src/filebuf.c


Log

Author Commit Date CI Message
Sebastian Henke 3335a034 2019-10-10T15:28:46 refs: fix locks getting forcibly removed The flag GIT_FILEBUF_FORCE currently does two things: 1. It will cause the filebuf to create non-existing leading directories for the file that is about to be written. 2. It will forcibly remove any pre-existing locks. While most call sites actually do want (1), they do not want to remove pre-existing locks, as that renders the locking mechanisms effectively useless. Introduce a new flag `GIT_FILEBUF_CREATE_LEADING_DIRS` to separate both behaviours cleanly from each other and convert callers to use it instead of `GIT_FILEBUF_FORCE` to have them honor locked files correctly. As this conversion removes all current users of `GIT_FILEBUF_FORCE`, this commit removes the flag altogether.
Patrick Steinhardt e54343a4 2019-06-29T09:17:32 fileops: rename to "futils.h" to match function signatures Our file utils functions all have a "futils" prefix, e.g. `git_futils_touch`. One would thus naturally guess that their definitions and implementation would live in files "futils.h" and "futils.c", respectively, but in fact they live in "fileops.h". Rename the files to match expectations.
Edward Thomson f673e232 2018-12-27T13:47:34 git_error: use new names in internal APIs and usage Move to the `git_error` name in the internal API for error-related functions.
Patrick Steinhardt ecf4f33a 2018-02-08T11:14:48 Convert usage of `git_buf_free` to new `git_buf_dispose`
Patrick Steinhardt 0c7f49dd 2017-06-30T13:39:01 Make sure to always include "common.h" first Next to including several files, our "common.h" header also declares various macros which are then used throughout the project. As such, we have to make sure to always include this file first in all implementation files. Otherwise, we might encounter problems or even silent behavioural differences due to macros or defines not being defined as they should be. So in fact, our header and implementation files should make sure to always include "common.h" first. This commit does so by establishing a common include pattern. Header files inside of "src" will now always include "common.h" as its first other file, separated by a newline from all the other includes to make it stand out as special. There are two cases for the implementation files. If they do have a matching header file, they will always include this one first, leading to "common.h" being transitively included as first file. If they do not have a matching header file, they instead include "common.h" as first file themselves. This fixes the outlined problems and will become our standard practice for header and source files inside of the "src/" from now on.
Edward Thomson 6fd6c678 2017-03-22T20:29:22 Merge pull request #4030 from libgit2/ethomson/fsync fsync all the things
Sven Strickroth2 86a8cd9f 2017-03-20T11:21:00 filebuf: fix resolving absolute symlinks The symlink destination is always concatenated to the original path. Fix this by using `git_buf_sets` instead of `git_buf_puts`.
Edward Thomson 1229e1c4 2017-02-17T16:36:53 fsync parent directories when fsyncing When fsync'ing files, fsync the parent directory in the case where we rename a file into place, or create a new file, to ensure that the directory entry is flushed correctly.
Edward Thomson fc77891f 2016-12-13T10:07:42 git_filebuf: optionally fsync when committing
Edward Thomson 909d5494 2016-12-29T12:25:15 giterr_set: consistent error messages Error messages should be sentence fragments, and therefore: 1. Should not begin with a capital letter, 2. Should not conclude with punctuation, and 3. Should not end a sentence and begin a new one
Edward Thomson e3c42fee 2016-05-26T12:39:09 filebuf: fix uninitialized warning
Carlos Martín Nieto 3fa764ed 2015-11-04T09:20:14 filebuf: allow using a custom buffer size Allow setting the buffer size on open in order to use this data structure more generally as a spill buffer, with larger buffer sizes for specific use-cases.
Patrick Steinhardt 6ff8a7c4 2016-03-10T17:05:30 filebuf: handle write error in `lock_file` When writing to a file with locking not check if writing the locked file actually succeeds. Fix the issue by returning error code and message when writing fails.
Edward Thomson ec50b23a 2015-11-03T17:02:07 filebuf: detect directories in our way When creating a filebuf, detect a directory that exists in our target file location. This prevents a failure later, when we try to move the lock file to the destination.
Carlos Martín Nieto d83b2e9f 2015-09-05T03:54:06 filebuf: follow symlinks when creating a lock file We create a lockfile to update files under GIT_DIR. Sometimes these files are actually located elsewhere and a symlink takes their place. In that case we should lock and update the file at its final location rather than overwrite the symlink.
Carlos Martín Nieto 19d9beb7 2015-07-24T19:22:41 filebuf: remove lockfile upon rename errors When we have an error renaming the lockfile, we need to make sure that we remove it upon cleanup. For this, we need to keep track of whether we opened the file and whether the rename succeeded. If we did create the lockfile but the rename did not succeed, we remove the lockfile. This won't protect against all errors, but the most common ones (target file is open) does get handled.
J Wyman 7dd22538 2015-05-11T10:19:25 centralizing all IO buffer size values
Edward Thomson 8aab36a3 2015-02-12T22:14:53 filebuf: use an int for return check
Edward Thomson f1453c59 2015-02-12T12:19:37 Make our overflow check look more like gcc/clang's Make our overflow checking look more like gcc and clang's, so that we can substitute it out with the compiler instrinsics on platforms that support it. This means dropping the ability to pass `NULL` as an out parameter. As a result, the macros also get updated to reflect this as well.
Edward Thomson ec3b4d35 2015-02-11T11:20:05 Use `size_t` to hold size of arrays Use `size_t` to hold the size of arrays to ease overflow checking, lest we check for overflow of a `size_t` then promptly truncate by packing the length into a smaller type.
Edward Thomson 392702ee 2015-02-09T23:41:13 allocations: test for overflow of requested size Introduce some helper macros to test integer overflow from arithmetic and set error message appropriately.
Carlos Martín Nieto e58281aa 2014-04-04T14:40:38 filebuf: make unlocking atomic When renaming a lock file to its final location, we need to make sure that it is replaced atomically. We currently have a workaround for Windows by removing the target file. This means that the target file, which may be a ref or a packfile, may cease to exist for a short wile, which shold be avoided. Implement the workaround only in Windows, by making sure that the file we want to replace is writable.
Edward Thomson 4f46a98b 2014-02-24T23:32:25 Remove now-duplicated stdarg.h include
Edward Thomson 1d3a8aeb 2013-11-04T18:28:57 move mode_t to filebuf_open instead of _commit
Edward Thomson f966acd1 2013-11-04T15:46:32 Take umask into account in filebuf_commit
Carlos Martín Nieto 3d276874 2013-08-19T10:30:44 index: report when it's locked Report the index being locked with its own error code in order to be able to differentiate, as a locked index is typically the result of a crashed process or concurrent access, both of which often require user intervention to fix.
Edward Thomson 359fc2d2 2013-01-08T17:07:25 update copyrights
Edward Thomson 2a612fe3 2012-11-13T14:57:35 filebuf now has a git_hash_ctx instead of a ctx*
Edward Thomson d6fb0924 2012-11-05T12:37:15 Win32 CryptoAPI and CNG support for SHA1
Edward Thomson 603bee07 2012-11-12T19:22:49 Remove git_hash_ctx_new - callers now _ctx_init()
Russell Belfer 744cc03e 2012-10-30T12:10:36 Add git_config_refresh() API to reload config This adds a new API that allows users to reload the config if the file has changed on disk. A new config callback function to refresh the config was added. The modified time and file size are used to test if the file needs to be reloaded (and are now stored in the disk backend object). In writing tests, just using mtime was a problem / race, so I wanted to check file size as well. To support that, I extended `git_futils_readbuffer_updated` to optionally check file size in addition to mtime, and I added a new function `git_filebuf_stats` to fetch the mtime and size for an open filebuf (so that the config could be easily refreshed after a write). Lastly, I moved some similar file checking code for attributes into filebuf. It is still only being used for attrs, but it seems potentially reusable, so I thought I'd move it over.
Vicent Marti c859184b 2012-09-11T23:05:24 Properly handle p_reads
Russell Belfer 97a17e4e 2012-08-24T12:19:22 Fix valgrind warnings and spurious error messages Just clean up valgrind warnings about uninitialized memory and also clear out errno in some cases where it results in a false error message being generated at a later point.
Vicent Marti 5daca042 2012-08-03T01:01:21 filebuf: Check the return value for `close`
nulltoken 9bea8e85 2012-05-27T19:54:53 filebuf: add git_filebuf_flush()
Carlos Martín Nieto 4d53f3e2 2012-04-05T23:37:38 filebuf: add option not to buffer the contents at all The new indexer needs to be able to bypass any kind of buffering, as it's trying to map data that it has just written to disk.
Russell Belfer 0d0fa7c3 2012-03-16T15:56:01 Convert attr, ignore, mwindow, status to new errors Also cleaned up some previously converted code that still had little things to polish.
Russell Belfer e1de726c 2012-03-12T22:55:40 Migrate ODB files to new error handling This migrates odb.c, odb_loose.c, odb_pack.c and pack.c to the new style of error handling. Also got the unix and win32 versions of map.c. There are some minor changes to other files but no others were completely converted. This also contains an update to filebuf so that a zeroed out filebuf will not think that the fd (== 0) is actually open (and inadvertently call close() on fd 0 if cleaned up). Lastly, this was built and tested on win32 and contains a bunch of fixes for the win32 build which was pretty broken.
Vicent Martí dda708e7 2012-03-09T19:55:50 error-handling: On-disk config file backend Includes: - Proper error reporting when encountering syntax errors in a config file (file, line number, column). - Rewritten `config_write`, now with 99% less goto-spaghetti - Error state in `git_filebuf`: filebuf write functions no longer need to be checked for error returns. If any of the writes performed on a buffer fail, the last call to `git_filebuf_commit` or `git_filebuf_hash` will fail accordingly and set the appropiate error message. Baller!
Russell Belfer ae9e29fd 2012-03-06T16:14:31 Migrating diff to new error handling Ended up migrating a bunch of upstream functions as well including vector, attr_file, and odb in order to get this to work right.
Vicent Martí 1a481123 2012-02-17T00:13:34 error-handling: References Yes, this is error handling solely for `refs.c`, but some of the abstractions leak all ofer the code base.
Paul Betts 1db9d2c3 2012-02-23T17:11:20 Ensure that commits don't fail if committing content that already exists Making a commit that results in a blob that already exists in the ODB (i.e. committing something, then making a revert commit) will result in us trying to p_rename -> MoveFileExW a temp file into the existing ODB entry. Despite the MOVEFILE_REPLACE_EXISTING flag is passed in, Win32 does not care and fails it with STATUS_ACCESS_DENIED. To fix this, we p_unlink the ODB entry before attempting to rename it. This call will typically fail, but we don't care, we'll let the p_rename fail if the file actually does exist and we couldn't delete it for some reason (ACLs, etc).
schu 5e0de328 2012-02-13T17:10:24 Update Copyright header Signed-off-by: schu <schu-github@schulog.org>
Russell Belfer 1744fafe 2012-01-17T15:49:47 Move path related functions from fileops to path This takes all of the functions that look up simple data about paths (such as `git_futils_isdir`) and moves them over to path.h (becoming `git_path_isdir`). This leaves fileops.h just with functions that actually manipulate the filesystem or look at the file contents in some way. As part of this, the dir.h header which is really just for win32 support was moved into win32 (with some minor changes).
Russell Belfer 97769280 2011-11-30T11:27:15 Use git_buf for path storage instead of stack-based buffers This converts virtually all of the places that allocate GIT_PATH_MAX buffers on the stack for manipulating paths to use git_buf objects instead. The patch is pretty careful not to touch the public API for libgit2, so there are a few places that still use GIT_PATH_MAX. This extends and changes some details of the git_buf implementation to add a couple of extra functions and to make error handling easier. This includes serious alterations to all the path.c functions, and several of the fileops.c ones, too. Also, there are a number of new functions that parallel existing ones except that use a git_buf instead of a stack-based buffer (such as git_config_find_global_r that exists alongsize git_config_find_global). This also modifies the win32 version of p_realpath to allocate whatever buffer size is needed to accommodate the realpath instead of hardcoding a GIT_PATH_MAX limit, but that change needs to be tested still.
Russell Belfer b762e576 2011-11-17T15:10:27 filebuf: add GIT_FILEBUF_INIT and protect multiple opens and cleanups Update all stack allocations of git_filebuf to use GIT_FILEBUF_INIT and make git_filebuf_open and git_filebuf_cleanup safe to be called multiple times on the same buffer. Signed-off-by: Vicent Marti <tanoku@gmail.com>
Carlos Martín Nieto 0c49ec2d 2011-11-07T19:34:24 Implement p_rename Move the callers of git_futils_mv_atomic to use p_rename. Signed-off-by: Carlos Martín Nieto <carlos@cmartin.tk>
Vicent Martí 89fb8f02 2011-10-28T19:04:23 Merge pull request #456 from brodie/perm-fixes Create objects, indexes, and directories with the right file permissions
Vicent Marti 3286c408 2011-10-28T14:51:13 global: Properly use `git__` memory wrappers Ensure that all memory related functions (malloc, calloc, strdup, free, etc) are using their respective `git__` wrappers.
Brodie Rao 01ad7b3a 2011-09-06T15:48:45 *: correct and codify various file permissions The following files now have 0444 permissions: - loose objects - pack indexes - pack files - packs downloaded by fetch - packs downloaded by the HTTP transport And the following files now have 0666 permissions: - config files - repository indexes - reflogs - refs This brings libgit2 more in line with Git. Note that git_filebuf_commit() and git_filebuf_commit_at() have both gained a new mode parameter. The latter change fixes an important issue where filebufs created with GIT_FILEBUF_TEMPORARY received 0600 permissions (due to mkstemp(3) usage). Now we chmod() the file before renaming it into place. Tests have been added to confirm that new commit, tag, and tree objects are created with the right permissions. I don't have access to Windows, so for now I've guarded the tests with "#ifndef GIT_WIN32".
Brodie Rao ce8cd006 2011-09-07T15:32:44 fileops/repository: create (most) directories with 0777 permissions To further match how Git behaves, this change makes most of the directories libgit2 creates in a git repo have a file mode of 0777. Specifically: - Intermediate directories created with git_futils_mkpath2file() have 0777 permissions. This affects odb_loose, reflog, and refs. - The top level folder for bare repos is created with 0777 permissions. - The top level folder for non-bare repos is created with 0755 permissions. - /objects/info/, /objects/pack/, /refs/heads/, and /refs/tags/ are created with 0777 permissions. Additionally, the following changes have been made: - fileops functions that create intermediate directories have grown a new dirmode parameter. The only exception to this is filebuf's lock_file(), which unconditionally creates intermediate directories with 0777 permissions when GIT_FILEBUF_FORCE is set. - The test runner now sets the umask to 0 before running any tests. This ensurses all file mode checks are consistent across systems. - t09-tree.c now does a directory permissions check. I've avoided adding this check to other tests that might reuse existing directories from the prefabricated test repos. Because they're checked into the repo, they have 0755 permissions. - Other assorted directories created by tests have 0777 permissions.
Vicent Marti c103d7b4 2011-09-29T15:49:28 odb: Pass compression settings to filebuf
Vicent Martí 3125929b 2011-09-18T19:54:18 Merge pull request #393 from schu/unused-but-set-variable filebuf.c: fix unused-but-set warning
Vicent Marti bb742ede 2011-09-19T01:54:32 Cleanup legal data 1. The license header is technically not valid if it doesn't have a copyright signature. 2. The COPYING file has been updated with the different licenses used in the project. 3. The full GPLv2 header in each file annoys me.
schu c8f16bfe 2011-09-09T14:05:32 filebuf.c: fix unused-but-set warning write_deflate() used to ignore errors by zlib's deflate function when not compiling in DEBUG mode. Always read $result and throw an error instead. Signed-off-by: schu <schu-github@schulog.org>
Sebastian Schuberth 1c3fac4d 2011-09-08T14:31:37 Add casts to get rid of some warnings when filling zlib structures
Sebastian Schuberth 353560b4 2011-09-08T14:29:54 Get rid of a superfluous pointer cast
Sebastian Schuberth 45e93ef3 2011-09-08T14:22:29 Fix minor indentation issues (spaces to tabs)
Kirill A. Shutemov 05a62d1a 2011-07-18T05:11:18 filebuf: update git_filebuf.write signature to take non-const buffer z_stream.next_in is non-const. Although currently Zlib doesn't modify buffer content on deflate(), it might be change in the future. gzwrite() already modify it. To avoid this let's change signature of git_filebuf.write and rework git_filebuf_write() accordingly. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Vicent Marti 2fc78e70 2011-07-08T23:01:37 posix: Portable `vsnprintf` Our good, lovely folks at Microsoft decided that there was no good reason to make `vsnprintf` compilant with the C standard, so that function in Windows returns -1 on overflow, instead of returning the actual byte count needed to write the full string. We now handle this situation more gracefully with the POSIX compatibility layer, by returning the needed byte size using an auxiliary method instead of blindly resizing the target buffer until it fits. This means we can now support `printf`s of any size by allocating a temporary buffer. That's good.
Vicent Marti afeecf4f 2011-07-09T02:10:46 odb: Direct writes are back DIRECT WRITES ARE BACK AND FASTER THAN EVER. The streaming writer to the ODB was an overkill for the smaller objects like Commit and Tags; most of the streaming logic was taking too long. This commit makes Commits, Tags and Trees to be built-up in memory, and then written to disk in 2 pushes (header + data), instead of streaming everything. This is *always* faster, even for big files (since the git_filebuf class still does streaming writes when the memory cache overflows). This is also a gazillion lines of code smaller, because we don't have to precompute the final size of the object before starting the stream (this was kind of defeating the point of streaming, anyway). Blobs are still written with full streaming instead of loading them in memory, since this is still the fastest way. A new `git_buf` class has been added. It's missing some features, but it'll get there.
Vicent Marti f79026b4 2011-07-04T11:43:34 fileops: Cleanup Cleaned up the structure of the whole OS-abstraction layer. fileops.c now contains a set of utility methods for file management used by the library. These are abstractions on top of the original POSIX calls. There's a new file called `posix.c` that contains emulations/reimplementations of all the POSIX calls the library uses. These are prefixed with `p_`. There's a specific posix file for each platform (win32 and unix). All the path-related methods have been moved from `utils.c` to `path.c` and have their own prefix.
Kirill A. Shutemov 932d1baf 2011-06-30T19:52:34 cleanup: remove trailing spaces Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Kirill A. Shutemov fe5babac 2011-06-30T00:16:23 filebuf: fix endless loop on writing buf > WRITE_BUFFER_SIZE Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Carlos Martín Nieto bb9272dd 2011-06-07T17:03:07 filebuf cleanup: only unlink lockfile if we've opened it Add a check for the file descriptor in git_filebuf_cleanup. Without it, an existing lockfile would be deleted if we tried to acquire it (but failed, as the lockfile already existed). Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
Vicent Marti f9213015 2011-06-06T01:54:59 filebuf: Fix printf buffer overflows The filebuf was not being properly written after a flush. This should cut it now. Fixes #228
Romain Geissler 1549cba9 2011-06-03T21:18:24 Filebuf: Fixed a TODO in filebuf (real lock in lock_file) Added gitfo_creat_locked and gitfo_creat_locked_force
Vicent Marti f6328611 2011-05-23T21:00:19 filebuf: Reword errors
Jakob Pfender 374db5f9 2011-05-17T17:43:00 filebuf.c: Move to new error handling mechanism
Vicent Marti a6359408 2011-04-10T12:23:55 Use Z_BEST_SPEED for filebuf deflating This is what Git uses by default for all deflating.
Vicent Marti f6f72d7e 2011-03-23T18:44:53 Improve the ODB writing backend Temporary files when doing streaming writes are now stored inside the Objects folder, to prevent issues when moving files between disks/partitions. Add support for block writes to the ODB again (for those backends that cannot implement streaming).
Vicent Marti 72a3fe42 2011-03-18T19:38:49 I broke your bindings Hey. Apologies in advance -- I broke your bindings. This is a major commit that includes a long-overdue redesign of the whole object-database structure. This is expected to be the last major external API redesign of the library until the first non-alpha release. Please get your bindings up to date with these changes. They will be included in the next minor release. Sorry again! Major features include: - Real caching and refcounting on parsed objects - Real caching and refcounting on objects read from the ODB - Streaming writes & reads from the ODB - Single-method writes for all object types - The external API is now partially thread-safe The speed increases are significant in all aspects, specially when reading an object several times from the ODB (revwalking) and when writing big objects to the ODB. Here's a full changelog for the external API: blob.h ------ - Remove `git_blob_new` - Remove `git_blob_set_rawcontent` - Remove `git_blob_set_rawcontent_fromfile` - Rename `git_blob_writefile` -> `git_blob_create_fromfile` - Change `git_blob_create_fromfile`: The `path` argument is now relative to the repository's working dir - Add `git_blob_create_frombuffer` commit.h -------- - Remove `git_commit_new` - Remove `git_commit_add_parent` - Remove `git_commit_set_message` - Remove `git_commit_set_committer` - Remove `git_commit_set_author` - Remove `git_commit_set_tree` - Add `git_commit_create` - Add `git_commit_create_v` - Add `git_commit_create_o` - Add `git_commit_create_ov` tag.h ----- - Remove `git_tag_new` - Remove `git_tag_set_target` - Remove `git_tag_set_name` - Remove `git_tag_set_tagger` - Remove `git_tag_set_message` - Add `git_tag_create` - Add `git_tag_create_o` tree.h ------ - Change `git_tree_entry_2object`: New signature is `(git_object **object_out, git_repository *repo, git_tree_entry *entry)` - Remove `git_tree_new` - Remove `git_tree_add_entry` - Remove `git_tree_remove_entry_byindex` - Remove `git_tree_remove_entry_byname` - Remove `git_tree_clearentries` - Remove `git_tree_entry_set_id` - Remove `git_tree_entry_set_name` - Remove `git_tree_entry_set_attributes` object.h ------------ - Remove `git_object_new - Remove `git_object_write` - Change `git_object_close`: This method is now *mandatory*. Not closing an object causes a memory leak. odb.h ----- - Remove type `git_rawobj` - Remove `git_rawobj_close` - Rename `git_rawobj_hash` -> `git_odb_hash` - Change `git_odb_hash`: New signature is `(git_oid *id, const void *data, size_t len, git_otype type)` - Add type `git_odb_object` - Add `git_odb_object_close` - Change `git_odb_read`: New signature is `(git_odb_object **out, git_odb *db, const git_oid *id)` - Change `git_odb_read_header`: New signature is `(size_t *len_p, git_otype *type_p, git_odb *db, const git_oid *id)` - Remove `git_odb_write` - Add `git_odb_open_wstream` - Add `git_odb_open_rstream` odb_backend.h ------------- - Change type `git_odb_backend`: New internal signatures are as follows int (* read)(void **, size_t *, git_otype *, struct git_odb_backend *, const git_oid *) int (* read_header)(size_t *, git_otype *, struct git_odb_backend *, const git_oid *) int (* writestream)(struct git_odb_stream **, struct git_odb_backend *, size_t, git_otype) int (* readstream)( struct git_odb_stream **, struct git_odb_backend *, const git_oid *) - Add type `git_odb_stream` - Add enum `git_odb_streammode` Signed-off-by: Vicent Marti <tanoku@gmail.com>
Vicent Marti 55ffebe3 2011-03-05T14:34:32 Fix creation of deeply-rooted references Use a new `gitfo_creat_force` that will create the full path to a file before creating it. Signed-off-by: Vicent Marti <tanoku@gmail.com>
Vicent Marti 19a30a3f 2011-03-03T19:53:17 Add new move function, `gitfo_mv_force` Forces a move by creating the folder for the destination file, if it doesn't exist. Signed-off-by: Vicent Marti <tanoku@gmail.com>
Vicent Marti 86194b24 2011-02-18T21:57:53 Split packed from unpacked references These two reference types are now stored separately to eventually allow the removal/renaming of loose references and rewriting of the refs packfile. Signed-off-by: Vicent Marti <tanoku@gmail.com>
Vicent Marti c3be1468 2011-02-24T19:31:12 Fix double-freeing file descriptors Was crashing the Windows build. Signed-off-by: Vicent Marti <tanoku@gmail.com>
Vicent Marti 5591ea15 2011-02-22T14:58:54 Add printf method to the File Buffer Signed-off-by: Vicent Marti <tanoku@gmail.com>
Vicent Marti 817c2820 2011-02-21T17:05:16 Rewrite all file IO for more performance The new `git_filebuf` structure provides atomic high-performance writes to disk by using a write cache, and optionally a double-buffered scheme through a worker thread (not enabled yet). Writes can be done 3-layered, like in git.git (user code -> write cache -> disk), or 2-layered, by writing directly on the cache. This makes index writing considerably faster. The `git_filebuf` structure contains all the old functionality of `git_filelock` for atomic file writes and reads. The `git_filelock` structure has been removed. Additionally, the `git_filebuf` API allows to automatically hash (SHA1) all the data as it is written to disk (hashing is done smartly on big chunks to improve performance). Signed-off-by: Vicent Marti <tanoku@gmail.com>