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* Merge branch 'jk/avoid-unbounded-alloca' into maintJunio C Hamano2016-07-06
|\ | | | | | | | | | | | | | | A codepath that used alloca(3) to place an unbounded amount of data on the stack has been updated to avoid doing so. * jk/avoid-unbounded-alloca: tree-diff: avoid alloca for large allocations
| * tree-diff: avoid alloca for large allocationsJeff King2016-06-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 72441af (tree-diff: rework diff_tree() to generate diffs for multiparent cases as well, 2014-04-07) introduced the use of alloca so that the common cases of commits with 1 or 2 parents would not be adversely affected by going through the multi-parent code. However, our xalloca is not ideal when the number of parents grows very large: 1. If the requested size is too large for our stack, alloca() has no way to tell us, and we simply segfault while trying to access the memory. 2. It does not use our usual memory_limit_check() logic. I measured, and alloca is indeed buying us a very small speedup over xmalloc()/free(). So we'd want to keep something like it. This patch simply puts a conditional in place at each callsite: we use alloca for common known-small numbers of parents, and otherwise use the heap. We are technically still vulnerable to (1), but no more so than if we simply put a few dozen bytes on the stack, which we must do all the time anyway. And likewise, we technically miss a memory limit check if it is tiny, but such a limit is pointless. An alternative to this would be implement something like: struct tree *tp, tp_fallback[2]; if (nparent <= ARRAY_SIZE(tp_fallback)) tp = tp_fallback; else ALLOC_ARRAY(tp, nparent); ... if (tp != tp_fallback) free(tp); That would let us drop our xalloca() portability code entirely. But in my measurements, this seemed to perform slightly worse than the xalloca solution. Note in the example above, and in the patch below, I've used ALLOC_ARRAY() to replace the manual xmalloc(nr * sizeof(*x)). Besides being shorter, this has the bonus that one cannot accidentally overflow a size_t during that computation. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * tree-diff: catch integer overflow in combine_diff_path allocationJeff King2016-03-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | A combine_diff_path struct has two "flex" members allocated alongside the struct: a string to hold the pathname, and an array of parent pointers. We use an "int" to compute this, meaning we may easily overflow it if the pathname is extremely long. We can fix this by using size_t, and checking for overflow with the st_add helper. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | tree-walk: convert tree_entry_extract() to use struct object_idbrian m. carlson2016-04-25
| | | | | | | | | | Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | struct name_entry: use struct object_id instead of unsigned char sha1[20]brian m. carlson2016-04-25
| | | | | | | | | | Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | tree-diff: catch integer overflow in combine_diff_path allocationJeff King2016-02-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | A combine_diff_path struct has two "flex" members allocated alongside the struct: a string to hold the pathname, and an array of parent pointers. We use an "int" to compute this, meaning we may easily overflow it if the pathname is extremely long. We can fix this by using size_t, and checking for overflow with the st_add helper. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | diff: convert struct combine_diff_path to object_idbrian m. carlson2015-03-13
|/ | | | | | | Also, convert a constant to GIT_SHA1_HEXSZ. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: rework diff_tree() to generate diffs for multiparent cases as wellKirill Smelkov2014-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously diff_tree(), which is now named ll_diff_tree_sha1(), was generating diff_filepair(s) for two trees t1 and t2, and that was usually used for a commit as t1=HEAD~, and t2=HEAD - i.e. to see changes a commit introduces. In Git, however, we have fundamentally built flexibility in that a commit can have many parents - 1 for a plain commit, 2 for a simple merge, but also more than 2 for merging several heads at once. For merges there is a so called combine-diff, which shows diff, a merge introduces by itself, omitting changes done by any parent. That works through first finding paths, that are different to all parents, and then showing generalized diff, with separate columns for +/- for each parent. The code lives in combine-diff.c . There is an impedance mismatch, however, in that a commit could generally have any number of parents, and that while diffing trees, we divide cases for 2-tree diffs and more-than-2-tree diffs. I mean there is no special casing for multiple parents commits in e.g. revision-walker . That impedance mismatch *hurts* *performance* *badly* for generating combined diffs - in "combine-diff: optimize combine_diff_path sets intersection" I've already removed some slowness from it, but from the timings provided there, it could be seen, that combined diffs still cost more than an order of magnitude more cpu time, compared to diff for usual commits, and that would only be an optimistic estimate, if we take into account that for e.g. linux.git there is only one merge for several dozens of plain commits. That slowness comes from the fact that currently, while generating combined diff, a lot of time is spent computing diff(commit,commit^2) just to only then intersect that huge diff to almost small set of files from diff(commit,commit^1). That's because at present, to compute combine-diff, for first finding paths, that "every parent touches", we use the following combine-diff property/definition: D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn) (w.r.t. paths) where D(A,P1...Pn) is combined diff between commit A, and parents Pi and D(A,Pi) is usual two-tree diff Pi..A So if any of that D(A,Pi) is huge, tracting 1 n-parent combine-diff as n 1-parent diffs and intersecting results will be slow. And usually, for linux.git and other topic-based workflows, that D(A,P2) is huge, because, if merge-base of A and P2, is several dozens of merges (from A, via first parent) below, that D(A,P2) will be diffing sum of merges from several subsystems to 1 subsystem. The solution is to avoid computing n 1-parent diffs, and to find changed-to-all-parents paths via scanning A's and all Pi's trees simultaneously, at each step comparing their entries, and based on that comparison, populate paths result, and deduce we could *skip* *recursing* into subdirectories, if at least for 1 parent, sha1 of that dir tree is the same as in A. That would save us from doing significant amount of needless work. Such approach is very similar to what diff_tree() does, only there we deal with scanning only 2 trees simultaneously, and for n+1 tree, the logic is a bit more complex: D(T,P1...Pn) calculation scheme ------------------------------- D(T,P1...Pn) = D(T,P1) ^ ... ^ D(T,Pn) (regarding resulting paths set) D(T,Pj) - diff between T..Pj D(T,P1...Pn) - combined diff from T to parents P1,...,Pn We start from all trees, which are sorted, and compare their entries in lock-step: T P1 Pn - - - |t| |p1| |pn| |-| |--| ... |--| imin = argmin(p1...pn) | | | | | | |-| |--| |--| |.| |. | |. | . . . . . . at any time there could be 3 cases: 1) t < p[imin]; 2) t > p[imin]; 3) t = p[imin]. Schematic deduction of what every case means, and what to do, follows: 1) t < p[imin] -> ∀j t ∉ Pj -> "+t" ∈ D(T,Pj) -> D += "+t"; t↓ 2) t > p[imin] 2.1) ∃j: pj > p[imin] -> "-p[imin]" ∉ D(T,Pj) -> D += ø; ∀ pi=p[imin] pi↓ 2.2) ∀i pi = p[imin] -> pi ∉ T -> "-pi" ∈ D(T,Pi) -> D += "-p[imin]"; ∀i pi↓ 3) t = p[imin] 3.1) ∃j: pj > p[imin] -> "+t" ∈ D(T,Pj) -> only pi=p[imin] remains to investigate 3.2) pi = p[imin] -> investigate δ(t,pi) | | v 3.1+3.2) looking at δ(t,pi) ∀i: pi=p[imin] - if all != ø -> ⎧δ(t,pi) - if pi=p[imin] -> D += ⎨ ⎩"+t" - if pi>p[imin] in any case t↓ ∀ pi=p[imin] pi↓ ~ For comparison, here is how diff_tree() works: D(A,B) calculation scheme ------------------------- A B - - |a| |b| a < b -> a ∉ B -> D(A,B) += +a a↓ |-| |-| a > b -> b ∉ A -> D(A,B) += -b b↓ | | | | a = b -> investigate δ(a,b) a↓ b↓ |-| |-| |.| |.| . . . . ~~~~~~~~ This patch generalizes diff tree-walker to work with arbitrary number of parents as described above - i.e. now there is a resulting tree t, and some parents trees tp[i] i=[0..nparent). The generalization builds on the fact that usual diff D(A,B) is by definition the same as combined diff D(A,[B]), so if we could rework the code for common case and make it be not slower for nparent=1 case, usual diff(t1,t2) generation will not be slower, and multiparent diff tree-walker would greatly benefit generating combine-diff. What we do is as follows: 1) diff tree-walker ll_diff_tree_sha1() is internally reworked to be a paths generator (new name diff_tree_paths()), with each generated path being `struct combine_diff_path` with info for path, new sha1,mode and for every parent which sha1,mode it was in it. 2) From that info, we can still generate usual diff queue with struct diff_filepairs, via "exporting" generated combine_diff_path, if we know we run for nparent=1 case. (see emit_diff() which is now named emit_diff_first_parent_only()) 3) In order for diff_can_quit_early(), which checks DIFF_OPT_TST(opt, HAS_CHANGES)) to work, that exporting have to be happening not in bulk, but incrementally, one diff path at a time. For such consumers, there is a new callback in diff_options introduced: ->pathchange(opt, struct combine_diff_path *) which, if set to !NULL, is called for every generated path. (see new compat ll_diff_tree_sha1() wrapper around new paths generator for setup) 4) The paths generation itself, is reworked from previous ll_diff_tree_sha1() code according to "D(A,P1...Pn) calculation scheme" provided above: On the start we allocate [nparent] arrays in place what was earlier just for one parent tree. then we just generalize loops, and comparison according to the algorithm. Some notes(*): 1) alloca(), for small arrays, is used for "runs not slower for nparent=1 case than before" goal - if we change it to xmalloc()/free() the timings get ~1% worse. For alloca() we use just-introduced xalloca/xalloca_free compatibility wrappers, so it should not be a portability problem. 2) For every parent tree, we need to keep a tag, whether entry from that parent equals to entry from minimal parent. For performance reasons I'm keeping that tag in entry's mode field in unused bit - see S_IFXMIN_NEQ. Not doing so, we'd need to alloca another [nparent] array, which hurts performance. 3) For emitted paths, memory could be reused, if we know the path was processed via callback and will not be needed later. We use efficient hand-made realloc-style path_appendnew(), that saves us from ~1-1.5% of potential additional slowdown. 4) goto(s) are used in several places, as the code executes a little bit faster with lowered register pressure. Also - we should now check for FIND_COPIES_HARDER not only when two entries names are the same, and their hashes are equal, but also for a case, when a path was removed from some of all parents having it. The reason is, if we don't, that path won't be emitted at all (see "a > xi" case), and we'll just skip it, and FIND_COPIES_HARDER wants all paths - with diff or without - to be emitted, to be later analyzed for being copies sources. The new check is only necessary for nparent >1, as for nparent=1 case xmin_eqtotal always =1 =nparent, and a path is always added to diff as removal. ~~~~~~~~ Timings for # without -c, i.e. testing only nparent=1 case `git log --raw --no-abbrev --no-renames` before and after the patch are as follows: navy.git linux.git v3.10..v3.11 before 0.611s 1.889s after 0.619s 1.907s slowdown 1.3% 0.9% This timings show we did no harm to usual diff(tree1,tree2) generation. From the table we can see that we actually did ~1% slowdown, but I think I've "earned" that 1% in the previous patch ("tree-diff: reuse base str(buf) memory on sub-tree recursion", HEAD~~) so for nparent=1 case, net timings stays approximately the same. The output also stayed the same. (*) If we revert 1)-4) to more usual techniques, for nparent=1 case, we'll get ~2-2.5% of additional slowdown, which I've tried to avoid, as "do no harm for nparent=1 case" rule. For linux.git, combined diff will run an order of magnitude faster and appropriate timings will be provided in the next commit, as we'll be taking advantage of the new diff tree-walker for combined-diff generation there. P.S. and combined diff is not some exotic/for-play-only stuff - for example for a program I write to represent Git archives as readonly filesystem, there is initial scan with `git log --reverse --raw --no-abbrev --no-renames -c` to extract log of what was created/changed when, as a result building a map {} sha1 -> in which commit (and date) a content was added that `-c` means also show combined diff for merges, and without them, if a merge is non-trivial (merges changes from two parents with both having separate changes to a file), or an evil one, the map will not be full, i.e. some valid sha1 would be absent from it. That case was my initial motivation for combined diffs speedup. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: reuse base str(buf) memory on sub-tree recursionKirill Smelkov2014-03-27
| | | | | | | | | | | | | | | | | | | | Instead of allocating it all the time for every subtree in ll_diff_tree_sha1, let's allocate it once in diff_tree_sha1, and then all callee just use it in stacking style, without memory allocations. This should be faster, and for me this change gives the following slight speedups for git log --raw --no-abbrev --no-renames --format='%H' navy.git linux.git v3.10..v3.11 before 0.618s 1.903s after 0.611s 1.889s speedup 1.1% 0.7% Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: no need to call "full" diff_tree_sha1 from show_path()Kirill Smelkov2014-03-27
| | | | | | | | | | | | | As described in previous commit, when recursing into sub-trees, we can use lower-level tree walker, since its interface is now sha1 based. The change is ok, because diff_tree_sha1() only invokes ll_diff_tree_sha1(), and also, if base is empty, try_to_follow_renames(). But base is not empty here, as we have added a path and '/' before recursing. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: rework diff_tree interface to be sha1 basedKirill Smelkov2014-03-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the next commit this will allow to reduce intermediate calls, when recursing into subtrees - at that stage we know only subtree sha1, and it is natural for tree walker to start from that phase. For now we do diff_tree show_path diff_tree_sha1 diff_tree ... and the change will allow to reduce it to diff_tree show_path diff_tree Also, it will allow to omit allocating strbuf for each subtree, and just reuse the common strbuf via playing with its len. The above-mentioned improvements go in the next 2 patches. The downside is that try_to_follow_renames(), if active, we cause re-reading of 2 initial trees, which was negligible based on my timings, and which is outweighed cogently by the upsides. NOTE To keep with the current interface and semantics, I needed to rename the function from diff_tree() to diff_tree_sha1(). As diff_tree_sha1() was already used, and the function we are talking here is its more low-level helper, let's use convention for prefixing such helpers with "ll_". So the final renaming is diff_tree() -> ll_diff_tree_sha1() Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: diff_tree() should now be staticKirill Smelkov2014-03-26
| | | | | | | | | | | We reworked all its users to use the functionality through diff_tree_sha1 variant in recent patches (see "tree-diff: allow diff_tree_sha1 to accept NULL sha1" and what comes next). diff_tree() is now not used outside tree-diff.c - make it static. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: remove special-case diff-emitting code for empty-tree casesKirill Smelkov2014-03-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While walking trees, we iterate their entries from lowest to highest in sort order, so empty tree means all entries were already went over. If we artificially assign +infinity value to such tree "entry", it will go after all usual entries, and through the usual driver loop we will be taking the same actions, which were hand-coded for special cases, i.e. t1 empty, t2 non-empty pathcmp(+∞, t2) -> +1 show_path(/*t1=*/NULL, t2); /* = t1 > t2 case in main loop */ t1 non-empty, t2-empty pathcmp(t1, +∞) -> -1 show_path(t1, /*t2=*/NULL); /* = t1 < t2 case in main loop */ In other words when we have t1 and t2, we return a sign that tells the caller to indicate the "earlier" one to be emitted, and by returning the sign that causes the non-empty side to be emitted, we will automatically cause the entries from the remaining side to be emitted, without attempting to touch the empty side at all. We can teach tree_entry_pathcmp() to pretend that an empty tree has an element that sorts after anything else to achieve this. Right now we never go to when compared tree descriptors are both infinity, as this condition is checked in the loop beginning as finishing criteria, but will do so in the future, when there will be several parents iterated simultaneously, and some pair of them would run to the end. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: simplify tree_entry_pathcmpKirill Smelkov2014-03-20
| | | | | | | | | | | | | Since an earlier "Finally switch over tree descriptors to contain a pre-parsed entry", we can safely access all tree_desc->entry fields directly instead of first "extracting" them through tree_entry_extract. Use it. The code generated stays the same - only it now visually looks cleaner. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: show_path prototype is not needed anymoreKirill Smelkov2014-03-20
| | | | | | | | We moved all action-taking code below show_path() in recent HEAD~~ (tree-diff: move all action-taking code out of compare_tree_entry). Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: rename compare_tree_entry -> tree_entry_pathcmpKirill Smelkov2014-03-20
| | | | | | | | | | | | Since previous commit, this function does not compare entry hashes, and mode are compared fully outside of it. So what it does is compare entry names and DIR bit in modes. Reflect this in its name. Add documentation stating the semantics, and move the note about files/dirs comparison to it. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: move all action-taking code out of compare_tree_entry()Kirill Smelkov2014-03-20
| | | | | | | | | | | | | | - let it do only comparison. This way the code is cleaner and more structured - cmp function only compares, and the driver takes action based on comparison result. There should be no change in performance, as effectively, we just move if series from on place into another, and merge it to was-already-there same switch/if, so the result is maybe a little bit faster. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: don't assume compare_tree_entry() returns -1,0,1Kirill Smelkov2014-03-20
| | | | | | | | | | | | | | | | | | | | | | It does, but we'll be reworking it in the next patch after it won't, and besides it is better to stick to standard strcmp/memcmp/base_name_compare/etc... convention, where comparison function returns <0, =0, >0 Regarding performance, comparing for <0, =0, >0 should be a little bit faster, than switch, because it is just 1 test-without-immediate instruction and then up to 3 conditional branches, and in switch you have up to 3 tests with immediate and up to 3 conditional branches. No worry, that update_tree_entry(t2) is duplicated for =0 and >0 - it will be good after we'll be adding support for multiparent walker and will stay that way. =0 case goes first, because it happens more often in real diffs - i.e. paths are the same. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: consolidate code for emitting diffs and recursion in one placeKirill Smelkov2014-03-20
| | | | | | | | | | | | | | | | | | | | | | | | | | Currently both compare_tree_entry() and show_entry() invoke opt diff callbacks (opt->add_remove() and opt->change()), and also they both have code which decides whether to recurse into sub-tree, and whether to emit a tree as separate entry if DIFF_OPT_TREE_IN_RECURSIVE is set. I.e. we have code duplication and logic scattered on two places. Let's consolidate it - all diff emiting code and recurion logic moves to show_entry, which is now named as show_path, because it shows diff for a path, based on up to two tree entries, with actual diff emitting code being kept in new helper emit_diff() for clarity. What we have as the result, is that compare_tree_entry is now free from code with logic for diff generation, and also performance is not affected as timings for `git log --raw --no-abbrev --no-renames` for navy.git and `linux.git v3.10..v3.11`, just like in previous patch, stay the same. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: show_tree() is not neededKirill Smelkov2014-03-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't need special code for showing added/removed subtree, because we can do the same via diff_tree_sha1, just passing NULL for absent tree. And compared to show_tree(), which was calling show_entry() for every tree entry, that would lead to the same show_entry() callings: show_tree(t): for e in t.entries: show_entry(e) diff_tree_sha1(NULL, new): /* the same applies to (old, NULL) */ diff_tree(t1=NULL, t2) ... if (!t1->size) show_entry(t2) ... and possible overhead is negligible, since after the patch, timing for `git log --raw --no-abbrev --no-renames` for navy.git and `linux.git v3.10..v3.11` is practically the same. So let's say goodbye to show_tree() - it removes some code, but also, and what is important, consolidates more code for showing/recursing into trees into one place. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: no need to pass match to skip_uninteresting()Kirill Smelkov2014-02-24
| | | | | | | | It is neither used there as input, nor the output written through it, is used outside. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: no need to manually verify that there is no mode change for a pathKirill Smelkov2014-02-24
| | | | | | | | | | | | | | Because if there is, such two tree entries would never be compared as equal - the code in base_name_compare() explicitly compares modes, if there is a change for dir bit, even for equal paths, entries would compare as different. The code I'm removing here is from 2005 April 262e82b4 (Fix diff-tree recursion), which pre-dates base_name_compare() introduction in 958ba6c9 (Introduce "base_name_compare()" helper function) by a month. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: convert diff_root_tree_sha1() to just call diff_tree_sha1 with ↵Kirill Smelkov2014-02-05
| | | | | | | | | | | old=NULL Now since diff_tree_sha1 understands NULL for both old and new, we could indicate an empty tree for root commit by providing just NULL for old sha1. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: allow diff_tree_sha1 to accept NULL sha1Kirill Smelkov2014-02-05
| | | | | | | | | | | | | | which would mean that corresponding tree - old or new - is empty. As followup patches will show, that functionality was already needed in several places of Git codebase, but there, we were preparing empty tree_desc objects by hand, with some code duplication. For handling sha1 = NULL case, let's reuse fill_tree_descriptor() which returns just empty tree_desc in that case. Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* pathspec: stop --*-pathspecs impact on internal parse_pathspec() usesNguyễn Thái Ngọc Duy2013-10-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Normally parse_pathspec() is used on command line arguments where it can do fancy thing like parsing magic on each argument or adding magic for all pathspecs based on --*-pathspecs options. There's another use of parse_pathspec(), where pathspec is needed, but the input is known to be pure paths. In this case we usually don't want --*-pathspecs to interfere. And we definitely do not want to parse magic in these paths, regardless of --literal-pathspecs. Add new flag PATHSPEC_LITERAL_PATH for this purpose. When it's set, --*-pathspecs are ignored, no magic is parsed. And if the caller allows PATHSPEC_LITERAL (i.e. the next calls can take literal magic), then PATHSPEC_LITERAL will be set. This fixes cases where git chokes when GIT_*_PATHSPECS are set because parse_pathspec() indicates it won't take any magic. But GIT_*_PATHSPECS add them anyway. These are export GIT_LITERAL_PATHSPECS=1 git blame -- something git log --follow something git log --merge "git ls-files --with-tree=path" (aka parse_pathspec() in overlay_tree_on_cache()) is safe because the input is empty, and producing one pathspec due to PATHSPEC_PREFER_CWD does not take any magic into account. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Acked-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* pathspec: support :(literal) syntax for noglob pathspecNguyễn Thái Ngọc Duy2013-07-15
| | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-diff: remove the use of pathspec's raw[] in follow-rename codepathNguyễn Thái Ngọc Duy2013-07-15
| | | | | | | Put a checkpoint to guard unsupported pathspec features in future. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* remove init_pathspec() in favor of parse_pathspec()Nguyễn Thái Ngọc Duy2013-07-15
| | | | | | | While at there, move free_pathspec() to pathspec.c Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* remove diff_tree_{setup,release}_pathsNguyễn Thái Ngọc Duy2013-07-15
| | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* guard against new pathspec magic in pathspec matching codeNguyễn Thái Ngọc Duy2013-07-15
| | | | | | | | | | GUARD_PATHSPEC() marks pathspec-sensitive code, basically all those that touch anything in 'struct pathspec' except fields "nr" and "original". GUARD_PATHSPEC() is not supposed to fail. It's mainly to help the designers catch unsupported codepaths. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* parse_pathspec: add special flag for max_depth featureNguyễn Thái Ngọc Duy2013-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | match_pathspec_depth() and tree_entry_interesting() check max_depth field in order to support "git grep --max-depth". The feature activation is tied to "recursive" field, which led to some unwanted activation, e.g. 5c8eeb8 (diff-index: enable recursive pathspec matching in unpack_trees - 2012-01-15). This patch decouples the activation from "recursive" field, puts it in "magic" field instead. This makes sure that only "git grep" can activate this feature. And because parse_pathspec knows when the feature is not used, it does not need to sort pathspec (required for max_depth to work correctly). A small win for non-grep cases. Even though a new magic flag is introduced, no magic syntax is. The magic can be only enabled by parse_pathspec() caller. We might someday want to support ":(maxdepth:10)src." It all depends on actual use cases. max_depth feature cannot be enabled via init_pathspec() anymore. But that's ok because init_pathspec() is on its way to /dev/null. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'jk/maint-null-in-trees'Junio C Hamano2012-08-27
|\ | | | | | | | | | | | | | | | | We do not want a link to 0{40} object stored anywhere in our objects. * jk/maint-null-in-trees: fsck: detect null sha1 in tree entries do not write null sha1s to on-disk index diff: do not use null sha1 as a sentinel value
| * diff: do not use null sha1 as a sentinel valueJeff King2012-07-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The diff code represents paths using the diff_filespec struct. This struct has a sha1 to represent the sha1 of the content at that path, as well as a sha1_valid member which indicates whether its sha1 field is actually useful. If sha1_valid is not true, then the filespec represents a working tree file (e.g., for the no-index case, or for when the index is not up-to-date). The diff_filespec is only used internally, though. At the interfaces to the diff subsystem, callers feed the sha1 directly, and we create a diff_filespec from it. It's at that point that we look at the sha1 and decide whether it is valid or not; callers may pass the null sha1 as a sentinel value to indicate that it is not. We should not typically see the null sha1 coming from any other source (e.g., in the index itself, or from a tree). However, a corrupt tree might have a null sha1, which would cause "diff --patch" to accidentally diff the working tree version of a file instead of treating it as a blob. This patch extends the edges of the diff interface to accept a "sha1_valid" flag whenever we accept a sha1, and to use that flag when creating a filespec. In some cases, this means passing the flag through several layers, making the code change larger than would be desirable. One alternative would be to simply die() upon seeing corrupted trees with null sha1s. However, this fix more directly addresses the problem (while bogus sha1s in a tree are probably a bad thing, it is really the sentinel confusion sending us down the wrong code path that is what makes it devastating). And it means that git is more capable of examining and debugging these corrupted trees. For example, you can still "diff --raw" such a tree to find out when the bogus entry was introduced; you just cannot do a "--patch" diff (just as you could not with any other corrupted tree, as we do not have any content to diff). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | diff_setup_done(): return voidThomas Rast2012-08-03
|/ | | | | | | | | | | | | | | | | diff_setup_done() has historically returned an error code, but lost the last nonzero return in 943d5b7 (allow diff.renamelimit to be set regardless of -M/-C, 2006-08-09). The callers were in a pretty confused state: some actually checked for the return code, and some did not. Let it return void, and patch all callers to take this into account. This conveniently also gets rid of a handful of different(!) error messages that could never be triggered anyway. Note that the function can still die(). Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* use custom rename score during --followJeff King2011-12-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If you provide a custom rename score on the command line, like: git log -M50 --follow foo.c it is completely ignored, and there is no way to --follow with a looser rename score. Instead, let's use the same rename score that will be used for generating diffs. This is convenient, and mirrors what we do with the break-score. You can see an example of it being useful in git.git: $ git log --oneline --summary --follow \ Documentation/technical/api-string-list.txt 86d4b52 string-list: Add API to remove an item from an unsorted list 1d2f80f string_list: Fix argument order for string_list_append e242148 string-list: add unsorted_string_list_lookup() 0dda1d1 Fix two leftovers from path_list->string_list c455c87 Rename path_list to string_list create mode 100644 Documentation/technical/api-string-list.txt $ git log --oneline --summary -M40 --follow \ Documentation/technical/api-string-list.txt 86d4b52 string-list: Add API to remove an item from an unsorted list 1d2f80f string_list: Fix argument order for string_list_append e242148 string-list: add unsorted_string_list_lookup() 0dda1d1 Fix two leftovers from path_list->string_list c455c87 Rename path_list to string_list rename Documentation/technical/{api-path-list.txt => api-string-list.txt} (47%) 328a475 path-list documentation: document all functions and data structures 530e741 Start preparing the API documents. create mode 100644 Documentation/technical/api-path-list.txt You could have two separate rename scores, one for following and one for diff. But almost nobody is going to want that, and it would just be unnecessarily confusing. Besides which, we re-use the diff results from try_to_follow_renames for the actual diff output, which means having them as separate scores is actively wrong. E.g., with the current code, you get: $ git log --oneline --diff-filter=R --name-status \ -M90 --follow git.spec.in 27dedf0 GIT 0.99.9j aka 1.0rc3 R084 git-core.spec.in git.spec.in f85639c Rename the RPM from "git" to "git-core" R098 git.spec.in git-core.spec.in The first one should not be considered a rename by the -M score we gave, but we print it anyway, since we blindly re-use the diff information from the follow (which uses the default score). So this could also be considered simply a bug-fix, as with the current code "-M" is completely ignored when using "--follow". Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree_entry_interesting(): give meaningful names to return valuesNguyễn Thái Ngọc Duy2011-10-27
| | | | | | | | | It is a basic code hygiene to avoid magic constants that are unnamed. Besides, this helps extending the value later on for "interesting, but cannot decide if the entry truely matches yet" (ie. prefix matches) Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* tree-walk.c: do not leak internal structure in tree_entry_len()Nguyễn Thái Ngọc Duy2011-10-27
| | | | | | | | | | | | | tree_entry_len() does not simply take two random arguments and return a tree length. The two pointers must point to a tree item structure, or struct name_entry. Passing random pointers will return incorrect value. Force callers to pass struct name_entry instead of two pointers (with hope that they don't manually construct struct name_entry themselves) Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* Merge branch 'jk/diff-not-so-quick'Junio C Hamano2011-06-06
|\ | | | | | | | | | | | | | | | | * jk/diff-not-so-quick: diff: futureproof "stop feeding the backend early" logic diff_tree: disable QUICK optimization with diff filter Conflicts: diff.c
| * diff: futureproof "stop feeding the backend early" logicJunio C Hamano2011-05-31
| | | | | | | | | | | | | | | | | | | | | | Refactor the "do not stop feeding the backend early" logic into a small helper function and use it in both run_diff_files() and diff_tree() that has the stop-early optimization. We may later add other types of diffcore transformation that require to look at the whole result like diff-filter does, and having the logic in a single place is essential for longer term maintainability. Signed-off-by: Junio C Hamano <gitster@pobox.com>
| * diff_tree: disable QUICK optimization with diff filterJeff King2011-05-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We stop looking for changes early with QUICK, so our diff queue contains only a subset of the changes. However, we don't apply diff filters until later; it will appear at that point as though there are no changes matching our filter, when in reality we simply didn't keep looking for changes long enough. Commit 2cfe8a6 (diff --quiet: disable optimization when --diff-filter=X is used, 2011-03-16) fixes this in some cases by disabling the optimization when a filter is present. However, it only tweaked run_diff_files, missing the similar case in diff_tree. Thus the fix worked only for diffing the working tree and index, but not between trees. Noticed by Yasushi SHOJI. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Merge branch 'nd/struct-pathspec'Junio C Hamano2011-05-06
|\ \ | | | | | | | | | | | | | | | | | | | | | * nd/struct-pathspec: pathspec: rename per-item field has_wildcard to use_wildcard Improve tree_entry_interesting() handling code Convert read_tree{,_recursive} to support struct pathspec Reimplement read_tree_recursive() using tree_entry_interesting()
| * | Improve tree_entry_interesting() handling codeNguyễn Thái Ngọc Duy2011-03-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | t_e_i() can return -1 or 2 to early shortcut a search. Current code may use up to two variables to handle it. One for saving return value from t_e_i temporarily, one for saving return code 2. The second variable is not needed. If we make sure the first variable does not change until the next t_e_i() call, then we can do something like this: int ret = 0; while (...) { if (ret != 2) { ret = t_e_i(); if (ret < 0) /* no longer interesting */ break; if (ret == 0) /* skip this round */ continue; } /* ret > 0, interesting */ } Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | | Remove unused variablesJohannes Schindelin2011-03-22
|/ / | | | | | | | | | | | | Noticed by gcc 4.6.0. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | grep: drop pathspec_matches() in favor of tree_entry_interesting()Nguyễn Thái Ngọc Duy2011-02-03
| | | | | | | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | tree_entry_interesting(): support depth limitNguyễn Thái Ngọc Duy2011-02-03
| | | | | | | | | | | | | | | | | | | | | | | | This is needed to replace pathspec_matches() in builtin/grep.c. max_depth == -1 means infinite depth. Depth limit is only effective when pathspec.recursive == 1. When pathspec.recursive == 0, the behavior depends on match functions: non-recursive for tree_entry_interesting() and recursive for match_pathspec{,_depth} Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | diff-tree: convert base+baselen to writable strbufNguyễn Thái Ngọc Duy2011-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In traversing trees, a full path is splitted into two parts: base directory and entry. They are however quite often concatenated whenever a full path is needed. Current code allocates a new buffer, do two memcpy(), use it, then release. Instead this patch turns "base" to a writable, extendable buffer. When a concatenation is needed, the callee only needs to append "entry" to base, use it, then truncate the entry out again. "base" must remain unchanged before and after entering a function. This avoids quite a bit of malloc() and memcpy(). Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Move tree_entry_interesting() to tree-walk.c and export itNguyễn Thái Ngọc Duy2011-02-03
| | | | | | | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | tree_entry_interesting(): remove dependency on struct diff_optionsNguyễn Thái Ngọc Duy2011-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function can be potentially used in more places than just tree-diff.c. "struct diff_options" does not make much sense outside diff_tree_sha1(). While removing the use of diff_options, it also removes tree_entry_extract() call, which means S_ISDIR() uses the entry->mode directly, without being filtered by canon_mode() (called internally inside tree_entry_extract). The only use of the mode information in this function is to check the type of the entry by giving it to S_ISDIR() macro, and the result does not change with or without canon_mode(), so it is ok to bypass tree_entry_extract(). Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Convert struct diff_options to use struct pathspecNguyễn Thái Ngọc Duy2011-02-03
| | | | | | | | | | Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
* | Merge branch 'en/tree-walk-optim'Junio C Hamano2010-10-26
|\ \ | | | | | | | | | | | | | | | | | | | | | * en/tree-walk-optim: diff_tree(): Skip skip_uninteresting() when all remaining paths interesting tree_entry_interesting(): Make return value more specific tree-walk: Correct bitrotted comment about tree_entry() Document pre-condition for tree_entry_interesting