Support hashing objects larger than 4GB on Windows#2138
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On LLP64 systems, such as Windows, the size of `long`, `int`, etc. is only 32 bits (for backward compatibility). Git's use of `unsigned long` for file memory sizes in many places, rather than size_t, limits the handling of large files on LLP64 systems (commonly given as `>4GB`). Provide a minimum test for handling a >4GB file. The `hash-object` command, with the `--literally` and without `-w` option avoids writing the object, either loose or packed. This avoids the code paths hitting the `bigFileThreshold` config test code, the zlib code, and the pack code. Subsequent patches will walk the test's call chain, converting types to `size_t` (which is larger in LLP64 data models) where appropriate. Signed-off-by: Philip Oakley <philipoakley@iee.email> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Continue walking the code path for the >4GB `hash-object --literally` test. The `hash_object_file_literally()` function internally uses both `hash_object_file()` and `write_object_file_prepare()`. Both function signatures use `unsigned long` rather than `size_t` for the mem buffer sizes. Use `size_t` instead, for LLP64 compatibility. While at it, convert those function's object's header buffer length to `size_t` for consistency. The value is already upcast to `uintmax_t` for print format compatibility. Note: The hash-object test still does not pass. A subsequent commit continues to walk the call tree's lower level hash functions to identify further fixes. Signed-off-by: Philip Oakley <philipoakley@iee.email> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Continue walking the code path for the >4GB `hash-object --literally`
test to the hash algorithm step for LLP64 systems.
This patch lets the SHA1DC code use `size_t`, making it compatible with
LLP64 data models (as used e.g. by Windows).
The interested reader of this patch will note that we adjust the
signature of the `git_SHA1DCUpdate()` function without updating _any_
call site. This certainly puzzled at least one reviewer already, so here
is an explanation:
This function is never called directly, but always via the macro
`platform_SHA1_Update`, which is usually called via the macro
`git_SHA1_Update`. However, we never call `git_SHA1_Update()` directly
in `struct git_hash_algo`. Instead, we call `git_hash_sha1_update()`,
which is defined thusly:
static void git_hash_sha1_update(git_hash_ctx *ctx,
const void *data, size_t len)
{
git_SHA1_Update(&ctx->sha1, data, len);
}
i.e. it contains an implicit downcast from `size_t` to `unsigned long`
(before this here patch). With this patch, there is no downcast anymore.
With this patch, finally, the t1007-hash-object.sh "files over 4GB hash
literally" test case is fixed.
Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Just like the `hash-object --literally` code path, the `--stdin` code path also needs to use `size_t` instead of `unsigned long` to represent memory sizes, otherwise it would cause problems on platforms using the LLP64 data model (such as Windows). To limit the scope of the test case, the object is explicitly not written to the object store, nor are any filters applied. The `big` file from the previous test case is reused to save setup time; To avoid relying on that side effect, it is generated if it does not exist (e.g. when running via `sh t1007-*.sh --long --run=1,41`). Signed-off-by: Philip Oakley <philipoakley@iee.email> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
To complement the `--stdin` and `--literally` test cases that verify that we can hash files larger than 4GB on 64-bit platforms using the LLP64 data model, here is a test case that exercises `hash-object` _without_ any options. Just as before, we use the `big` file from the previous test case if it exists to save on setup time, otherwise generate it. Signed-off-by: Philip Oakley <philipoakley@iee.email> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
To verify that the `clean` side of the `clean`/`smudge` filter code is correct with regards to LLP64 (read: to ensure that `size_t` is used instead of `unsigned long`), here is a test case using a trivial filter, specifically _not_ writing anything to the object store to limit the scope of the test case. As in previous commits, the `big` file from previous test cases is reused if available, to save setup time, otherwise re-generated. Signed-off-by: Philip Oakley <philipoakley@iee.email> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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Philip Oakley has contributed these patches ~4.5 years ago, and they have been carried in Git for Windows ever since.
Now that there are already other patch series flying around that try to address various aspects about >4GB objects (which aren't handled well by Git until it stops forcing
unsigned longto dosize_t's job), it seems a good time to upstream these patches, too, at long last.