: +The lockfile API serves two purposes: -* lockfile lifetime -- atexit(3) looks at them, do not put them on the - stack; -* hold_lock_file_for_update() -* commit_lock_file() -* rollback_rock_file() +* Mutual exclusion. When we write out a new index file, first + we create a new file `$GIT_DIR/index.lock`, write the new + contents into it, and rename it to the final destination + `$GIT_DIR/index`. We try to create the `$GIT_DIR/index.lock` + file with O_EXCL so that we can notice and fail when somebody + else is already trying to update the index file. -(JC, Dscho, Shawn) +* Automatic cruft removal. After we create the "lock" file, we + may decide to `die()`, and we would want to make sure that we + remove the file that has not been committed to its final + destination. This is done by remembering the lockfiles we + created in a linked list and cleaning them up from an + `atexit(3)` handler. Outstanding lockfiles are also removed + when the program dies on a signal. + + +The functions +------------- + +hold_lock_file_for_update:: + + Take a pointer to `struct lock_file`, the filename of + the final destination (e.g. `$GIT_DIR/index`) and a flag + `die_on_error`. Attempt to create a lockfile for the + destination and return the file descriptor for writing + to the file. If `die_on_error` flag is true, it dies if + a lock is already taken for the file; otherwise it + returns a negative integer to the caller on failure. + +commit_lock_file:: + + Take a pointer to the `struct lock_file` initialized + with an earlier call to `hold_lock_file_for_update()`, + close the file descriptor and rename the lockfile to its + final destination. Returns 0 upon success, a negative + value on failure to close(2) or rename(2). + +rollback_lock_file:: + + Take a pointer to the `struct lock_file` initialized + with an earlier call to `hold_lock_file_for_update()`, + close the file descriptor and remove the lockfile. + +close_lock_file:: + Take a pointer to the `struct lock_file` initialized + with an earlier call to `hold_lock_file_for_update()`, + and close the file descriptor. Returns 0 upon success, + a negative value on failure to close(2). + +Because the structure is used in an `atexit(3)` handler, its +storage has to stay throughout the life of the program. It +cannot be an auto variable allocated on the stack. + +Call `commit_lock_file()` or `rollback_lock_file()` when you are +done writing to the file descriptor. If you do not call either +and simply `exit(3)` from the program, an `atexit(3)` handler +will close and remove the lockfile. + +If you need to close the file descriptor you obtained from +`hold_lock_file_for_update` function yourself, do so by calling +`close_lock_file()`. You should never call `close(2)` yourself! +Otherwise the `struct +lock_file` structure still remembers that the file descriptor +needs to be closed, and a later call to `commit_lock_file()` or +`rollback_lock_file()` will result in duplicate calls to +`close(2)`. Worse yet, if you `close(2)`, open another file +descriptor for completely different purpose, and then call +`commit_lock_file()` or `rollback_lock_file()`, they may close +that unrelated file descriptor.