--- /dev/null
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "blame_git.h"
+
+#include "commit.h"
+#include "blob.h"
+#include "xdiff/xinclude.h"
+#include "diff_xdiff.h"
+
+/*
+ * Origin is refcounted and usually we keep the blob contents to be
+ * reused.
+ */
+static git_blame__origin *origin_incref(git_blame__origin *o)
+{
+ if (o)
+ o->refcnt++;
+ return o;
+}
+
+static void origin_decref(git_blame__origin *o)
+{
+ if (o && --o->refcnt <= 0) {
+ if (o->previous)
+ origin_decref(o->previous);
+ git_blob_free(o->blob);
+ git_commit_free(o->commit);
+ git__free(o);
+ }
+}
+
+/* Given a commit and a path in it, create a new origin structure. */
+static int make_origin(git_blame__origin **out, git_commit *commit, const char *path)
+{
+ git_blame__origin *o;
+ git_object *blob;
+ size_t path_len = strlen(path), alloc_len;
+ int error = 0;
+
+ if ((error = git_object_lookup_bypath(&blob, (git_object*)commit,
+ path, GIT_OBJECT_BLOB)) < 0)
+ return error;
+
+ GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, sizeof(*o), path_len);
+ GIT_ERROR_CHECK_ALLOC_ADD(&alloc_len, alloc_len, 1);
+ o = git__calloc(1, alloc_len);
+ GIT_ERROR_CHECK_ALLOC(o);
+
+ o->commit = commit;
+ o->blob = (git_blob *) blob;
+ o->refcnt = 1;
+ strcpy(o->path, path);
+
+ *out = o;
+
+ return 0;
+}
+
+/* Locate an existing origin or create a new one. */
+int git_blame__get_origin(
+ git_blame__origin **out,
+ git_blame *blame,
+ git_commit *commit,
+ const char *path)
+{
+ git_blame__entry *e;
+
+ for (e = blame->ent; e; e = e->next) {
+ if (e->suspect->commit == commit && !strcmp(e->suspect->path, path)) {
+ *out = origin_incref(e->suspect);
+ }
+ }
+ return make_origin(out, commit, path);
+}
+
+typedef struct blame_chunk_cb_data {
+ git_blame *blame;
+ git_blame__origin *target;
+ git_blame__origin *parent;
+ long tlno;
+ long plno;
+}blame_chunk_cb_data;
+
+static bool same_suspect(git_blame__origin *a, git_blame__origin *b)
+{
+ if (a == b)
+ return true;
+ if (git_oid_cmp(git_commit_id(a->commit), git_commit_id(b->commit)))
+ return false;
+ return 0 == strcmp(a->path, b->path);
+}
+
+/* find the line number of the last line the target is suspected for */
+static bool find_last_in_target(size_t *out, git_blame *blame, git_blame__origin *target)
+{
+ git_blame__entry *e;
+ size_t last_in_target = 0;
+ bool found = false;
+
+ *out = 0;
+
+ for (e=blame->ent; e; e=e->next) {
+ if (e->guilty || !same_suspect(e->suspect, target))
+ continue;
+ if (last_in_target < e->s_lno + e->num_lines) {
+ found = true;
+ last_in_target = e->s_lno + e->num_lines;
+ }
+ }
+
+ *out = last_in_target;
+ return found;
+}
+
+/*
+ * It is known that lines between tlno to same came from parent, and e
+ * has an overlap with that range. it also is known that parent's
+ * line plno corresponds to e's line tlno.
+ *
+ * <---- e ----->
+ * <------> (entirely within)
+ * <------------> (extends past)
+ * <------------> (starts before)
+ * <------------------> (entirely encloses)
+ *
+ * Split e into potentially three parts; before this chunk, the chunk
+ * to be blamed for the parent, and after that portion.
+ */
+static void split_overlap(git_blame__entry *split, git_blame__entry *e,
+ size_t tlno, size_t plno, size_t same, git_blame__origin *parent)
+{
+ size_t chunk_end_lno;
+
+ if (e->s_lno < tlno) {
+ /* there is a pre-chunk part not blamed on the parent */
+ split[0].suspect = origin_incref(e->suspect);
+ split[0].lno = e->lno;
+ split[0].s_lno = e->s_lno;
+ split[0].num_lines = tlno - e->s_lno;
+ split[1].lno = e->lno + tlno - e->s_lno;
+ split[1].s_lno = plno;
+ } else {
+ split[1].lno = e->lno;
+ split[1].s_lno = plno + (e->s_lno - tlno);
+ }
+
+ if (same < e->s_lno + e->num_lines) {
+ /* there is a post-chunk part not blamed on parent */
+ split[2].suspect = origin_incref(e->suspect);
+ split[2].lno = e->lno + (same - e->s_lno);
+ split[2].s_lno = e->s_lno + (same - e->s_lno);
+ split[2].num_lines = e->s_lno + e->num_lines - same;
+ chunk_end_lno = split[2].lno;
+ } else {
+ chunk_end_lno = e->lno + e->num_lines;
+ }
+ split[1].num_lines = chunk_end_lno - split[1].lno;
+
+ /*
+ * if it turns out there is nothing to blame the parent for, forget about
+ * the splitting. !split[1].suspect signals this.
+ */
+ if (split[1].num_lines < 1)
+ return;
+ split[1].suspect = origin_incref(parent);
+}
+
+/*
+ * Link in a new blame entry to the scoreboard. Entries that cover the same
+ * line range have been removed from the scoreboard previously.
+ */
+static void add_blame_entry(git_blame *blame, git_blame__entry *e)
+{
+ git_blame__entry *ent, *prev = NULL;
+
+ origin_incref(e->suspect);
+
+ for (ent = blame->ent; ent && ent->lno < e->lno; ent = ent->next)
+ prev = ent;
+
+ /* prev, if not NULL, is the last one that is below e */
+ e->prev = prev;
+ if (prev) {
+ e->next = prev->next;
+ prev->next = e;
+ } else {
+ e->next = blame->ent;
+ blame->ent = e;
+ }
+ if (e->next)
+ e->next->prev = e;
+}
+
+/*
+ * src typically is on-stack; we want to copy the information in it to
+ * a malloced blame_entry that is already on the linked list of the scoreboard.
+ * The origin of dst loses a refcnt while the origin of src gains one.
+ */
+static void dup_entry(git_blame__entry *dst, git_blame__entry *src)
+{
+ git_blame__entry *p, *n;
+
+ p = dst->prev;
+ n = dst->next;
+ origin_incref(src->suspect);
+ origin_decref(dst->suspect);
+ memcpy(dst, src, sizeof(*src));
+ dst->prev = p;
+ dst->next = n;
+ dst->score = 0;
+}
+
+/*
+ * split_overlap() divided an existing blame e into up to three parts in split.
+ * Adjust the linked list of blames in the scoreboard to reflect the split.
+ */
+static int split_blame(git_blame *blame, git_blame__entry *split, git_blame__entry *e)
+{
+ git_blame__entry *new_entry;
+
+ if (split[0].suspect && split[2].suspect) {
+ /* The first part (reuse storage for the existing entry e */
+ dup_entry(e, &split[0]);
+
+ /* The last part -- me */
+ new_entry = git__malloc(sizeof(*new_entry));
+ GIT_ERROR_CHECK_ALLOC(new_entry);
+ memcpy(new_entry, &(split[2]), sizeof(git_blame__entry));
+ add_blame_entry(blame, new_entry);
+
+ /* ... and the middle part -- parent */
+ new_entry = git__malloc(sizeof(*new_entry));
+ GIT_ERROR_CHECK_ALLOC(new_entry);
+ memcpy(new_entry, &(split[1]), sizeof(git_blame__entry));
+ add_blame_entry(blame, new_entry);
+ } else if (!split[0].suspect && !split[2].suspect) {
+ /*
+ * The parent covers the entire area; reuse storage for e and replace it
+ * with the parent
+ */
+ dup_entry(e, &split[1]);
+ } else if (split[0].suspect) {
+ /* me and then parent */
+ dup_entry(e, &split[0]);
+ new_entry = git__malloc(sizeof(*new_entry));
+ GIT_ERROR_CHECK_ALLOC(new_entry);
+ memcpy(new_entry, &(split[1]), sizeof(git_blame__entry));
+ add_blame_entry(blame, new_entry);
+ } else {
+ /* parent and then me */
+ dup_entry(e, &split[1]);
+ new_entry = git__malloc(sizeof(*new_entry));
+ GIT_ERROR_CHECK_ALLOC(new_entry);
+ memcpy(new_entry, &(split[2]), sizeof(git_blame__entry));
+ add_blame_entry(blame, new_entry);
+ }
+
+ return 0;
+}
+
+/*
+ * After splitting the blame, the origins used by the on-stack blame_entry
+ * should lose one refcnt each.
+ */
+static void decref_split(git_blame__entry *split)
+{
+ int i;
+ for (i=0; i<3; i++)
+ origin_decref(split[i].suspect);
+}
+
+/*
+ * Helper for blame_chunk(). blame_entry e is known to overlap with the patch
+ * hunk; split it and pass blame to the parent.
+ */
+static int blame_overlap(
+ git_blame *blame,
+ git_blame__entry *e,
+ size_t tlno,
+ size_t plno,
+ size_t same,
+ git_blame__origin *parent)
+{
+ git_blame__entry split[3] = {{0}};
+
+ split_overlap(split, e, tlno, plno, same, parent);
+ if (split[1].suspect)
+ if (split_blame(blame, split, e) < 0)
+ return -1;
+ decref_split(split);
+
+ return 0;
+}
+
+/*
+ * Process one hunk from the patch between the current suspect for blame_entry
+ * e and its parent. Find and split the overlap, and pass blame to the
+ * overlapping part to the parent.
+ */
+static int blame_chunk(
+ git_blame *blame,
+ size_t tlno,
+ size_t plno,
+ size_t same,
+ git_blame__origin *target,
+ git_blame__origin *parent)
+{
+ git_blame__entry *e;
+
+ for (e = blame->ent; e; e = e->next) {
+ if (e->guilty || !same_suspect(e->suspect, target))
+ continue;
+ if (same <= e->s_lno)
+ continue;
+ if (tlno < e->s_lno + e->num_lines) {
+ if (blame_overlap(blame, e, tlno, plno, same, parent) < 0)
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int my_emit(
+ long start_a, long count_a,
+ long start_b, long count_b,
+ void *cb_data)
+{
+ blame_chunk_cb_data *d = (blame_chunk_cb_data *)cb_data;
+
+ if (blame_chunk(d->blame, d->tlno, d->plno, start_b, d->target, d->parent) < 0)
+ return -1;
+ d->plno = start_a + count_a;
+ d->tlno = start_b + count_b;
+
+ return 0;
+}
+
+static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
+{
+ const int blk = 1024;
+ long trimmed = 0, recovered = 0;
+ char *ap = a->ptr + a->size;
+ char *bp = b->ptr + b->size;
+ long smaller = (long)((a->size < b->size) ? a->size : b->size);
+
+ if (ctx)
+ return;
+
+ while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
+ trimmed += blk;
+ ap -= blk;
+ bp -= blk;
+ }
+
+ while (recovered < trimmed)
+ if (ap[recovered++] == '\n')
+ break;
+ a->size -= trimmed - recovered;
+ b->size -= trimmed - recovered;
+}
+
+static int diff_hunks(mmfile_t file_a, mmfile_t file_b, void *cb_data, git_blame_options *options)
+{
+ xdemitconf_t xecfg = {0};
+ xdemitcb_t ecb = {0};
+ xpparam_t xpp = {0};
+
+ if (options->flags & GIT_BLAME_IGNORE_WHITESPACE)
+ xpp.flags |= XDF_IGNORE_WHITESPACE;
+
+ xecfg.hunk_func = my_emit;
+ ecb.priv = cb_data;
+
+ trim_common_tail(&file_a, &file_b, 0);
+
+ if (file_a.size > GIT_XDIFF_MAX_SIZE ||
+ file_b.size > GIT_XDIFF_MAX_SIZE) {
+ git_error_set(GIT_ERROR_INVALID, "file too large to blame");
+ return -1;
+ }
+
+ return xdl_diff(&file_a, &file_b, &xpp, &xecfg, &ecb);
+}
+
+static void fill_origin_blob(git_blame__origin *o, mmfile_t *file)
+{
+ memset(file, 0, sizeof(*file));
+ if (o->blob) {
+ file->ptr = (char*)git_blob_rawcontent(o->blob);
+ file->size = (long)git_blob_rawsize(o->blob);
+ }
+}
+
+static int pass_blame_to_parent(
+ git_blame *blame,
+ git_blame__origin *target,
+ git_blame__origin *parent)
+{
+ size_t last_in_target;
+ mmfile_t file_p, file_o;
+ blame_chunk_cb_data d = { blame, target, parent, 0, 0 };
+
+ if (!find_last_in_target(&last_in_target, blame, target))
+ return 1; /* nothing remains for this target */
+
+ fill_origin_blob(parent, &file_p);
+ fill_origin_blob(target, &file_o);
+
+ if (diff_hunks(file_p, file_o, &d, &blame->options) < 0)
+ return -1;
+
+ /* The reset (i.e. anything after tlno) are the same as the parent */
+ if (blame_chunk(blame, d.tlno, d.plno, last_in_target, target, parent) < 0)
+ return -1;
+
+ return 0;
+}
+
+static int paths_on_dup(void **old, void *new)
+{
+ GIT_UNUSED(old);
+ git__free(new);
+ return -1;
+}
+
+static git_blame__origin *find_origin(
+ git_blame *blame,
+ git_commit *parent,
+ git_blame__origin *origin)
+{
+ git_blame__origin *porigin = NULL;
+ git_diff *difflist = NULL;
+ git_diff_options diffopts = GIT_DIFF_OPTIONS_INIT;
+ git_tree *otree=NULL, *ptree=NULL;
+
+ /* Get the trees from this commit and its parent */
+ if (0 != git_commit_tree(&otree, origin->commit) ||
+ 0 != git_commit_tree(&ptree, parent))
+ goto cleanup;
+
+ /* Configure the diff */
+ diffopts.context_lines = 0;
+ diffopts.flags = GIT_DIFF_SKIP_BINARY_CHECK;
+
+ /* Check to see if files we're interested have changed */
+ diffopts.pathspec.count = blame->paths.length;
+ diffopts.pathspec.strings = (char**)blame->paths.contents;
+ if (0 != git_diff_tree_to_tree(&difflist, blame->repository, ptree, otree, &diffopts))
+ goto cleanup;
+
+ if (!git_diff_num_deltas(difflist)) {
+ /* No changes; copy data */
+ git_blame__get_origin(&porigin, blame, parent, origin->path);
+ } else {
+ git_diff_find_options findopts = GIT_DIFF_FIND_OPTIONS_INIT;
+ int i;
+
+ /* Generate a full diff between the two trees */
+ git_diff_free(difflist);
+ diffopts.pathspec.count = 0;
+ if (0 != git_diff_tree_to_tree(&difflist, blame->repository, ptree, otree, &diffopts))
+ goto cleanup;
+
+ /* Let diff find renames */
+ findopts.flags = GIT_DIFF_FIND_RENAMES;
+ if (0 != git_diff_find_similar(difflist, &findopts))
+ goto cleanup;
+
+ /* Find one that matches */
+ for (i=0; i<(int)git_diff_num_deltas(difflist); i++) {
+ const git_diff_delta *delta = git_diff_get_delta(difflist, i);
+
+ if (!git_vector_bsearch(NULL, &blame->paths, delta->new_file.path))
+ {
+ git_vector_insert_sorted(&blame->paths, (void*)git__strdup(delta->old_file.path),
+ paths_on_dup);
+ make_origin(&porigin, parent, delta->old_file.path);
+ }
+ }
+ }
+
+cleanup:
+ git_diff_free(difflist);
+ git_tree_free(otree);
+ git_tree_free(ptree);
+ return porigin;
+}
+
+/*
+ * The blobs of origin and porigin exactly match, so everything origin is
+ * suspected for can be blamed on the parent.
+ */
+static int pass_whole_blame(git_blame *blame,
+ git_blame__origin *origin, git_blame__origin *porigin)
+{
+ git_blame__entry *e;
+
+ if (!porigin->blob &&
+ git_object_lookup((git_object**)&porigin->blob, blame->repository,
+ git_blob_id(origin->blob), GIT_OBJECT_BLOB) < 0)
+ return -1;
+ for (e=blame->ent; e; e=e->next) {
+ if (!same_suspect(e->suspect, origin))
+ continue;
+ origin_incref(porigin);
+ origin_decref(e->suspect);
+ e->suspect = porigin;
+ }
+
+ return 0;
+}
+
+static int pass_blame(git_blame *blame, git_blame__origin *origin, uint32_t opt)
+{
+ git_commit *commit = origin->commit;
+ int i, num_parents;
+ git_blame__origin *sg_buf[16];
+ git_blame__origin *porigin, **sg_origin = sg_buf;
+ int ret, error = 0;
+
+ num_parents = git_commit_parentcount(commit);
+ if (!git_oid_cmp(git_commit_id(commit), &blame->options.oldest_commit))
+ /* Stop at oldest specified commit */
+ num_parents = 0;
+ else if (opt & GIT_BLAME_FIRST_PARENT && num_parents > 1)
+ /* Limit search to the first parent */
+ num_parents = 1;
+
+ if (!num_parents) {
+ git_oid_cpy(&blame->options.oldest_commit, git_commit_id(commit));
+ goto finish;
+ } else if (num_parents < (int)ARRAY_SIZE(sg_buf))
+ memset(sg_buf, 0, sizeof(sg_buf));
+ else {
+ sg_origin = git__calloc(num_parents, sizeof(*sg_origin));
+ GIT_ERROR_CHECK_ALLOC(sg_origin);
+ }
+
+ for (i=0; i<num_parents; i++) {
+ git_commit *p;
+ int j, same;
+
+ if (sg_origin[i])
+ continue;
+
+ if ((error = git_commit_parent(&p, origin->commit, i)) < 0)
+ goto finish;
+ porigin = find_origin(blame, p, origin);
+
+ if (!porigin) {
+ /*
+ * We only have to decrement the parent's
+ * reference count when no porigin has
+ * been created, as otherwise the commit
+ * is assigned to the created object.
+ */
+ git_commit_free(p);
+ continue;
+ }
+ if (porigin->blob && origin->blob &&
+ !git_oid_cmp(git_blob_id(porigin->blob), git_blob_id(origin->blob))) {
+ error = pass_whole_blame(blame, origin, porigin);
+ origin_decref(porigin);
+ goto finish;
+ }
+ for (j = same = 0; j<i; j++)
+ if (sg_origin[j] &&
+ !git_oid_cmp(git_blob_id(sg_origin[j]->blob), git_blob_id(porigin->blob))) {
+ same = 1;
+ break;
+ }
+ if (!same)
+ sg_origin[i] = porigin;
+ else
+ origin_decref(porigin);
+ }
+
+ /* Standard blame */
+ for (i=0; i<num_parents; i++) {
+ git_blame__origin *porigin = sg_origin[i];
+ if (!porigin)
+ continue;
+ if (!origin->previous) {
+ origin_incref(porigin);
+ origin->previous = porigin;
+ }
+
+ if ((ret = pass_blame_to_parent(blame, origin, porigin)) != 0) {
+ if (ret < 0)
+ error = -1;
+
+ goto finish;
+ }
+ }
+
+ /* TODO: optionally find moves in parents' files */
+
+ /* TODO: optionally find copies in parents' files */
+
+finish:
+ for (i=0; i<num_parents; i++)
+ if (sg_origin[i])
+ origin_decref(sg_origin[i]);
+ if (sg_origin != sg_buf)
+ git__free(sg_origin);
+ return error;
+}
+
+/*
+ * If two blame entries that are next to each other came from
+ * contiguous lines in the same origin (i.e. <commit, path> pair),
+ * merge them together.
+ */
+static void coalesce(git_blame *blame)
+{
+ git_blame__entry *ent, *next;
+
+ for (ent=blame->ent; ent && (next = ent->next); ent = next) {
+ if (same_suspect(ent->suspect, next->suspect) &&
+ ent->guilty == next->guilty &&
+ ent->s_lno + ent->num_lines == next->s_lno)
+ {
+ ent->num_lines += next->num_lines;
+ ent->next = next->next;
+ if (ent->next)
+ ent->next->prev = ent;
+ origin_decref(next->suspect);
+ git__free(next);
+ ent->score = 0;
+ next = ent; /* again */
+ }
+ }
+}
+
+int git_blame__like_git(git_blame *blame, uint32_t opt)
+{
+ int error = 0;
+
+ while (true) {
+ git_blame__entry *ent;
+ git_blame__origin *suspect = NULL;
+
+ /* Find a suspect to break down */
+ for (ent = blame->ent; !suspect && ent; ent = ent->next)
+ if (!ent->guilty)
+ suspect = ent->suspect;
+ if (!suspect)
+ break;
+
+ /* We'll use this suspect later in the loop, so hold on to it for now. */
+ origin_incref(suspect);
+
+ if ((error = pass_blame(blame, suspect, opt)) < 0)
+ break;
+
+ /* Take responsibility for the remaining entries */
+ for (ent = blame->ent; ent; ent = ent->next) {
+ if (same_suspect(ent->suspect, suspect)) {
+ ent->guilty = true;
+ ent->is_boundary = !git_oid_cmp(
+ git_commit_id(suspect->commit),
+ &blame->options.oldest_commit);
+ }
+ }
+ origin_decref(suspect);
+ }
+
+ if (!error)
+ coalesce(blame);
+
+ return error;
+}
+
+void git_blame__free_entry(git_blame__entry *ent)
+{
+ if (!ent) return;
+ origin_decref(ent->suspect);
+ git__free(ent);
+}
projects / libgit2.git / blobdiff