user/sven/git.git/replace-object.h, branch v2.26.0-rc2

replace-object: make replace operations thread-safe

2020-01-17T21:52:14Z

replace-object functions are very close to being thread-safe: the only current racy section is the lazy initialization at prepare_replace_object(). The following patches will protect some object reading operations to be called threaded, but before that, replace functions must be protected. To do so, add a mutex to struct raw_object_store and acquire it before lazy initializing the replace_map. This won't cause any noticeable performance drop as the mutex will no longer be used after the replace_map is initialized. Later, when the replace functions are called in parallel, thread debuggers might point our use of the added replace_map_initialized flag as a data race. However, as this boolean variable is initialized as false and it's only updated once, there's no real harm. It's perfectly fine if the value is updated right after a thread read it in replace-map.h:lookup_replace_object() (there'll only be a performance penalty for the affected threads at that moment). We could cease the debugger warning protecting the variable reading at the said function. However, this would negatively affect performance for all threads calling it, at any time, so it's not really worthy since the warning doesn't represent a real problem. Instead, to make sure we don't get false positives (at ThreadSanitizer, at least) an entry for the respective function is added to .tsan-suppressions. Signed-off-by: Matheus Tavares Signed-off-by: Junio C Hamano

*.[ch]: manually align parameter lists

2019-05-05T06:20:10Z

In previous patches, extern was mechanically removed from function declarations without care to formatting, causing parameter lists to be misaligned. Manually format changed sections such that the parameter lists should be realigned. Viewing this patch with 'git diff -w' should produce no output. Signed-off-by: Denton Liu Signed-off-by: Junio C Hamano

*.[ch]: remove extern from function declarations using spatch

2019-05-05T06:20:06Z

There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu Signed-off-by: Junio C Hamano

commit-graph: not compatible with replace objects

2018-08-21T17:22:51Z

Create new method commit_graph_compatible(r) to check if a given repository r is compatible with the commit-graph feature. Fill the method with a check to see if replace-objects exist. Test this interaction succeeds, including ignoring an existing commit-graph and failing to write a new commit-graph. However, we do ensure that we write a new commit-graph by setting read_replace_refs to 0, thereby ignoring the replace refs. Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

check_replace_refs: rename to read_replace_refs

2018-07-18T22:45:14Z

This was added as a NEEDSWORK in c3c36d7de2 (replace-object: check_replace_refs is safe in multi repo environment, 2018-04-11), waiting for a calmer period. Since doing so now doesn't conflict with anything in 'pu', it seems as good a time as any. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

replace-object: allow lookup_replace_object to handle arbitrary repositories

2018-04-12T02:38:57Z

Signed-off-by: Stefan Beller Signed-off-by: Junio C Hamano

replace-object: allow do_lookup_replace_object to handle arbitrary repositories

2018-04-12T02:38:57Z

Signed-off-by: Stefan Beller Signed-off-by: Junio C Hamano

replace-object: add repository argument to lookup_replace_object

2018-04-12T02:38:56Z

Add a repository argument to allow callers of lookup_replace_object to be more specific about which repository to handle. This is a small mechanical change; it doesn't change the implementation to handle repositories other than the_repository yet. As with the previous commits, use a macro to catch callers passing a repository other than the_repository at compile time. Signed-off-by: Jonathan Nieder Signed-off-by: Stefan Beller Signed-off-by: Junio C Hamano

replace-object: add repository argument to do_lookup_replace_object

2018-04-12T02:38:56Z

Add a repository argument to allow the do_lookup_replace_object caller to be more specific about which repository to handle. This is a small mechanical change; it doesn't change the implementation to handle repositories other than the_repository yet. As with the previous commits, use a macro to catch callers passing a repository other than the_repository at compile time. Signed-off-by: Jonathan Nieder Signed-off-by: Stefan Beller Signed-off-by: Junio C Hamano

replace-object: check_replace_refs is safe in multi repo environment

2018-04-12T02:38:56Z

In e1111cef23 (inline lookup_replace_object() calls, 2011-05-15) a shortcut for checking the object replacement was added by setting check_replace_refs to 0 once the replacements were evaluated to not exist. This works fine in with the assumption of only one repository in existence. The assumption won't hold true any more when we work on multiple instances of a repository structs (e.g. one struct per submodule), as the first repository to be inspected may have no replacements and would set the global variable. Other repositories would then completely omit their evaluation of replacements. This reverts back the meaning of the flag `check_replace_refs` of "Do we need to check with the lookup table?" to "Do we need to read the replacement definition?", adding the bypassing logic to lookup_replace_object after the replacement definition was read. As with the original patch, delay the renaming of the global variable Signed-off-by: Stefan Beller Signed-off-by: Junio C Hamano