user/sven/git.git/diffcore.h, branch v1.5.4.4

copy vs rename detection: avoid unnecessary O(n*m) loops

2007-10-27T06:18:06Z

The core rename detection had some rather stupid code to check if a pathname was used by a later modification or rename, which basically walked the whole pathname space for all renames for each rename, in order to tell whether it was a pure rename (no remaining users) or should be considered a copy (other users of the source file remaining). That's really silly, since we can just keep a count of users around, and replace all those complex and expensive loops with just testing that simple counter (but this all depends on the previous commit that shared the diff_filespec data structure by using a separate reference count). Note that the reference count is not the same as the rename count: they behave otherwise rather similarly, but the reference count is tied to the allocation (and decremented at de-allocation, so that when it turns zero we can get rid of the memory), while the rename count is tied to the renames and is decremented when we find a rename (so that when it turns zero we know that it was a rename, not a copy). Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

Ref-count the filespecs used by diffcore

2007-10-27T06:18:05Z

Rather than copy the filespecs when introducing new versions of them (for rename or copy detection), use a refcount and increment the count when reusing the diff_filespec. This avoids unnecessary allocations, but the real reason behind this is a future enhancement: we will want to track shared data across the copy/rename detection. In order to efficiently notice when a filespec is used by a rename, the rename machinery wants to keep track of a rename usage count which is shared across all different users of the filespec. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano

rename diff_free_filespec_data_large() to diff_free_filespec_blob()

2007-10-03T04:02:09Z

Signed-off-by: Junio C Hamano

diffcore-rename: cache file deltas

2007-10-03T04:02:03Z

We find rename candidates by computing a fingerprint hash of each file, and then comparing those fingerprints. There are inherently O(n^2) comparisons, so it pays in CPU time to hoist the (rather expensive) computation of the fingerprint out of that loop (or to cache it once we have computed it once). Previously, we didn't keep the filespec information around because then we had the potential to consume a great deal of memory. However, instead of keeping all of the filespec data, we can instead just keep the fingerprint. This patch implements and uses diff_free_filespec_data_large to accomplish that goal. We also have to change estimate_similarity not to needlessly repopulate the filespec data when we already have the hash. Practical tests showed 4.5x speedup for a 10% memory usage increase. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Fix configuration syntax to specify customized hunk header patterns.

2007-07-07T08:49:58Z

This updates the hunk header customization syntax. The special case 'funcname' attribute is gone. You assign the name of the type of contents to path's "diff" attribute as a string value in .gitattributes like this: *.java diff=java *.perl diff=perl *.doc diff=doc If you supply "diff..funcname" variable via the configuration mechanism (e.g. in $HOME/.gitconfig), the value is used as the regexp set to find the line to use for the hunk header (the variable is called "funcname" because such a line typically is the one that has the name of the function in programming language source text). If there is no such configuration, built-in default is used, if any. Currently there are two default patterns: default and java. Signed-off-by: Junio C Hamano

Per-path attribute based hunk header selection.

2007-07-06T08:20:47Z

This makes"diff -p" hunk headers customizable via gitattributes mechanism. It is based on Johannes's earlier patch that allowed to define a single regexp to be used for everything. The mechanism to arrive at the regexp that is used to define hunk header is the same as other use of gitattributes. You assign an attribute, funcname (because "diff -p" typically uses the name of the function the patch is about as the hunk header), a simple string value. This can be one of the names of built-in pattern (currently, "java" is defined) or a custom pattern name, to be looked up from the configuration file. (in .gitattributes) *.java funcname=java *.perl funcname=perl (in .git/config) [funcname] java = ... # ugly and complicated regexp to override the built-in one. perl = ... # another ugly and complicated regexp to define a new one. Signed-off-by: Junio C Hamano

Introduce diff_filespec_is_binary()

2007-07-06T07:21:41Z

This replaces an explicit initialization of filespec->is_binary field used for rename/break followed by direct access to that field with a wrapper function that lazily iniaitlizes and accesses the field. We would add more attribute accesses for the use of diff routines, and it would be better to make this abstraction earlier. Signed-off-by: Junio C Hamano

diffcore_filespec: add is_binary

2007-07-01T03:51:31Z

diffcore-break and diffcore-rename would want to behave slightly differently depending on the binary-ness of the data, so add one bit to the filespec, as the structure is now passed down to diffcore_count_changes() function. Signed-off-by: Junio C Hamano

diffcore_count_changes: pass diffcore_filespec

2007-07-01T03:51:31Z

We may want to use richer information on the data we are dealing with in this function, so instead of passing a buffer address and length, just pass the diffcore_filespec structure. Existing callers always call this function with parameters taken from a filespec anyway, so there is no functionality changes. Signed-off-by: Junio C Hamano

Make macros to prevent double-inclusion in headers consistent.

2007-04-29T09:05:11Z

Signed-off-by: Junio C Hamano