From a9ed376b158faf82d3685b51d546ccaeda716da3 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 28 Jun 2006 21:57:12 -0700 Subject: [PATCH 1/3] xdiff: generate "anti-diffs" aka what is common to two files This fairly trivial patch adds a new XDL_EMIT_xxx flag to tell libxdiff that we don't want to generate the _diff_ between two files, we want to see the lines that are _common_ to two files. So when you set XDL_EMIT_COMMON, xdl_diff() will do everything exactly like it used to do, but the output records it generates just contain the lines that aren't part of the diff. This is for doing things like generating the common base case for a file that was added in both branches. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano --- xdiff/xdiff.h | 1 + xdiff/xemit.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h index 2ce10b4c0d..c9f817818a 100644 --- a/xdiff/xdiff.h +++ b/xdiff/xdiff.h @@ -39,6 +39,7 @@ extern "C" { #define XDL_PATCH_IGNOREBSPACE (1 << 8) #define XDL_EMIT_FUNCNAMES (1 << 0) +#define XDL_EMIT_COMMON (1 << 1) #define XDL_MMB_READONLY (1 << 0) diff --git a/xdiff/xemit.c b/xdiff/xemit.c index ad5bfb1910..714c563547 100644 --- a/xdiff/xemit.c +++ b/xdiff/xemit.c @@ -100,6 +100,21 @@ static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) { } +int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, + xdemitconf_t const *xecfg) { + xdfile_t *xdf = &xe->xdf1; + const char *rchg = xdf->rchg; + long ix; + + for (ix = 0; ix < xdf->nrec; ix++) { + if (rchg[ix]) + continue; + if (xdl_emit_record(xdf, ix, "", ecb)) + return -1; + } + return 0; +} + int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, xdemitconf_t const *xecfg) { long s1, s2, e1, e2, lctx; @@ -107,6 +122,9 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, char funcbuf[40]; long funclen = 0; + if (xecfg->flags & XDL_EMIT_COMMON) + return xdl_emit_common(xe, xscr, ecb, xecfg); + for (xch = xche = xscr; xch; xch = xche->next) { xche = xdl_get_hunk(xch, xecfg); From 83788070a3dd0a4905dd76c865320c51f7d74a83 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 28 Jun 2006 11:18:27 -0700 Subject: [PATCH 2/3] Prepare "git-merge-tree" for future work This changes how "git-merge-tree" works in two ways: - instead of printing things out as we walk the trees, we save the results in memory. - when we've walked the tree fully, we print out the results in a more explicit way, describing the data. This is basically preparatory work for extending the git-merge-tree functionality in interesting directions. In particular, git-merge-tree is also how you would create a diff between two trees _without_ necessarily creating the merge commit itself. In other words, if you were to just wonder what another branch adds, you should be able to (eventually) just do git merge-tree -p $base HEAD $otherbranch to generate a diff of what the merge would look like. The current merge tree already basically has all the smarts for this, and the explanation of the results just means that hopefully somebody else than me could do the boring work. (You'd basically be able to do the above diff by just changing the printout format for the explanation, and making the "changed in both" first do a three-way merge before it diffs the result). The other thing that the in-memory format allows is rename detection (which the current code does not do). That's the basic reason why we don't want to just explain the differences as we go along - because we want to be able to look at the _other_ differences to see whether the reason an entry got deleted in either branch was perhaps because it got added in another place.. Rename detection should be a fairly trivial pass in between the tree diffing and the explanation. In the meantime, this doesn't actually do anything new, it just outputs the information in a more verbose manner. For an example merge, commit 5ab2c0a47574c92f92ea3709b23ca35d96319edd in the git tree works well and shows renames, along with true removals and additions and files that got changed in both branches. To see that as a tree merge, do: git-merge-tree 64e86c57 c5c23745 928e47e3 where the two last ones are the tips that got merged, and the first one is the merge base. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano --- merge-tree.c | 134 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 119 insertions(+), 15 deletions(-) diff --git a/merge-tree.c b/merge-tree.c index 9dcaab7a85..fd0c2111c4 100644 --- a/merge-tree.c +++ b/merge-tree.c @@ -1,11 +1,79 @@ #include "cache.h" #include "tree-walk.h" +#include "blob.h" static const char merge_tree_usage[] = "git-merge-tree "; static int resolve_directories = 1; +struct merge_list { + struct merge_list *next; + struct merge_list *link; /* other stages for this object */ + + unsigned int stage : 2, + flags : 30; + unsigned int mode; + const char *path; + struct blob *blob; +}; + +static struct merge_list *merge_result, **merge_result_end = &merge_result; + +static void add_merge_entry(struct merge_list *entry) +{ + *merge_result_end = entry; + merge_result_end = &entry->next; +} + static void merge_trees(struct tree_desc t[3], const char *base); +static const char *explanation(struct merge_list *entry) +{ + switch (entry->stage) { + case 0: + return "merged"; + case 3: + return "added in remote"; + case 2: + if (entry->link) + return "added in both"; + return "added in local"; + } + + /* Existed in base */ + entry = entry->link; + if (!entry) + return "removed in both"; + + if (entry->link) + return "changed in both"; + + if (entry->stage == 3) + return "removed in local"; + return "removed in remote"; +} + +static void show_result_list(struct merge_list *entry) +{ + printf("%s\n", explanation(entry)); + do { + struct merge_list *link = entry->link; + static const char *desc[4] = { "result", "base", "our", "their" }; + printf(" %-6s %o %s %s\n", desc[entry->stage], entry->mode, sha1_to_hex(entry->blob->object.sha1), entry->path); + entry = link; + } while (entry); +} + +static void show_result(void) +{ + struct merge_list *walk; + + walk = merge_result; + while (walk) { + show_result_list(walk); + walk = walk->next; + } +} + /* An empty entry never compares same, not even to another empty entry */ static int same_entry(struct name_entry *a, struct name_entry *b) { @@ -15,24 +83,34 @@ static int same_entry(struct name_entry *a, struct name_entry *b) a->mode == b->mode; } -static const char *sha1_to_hex_zero(const unsigned char *sha1) +static struct merge_list *create_entry(unsigned stage, unsigned mode, const unsigned char *sha1, const char *path) { - if (sha1) - return sha1_to_hex(sha1); - return "0000000000000000000000000000000000000000"; + struct merge_list *res = xmalloc(sizeof(*res)); + + memset(res, 0, sizeof(*res)); + res->stage = stage; + res->path = path; + res->mode = mode; + res->blob = lookup_blob(sha1); + return res; } static void resolve(const char *base, struct name_entry *branch1, struct name_entry *result) { + struct merge_list *orig, *final; + const char *path; + /* If it's already branch1, don't bother showing it */ if (!branch1) return; - printf("0 %06o->%06o %s->%s %s%s\n", - branch1->mode, result->mode, - sha1_to_hex_zero(branch1->sha1), - sha1_to_hex_zero(result->sha1), - base, result->path); + path = strdup(mkpath("%s%s", base, result->path)); + orig = create_entry(2, branch1->mode, branch1->sha1, path); + final = create_entry(0, result->mode, result->sha1, path); + + final->link = orig; + + add_merge_entry(final); } static int unresolved_directory(const char *base, struct name_entry n[3]) @@ -71,16 +149,40 @@ static int unresolved_directory(const char *base, struct name_entry n[3]) return 1; } + +static struct merge_list *link_entry(unsigned stage, const char *base, struct name_entry *n, struct merge_list *entry) +{ + const char *path; + struct merge_list *link; + + if (!n->mode) + return entry; + if (entry) + path = entry->path; + else + path = strdup(mkpath("%s%s", base, n->path)); + link = create_entry(stage, n->mode, n->sha1, path); + link->link = entry; + return link; +} + static void unresolved(const char *base, struct name_entry n[3]) { + struct merge_list *entry = NULL; + if (unresolved_directory(base, n)) return; - if (n[0].sha1) - printf("1 %06o %s %s%s\n", n[0].mode, sha1_to_hex(n[0].sha1), base, n[0].path); - if (n[1].sha1) - printf("2 %06o %s %s%s\n", n[1].mode, sha1_to_hex(n[1].sha1), base, n[1].path); - if (n[2].sha1) - printf("3 %06o %s %s%s\n", n[2].mode, sha1_to_hex(n[2].sha1), base, n[2].path); + + /* + * Do them in reverse order so that the resulting link + * list has the stages in order - link_entry adds new + * links at the front. + */ + entry = link_entry(3, base, n + 2, entry); + entry = link_entry(2, base, n + 1, entry); + entry = link_entry(1, base, n + 0, entry); + + add_merge_entry(entry); } /* @@ -172,5 +274,7 @@ int main(int argc, char **argv) free(buf1); free(buf2); free(buf3); + + show_result(); return 0; } From 0c7993839b92f466278439a724023f8be50391c1 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 28 Jun 2006 22:06:36 -0700 Subject: [PATCH 3/3] Improved three-way blob merging code This fleshes out the code that generates a three-way merge of a set of blobs. It still actually does the three-way merge using an external executable (ie just calling "merge"), but the interfaces have been cleaned up a lot and are now fully based on the 'mmfile_t' interface, so if libxdiff were to ever grow a compatible three-way-merge, it could probably be directly plugged in. It also uses the previous XDL_EMIT_COMMON functionality extension to libxdiff to generate a made-up base file for the merge for the case where no base file previously existed. This should be equivalent to what we currently do in git-merge-one-file.sh: diff -u -La/$orig -Lb/$orig $orig $src2 | git-apply --no-add except it should be much simpler and can be done using the direct libxdiff interfaces. Signed-off-by: Linus Torvalds Signed-off-by: Junio C Hamano --- Makefile | 2 +- merge-file.c | 166 +++++++++++++++++++++++++++++++++++++++++++++++++++ merge-tree.c | 73 ++++++++++++++++++++++ 3 files changed, 240 insertions(+), 1 deletion(-) create mode 100644 merge-file.c diff --git a/Makefile b/Makefile index cde619c498..e880457526 100644 --- a/Makefile +++ b/Makefile @@ -217,7 +217,7 @@ LIB_OBJS = \ server-info.o setup.o sha1_file.o sha1_name.o strbuf.o \ tag.o tree.o usage.o config.o environment.o ctype.o copy.o \ fetch-clone.o revision.o pager.o tree-walk.o xdiff-interface.o \ - alloc.o $(DIFF_OBJS) + alloc.o merge-file.o $(DIFF_OBJS) BUILTIN_OBJS = \ builtin-log.o builtin-help.o builtin-count.o builtin-diff.o builtin-push.o \ diff --git a/merge-file.c b/merge-file.c new file mode 100644 index 0000000000..f32c653825 --- /dev/null +++ b/merge-file.c @@ -0,0 +1,166 @@ +#include "cache.h" +#include "run-command.h" +#include "xdiff-interface.h" +#include "blob.h" + +static void rm_temp_file(const char *filename) +{ + unlink(filename); + free((void *)filename); +} + +static const char *write_temp_file(mmfile_t *f) +{ + int fd; + const char *tmp = getenv("TMPDIR"); + char *filename; + + if (!tmp) + tmp = "/tmp"; + filename = mkpath("%s/%s", tmp, "git-tmp-XXXXXX"); + fd = mkstemp(filename); + if (fd < 0) + return NULL; + filename = strdup(filename); + if (f->size != xwrite(fd, f->ptr, f->size)) { + rm_temp_file(filename); + return NULL; + } + close(fd); + return filename; +} + +static void *read_temp_file(const char *filename, unsigned long *size) +{ + struct stat st; + char *buf = NULL; + int fd = open(filename, O_RDONLY); + if (fd < 0) + return NULL; + if (!fstat(fd, &st)) { + *size = st.st_size; + buf = xmalloc(st.st_size); + if (st.st_size != xread(fd, buf, st.st_size)) { + free(buf); + buf = NULL; + } + } + close(fd); + return buf; +} + +static int fill_mmfile_blob(mmfile_t *f, struct blob *obj) +{ + void *buf; + unsigned long size; + char type[20]; + + buf = read_sha1_file(obj->object.sha1, type, &size); + if (!buf) + return -1; + if (strcmp(type, blob_type)) + return -1; + f->ptr = buf; + f->size = size; + return 0; +} + +static void free_mmfile(mmfile_t *f) +{ + free(f->ptr); +} + +static void *three_way_filemerge(mmfile_t *base, mmfile_t *our, mmfile_t *their, unsigned long *size) +{ + void *res; + const char *t1, *t2, *t3; + + t1 = write_temp_file(base); + t2 = write_temp_file(our); + t3 = write_temp_file(their); + res = NULL; + if (t1 && t2 && t3) { + int code = run_command("merge", t2, t1, t3, NULL); + if (!code || code == -1) + res = read_temp_file(t2, size); + } + rm_temp_file(t1); + rm_temp_file(t2); + rm_temp_file(t3); + return res; +} + +static int common_outf(void *priv_, mmbuffer_t *mb, int nbuf) +{ + int i; + mmfile_t *dst = priv_; + + for (i = 0; i < nbuf; i++) { + memcpy(dst->ptr + dst->size, mb[i].ptr, mb[i].size); + dst->size += mb[i].size; + } + return 0; +} + +static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2) +{ + unsigned long size = f1->size < f2->size ? f1->size : f2->size; + void *ptr = xmalloc(size); + xpparam_t xpp; + xdemitconf_t xecfg; + xdemitcb_t ecb; + + xpp.flags = XDF_NEED_MINIMAL; + xecfg.ctxlen = 3; + xecfg.flags = XDL_EMIT_COMMON; + ecb.outf = common_outf; + + res->ptr = ptr; + res->size = 0; + + ecb.priv = res; + return xdl_diff(f1, f2, &xpp, &xecfg, &ecb); +} + +void *merge_file(struct blob *base, struct blob *our, struct blob *their, unsigned long *size) +{ + void *res = NULL; + mmfile_t f1, f2, common; + + /* + * Removed in either branch? + * + * NOTE! This depends on the caller having done the + * proper warning about removing a file that got + * modified in the other branch! + */ + if (!our || !their) { + char type[20]; + if (base) + return NULL; + if (!our) + our = their; + return read_sha1_file(our->object.sha1, type, size); + } + + if (fill_mmfile_blob(&f1, our) < 0) + goto out_no_mmfile; + if (fill_mmfile_blob(&f2, their) < 0) + goto out_free_f1; + + if (base) { + if (fill_mmfile_blob(&common, base) < 0) + goto out_free_f2_f1; + } else { + if (generate_common_file(&common, &f1, &f2) < 0) + goto out_free_f2_f1; + } + res = three_way_filemerge(&common, &f1, &f2, size); + free_mmfile(&common); +out_free_f2_f1: + free_mmfile(&f2); +out_free_f1: + free_mmfile(&f1); +out_no_mmfile: + return res; +} diff --git a/merge-tree.c b/merge-tree.c index fd0c2111c4..7cf00be6d5 100644 --- a/merge-tree.c +++ b/merge-tree.c @@ -1,5 +1,6 @@ #include "cache.h" #include "tree-walk.h" +#include "xdiff-interface.h" #include "blob.h" static const char merge_tree_usage[] = "git-merge-tree "; @@ -52,6 +53,77 @@ static const char *explanation(struct merge_list *entry) return "removed in remote"; } +extern void *merge_file(struct blob *, struct blob *, struct blob *, unsigned long *); + +static void *result(struct merge_list *entry, unsigned long *size) +{ + char type[20]; + struct blob *base, *our, *their; + + if (!entry->stage) + return read_sha1_file(entry->blob->object.sha1, type, size); + base = NULL; + if (entry->stage == 1) { + base = entry->blob; + entry = entry->link; + } + our = NULL; + if (entry && entry->stage == 2) { + our = entry->blob; + entry = entry->link; + } + their = NULL; + if (entry) + their = entry->blob; + return merge_file(base, our, their, size); +} + +static void *origin(struct merge_list *entry, unsigned long *size) +{ + char type[20]; + while (entry) { + if (entry->stage == 2) + return read_sha1_file(entry->blob->object.sha1, type, size); + entry = entry->link; + } + return NULL; +} + +static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf) +{ + int i; + for (i = 0; i < nbuf; i++) + printf("%.*s", (int) mb[i].size, mb[i].ptr); + return 0; +} + +static void show_diff(struct merge_list *entry) +{ + unsigned long size; + mmfile_t src, dst; + xpparam_t xpp; + xdemitconf_t xecfg; + xdemitcb_t ecb; + + xpp.flags = XDF_NEED_MINIMAL; + xecfg.ctxlen = 3; + xecfg.flags = 0; + ecb.outf = show_outf; + ecb.priv = NULL; + + src.ptr = origin(entry, &size); + if (!src.ptr) + size = 0; + src.size = size; + dst.ptr = result(entry, &size); + if (!dst.ptr) + size = 0; + dst.size = size; + xdl_diff(&src, &dst, &xpp, &xecfg, &ecb); + free(src.ptr); + free(dst.ptr); +} + static void show_result_list(struct merge_list *entry) { printf("%s\n", explanation(entry)); @@ -70,6 +142,7 @@ static void show_result(void) walk = merge_result; while (walk) { show_result_list(walk); + show_diff(walk); walk = walk->next; } }