Merge branch 'fk/blame' into next

* fk/blame:
  Add git-blame, a tool for assigning blame.

2 files changed, 444 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 8473281e3d..d8f7d03ed4 100644
--- a/Makefile
+++ b/Makefile
@@ -165,7 +165,7 @@ PROGRAMS = \
 	git-upload-pack$X git-verify-pack$X git-write-tree$X \
 	git-update-ref$X git-symbolic-ref$X git-check-ref-format$X \
 	git-name-rev$X git-pack-redundant$X git-repo-config$X git-var$X \
-	git-describe$X git-merge-tree$X
+	git-describe$X git-merge-tree$X git-blame$X
 
 # what 'all' will build and 'install' will install, in gitexecdir
 ALL_PROGRAMS = $(PROGRAMS) $(SIMPLE_PROGRAMS) $(SCRIPTS)
diff --git a/blame.c b/blame.c
new file mode 100644
index 0000000000..1e655466a8
--- /dev/null
+++ b/blame.c
@@ -0,0 +1,443 @@
+#include <assert.h>
+
+#include "cache.h"
+#include "refs.h"
+#include "tag.h"
+#include "commit.h"
+#include "tree.h"
+#include "blob.h"
+#include "epoch.h"
+#include "diff.h"
+
+#define DEBUG 0
+
+struct commit** blame_lines;
+int num_blame_lines;
+
+struct util_info
+{
+    int* line_map;
+    int num_lines;
+    unsigned char sha1[20]; /* blob sha, not commit! */
+    char* buf;
+    unsigned long size;
+//    const char* path;
+};
+
+struct chunk
+{
+    int off1, len1; // ---
+    int off2, len2; // +++
+};
+
+struct patch
+{
+    struct chunk* chunks;
+    int num;
+};
+
+static void get_blob(struct commit* commit);
+
+int num_get_patch = 0;
+int num_commits = 0;
+
+struct patch* get_patch(struct commit* commit, struct commit* other)
+{
+    struct patch* ret = xmalloc(sizeof(struct patch));
+    ret->chunks = NULL;
+    ret->num = 0;
+
+    struct util_info* info_c = (struct util_info*) commit->object.util;
+    struct util_info* info_o = (struct util_info*) other->object.util;
+
+    if(!memcmp(info_c->sha1, info_o->sha1, 20))
+        return ret;
+
+    get_blob(commit);
+    get_blob(other);
+
+    FILE* fout = fopen("/tmp/git-blame-tmp1", "w");
+    if(!fout)
+        die("fopen tmp1 failed: %s", strerror(errno));
+
+    if(fwrite(info_c->buf, info_c->size, 1, fout) != 1)
+        die("fwrite 1 failed: %s", strerror(errno));
+    fclose(fout);
+
+    fout = fopen("/tmp/git-blame-tmp2", "w");
+    if(!fout)
+        die("fopen tmp2 failed: %s", strerror(errno));
+
+    if(fwrite(info_o->buf, info_o->size, 1, fout) != 1)
+        die("fwrite 2 failed: %s", strerror(errno));
+    fclose(fout);
+
+    FILE* fin = popen("diff -u0 /tmp/git-blame-tmp1 /tmp/git-blame-tmp2", "r");
+    if(!fin)
+        die("popen failed: %s", strerror(errno));
+
+    char buf[1024];
+    while(fgets(buf, sizeof(buf), fin)) {
+        if(buf[0] != '@' || buf[1] != '@')
+            continue;
+
+        if(DEBUG)
+            printf("chunk line: %s", buf);
+        ret->num++;
+        ret->chunks = xrealloc(ret->chunks, sizeof(struct chunk)*ret->num);
+        struct chunk* chunk = &ret->chunks[ret->num-1];
+
+        assert(!strncmp(buf, "@@ -", 4));
+
+        char* start = buf+4;
+        char* sp = index(start, ' ');
+        *sp = '\0';
+        if(index(start, ',')) {
+            int ret = sscanf(start, "%d,%d", &chunk->off1, &chunk->len1);
+            assert(ret == 2);
+        } else {
+            int ret = sscanf(start, "%d", &chunk->off1);
+            assert(ret == 1);
+            chunk->len1 = 1;
+        }
+        *sp = ' ';
+
+        start = sp+1;
+        sp = index(start, ' ');
+        *sp = '\0';
+        if(index(start, ',')) {
+            int ret = sscanf(start, "%d,%d", &chunk->off2, &chunk->len2);
+            assert(ret == 2);
+        } else {
+            int ret = sscanf(start, "%d", &chunk->off2);
+            assert(ret == 1);
+            chunk->len2 = 1;
+        }
+        *sp = ' ';
+
+        if(chunk->off1 > 0)
+            chunk->off1 -= 1;
+        if(chunk->off2 > 0)
+            chunk->off2 -= 1;
+
+        assert(chunk->off1 >= 0);
+        assert(chunk->off2 >= 0);
+    }
+    fclose(fin);
+
+    num_get_patch++;
+    return ret;
+}
+
+void free_patch(struct patch* p)
+{
+    free(p->chunks);
+    free(p);
+}
+
+static int get_blob_sha1_internal(unsigned char *sha1, const char *base, int baselen,
+                                  const char *pathname, unsigned mode, int stage);
+
+
+static unsigned char blob_sha1[20];
+static int get_blob_sha1(struct tree* t, const char* pathname, unsigned char* sha1)
+{
+    const char *pathspec[2];
+    pathspec[0] = pathname;
+    pathspec[1] = NULL;
+    memset(blob_sha1, 0, sizeof(blob_sha1));
+    read_tree_recursive(t, "", 0, 0, pathspec, get_blob_sha1_internal);
+
+    int i;
+    for(i = 0; i < 20; i++) {
+        if(blob_sha1[i] != 0)
+            break;
+    }
+
+    if(i == 20)
+        return -1;
+
+    memcpy(sha1, blob_sha1, 20);
+    return 0;
+}
+
+static int get_blob_sha1_internal(unsigned char *sha1, const char *base, int baselen,
+                                  const char *pathname, unsigned mode, int stage)
+{
+//    printf("Got blob: %s base: '%s' baselen: %d pathname: '%s' mode: %o stage: %d\n",
+//           sha1_to_hex(sha1), base, baselen, pathname, mode, stage);
+
+    if(S_ISDIR(mode))
+        return READ_TREE_RECURSIVE;
+
+    memcpy(blob_sha1, sha1, 20);
+    return -1;
+}
+
+static void get_blob(struct commit* commit)
+{
+    struct util_info* info = commit->object.util;
+    char type[20];
+
+    if(info->buf)
+        return;
+
+    info->buf = read_sha1_file(info->sha1, type, &info->size);
+    assert(!strcmp(type, "blob"));
+}
+
+void print_patch(struct patch* p)
+{
+    printf("Num chunks: %d\n", p->num);
+    int i;
+    for(i = 0; i < p->num; i++) {
+        printf("%d,%d %d,%d\n", p->chunks[i].off1, p->chunks[i].len1, p->chunks[i].off2, p->chunks[i].len2);
+    }
+}
+
+
+// p is a patch from commit to other.
+void fill_line_map(struct commit* commit, struct commit* other, struct patch* p)
+{
+    int num_lines = ((struct util_info*) commit->object.util)->num_lines;
+    int* line_map = ((struct util_info*) commit->object.util)->line_map;
+    int num_lines2 = ((struct util_info*) other->object.util)->num_lines;
+    int* line_map2 = ((struct util_info*) other->object.util)->line_map;
+    int cur_chunk = 0;
+    int i1, i2;
+
+    if(p->num && DEBUG)
+        print_patch(p);
+
+    for(i1 = 0; i1 < num_lines; i1++)
+        line_map[i1] = -1;
+
+    if(DEBUG)
+        printf("num lines 1: %d num lines 2: %d\n", num_lines, num_lines2);
+
+    for(i1 = 0, i2 = 0; i1 < num_lines; i1++, i2++) {
+        if(DEBUG > 1)
+            printf("%d %d\n", i1, i2);
+
+        if(i2 >= num_lines2)
+            break;
+
+        line_map[i1] = line_map2[i2];
+
+        struct chunk* chunk = NULL;
+        if(cur_chunk < p->num)
+            chunk = &p->chunks[cur_chunk];
+
+        if(chunk && chunk->off1 == i1) {
+            i2 = chunk->off2;
+
+            if(chunk->len1 > 0)
+                i1 += chunk->len1-1;
+            if(chunk->len2 > 0)
+                i2 += chunk->len2-1;
+            cur_chunk++;
+        }
+    }
+}
+
+int map_line(struct commit* commit, int line)
+{
+    struct util_info* info = commit->object.util;
+    assert(line >= 0 && line < info->num_lines);
+    return info->line_map[line];
+}
+
+int fill_util_info(struct commit* commit, const char* path)
+{
+    if(commit->object.util)
+        return 0;
+
+    struct util_info* util = xmalloc(sizeof(struct util_info));
+    util->buf = NULL;
+    util->size = 0;
+    util->num_lines = -1;
+    util->line_map = NULL;
+
+    commit->object.util = util;
+
+    if(get_blob_sha1(commit->tree, path, util->sha1))
+        return -1;
+
+    return 0;
+}
+
+void alloc_line_map(struct commit* commit)
+{
+    struct util_info* util = commit->object.util;
+
+    if(util->line_map)
+        return;
+
+    get_blob(commit);
+
+    int i;
+    util->num_lines = 0;
+    for(i = 0; i < util->size; i++) {
+        if(util->buf[i] == '\n')
+            util->num_lines++;
+    }
+    util->line_map = xmalloc(sizeof(int)*util->num_lines);
+}
+
+void copy_line_map(struct commit* dst, struct commit* src)
+{
+    struct util_info* u_dst = dst->object.util;
+    struct util_info* u_src = src->object.util;
+
+    u_dst->line_map = u_src->line_map;
+    u_dst->num_lines = u_src->num_lines;
+    u_dst->buf = u_src->buf;
+    u_dst->size = u_src->size;
+}
+
+void process_commits(struct commit_list* list, const char* path)
+{
+    int i;
+
+    while(list) {
+        struct commit* commit = pop_commit(&list);
+        struct commit_list* parents;
+        struct util_info* info;
+
+        info = commit->object.util;
+        num_commits++;
+        if(DEBUG)
+            printf("\nProcessing commit: %d %s\n", num_commits, sha1_to_hex(commit->object.sha1));
+        for(parents = commit->parents;
+            parents != NULL; parents = parents->next) {
+            struct commit* parent = parents->item;
+
+            if(parse_commit(parent) < 0)
+                die("parse_commit error");
+
+            if(DEBUG)
+                printf("parent: %s\n", sha1_to_hex(parent->object.sha1));
+
+            if(fill_util_info(parent, path))
+                continue;
+
+            // Temporarily assign everything to the parent.
+            int num_blame = 0;
+            for(i = 0; i < num_blame_lines; i++) {
+                if(blame_lines[i] == commit) {
+                    num_blame++;
+                    blame_lines[i] = parent;
+                }
+            }
+
+            if(num_blame == 0)
+                continue;
+
+            struct patch* patch = get_patch(parent, commit);
+            if(patch->num == 0) {
+                copy_line_map(parent, commit);
+            } else {
+                alloc_line_map(parent);
+                fill_line_map(parent, commit, patch);
+            }
+
+            for(i = 0; i < patch->num; i++) {
+                int l;
+                for(l = 0; l < patch->chunks[i].len2; l++) {
+                    int mapped_line = map_line(commit, patch->chunks[i].off2 + l);
+                    if(mapped_line != -1 && blame_lines[mapped_line] == parent)
+                        blame_lines[mapped_line] = commit;
+                }
+            }
+            free_patch(patch);
+        }
+    }
+}
+
+#define SEEN 1
+struct commit_list* get_commit_list(struct commit* commit, const char* pathname)
+{
+    struct commit_list* ret = NULL;
+    struct commit_list* process = NULL;
+    unsigned char sha1[20];
+
+    commit_list_insert(commit, &process);
+
+    while(process) {
+        struct commit* com = pop_commit(&process);
+        if(com->object.flags & SEEN)
+            continue;
+
+        com->object.flags |= SEEN;
+        commit_list_insert(com, &ret);
+        struct commit_list* parents;
+
+        parse_commit(com);
+
+        for(parents = com->parents;
+            parents != NULL; parents = parents->next) {
+            struct commit* parent = parents->item;
+
+            parse_commit(parent);
+
+            if(!get_blob_sha1(parent->tree, pathname, sha1))
+                commit_list_insert(parent, &process);
+        }
+    }
+
+    return ret;
+}
+
+int main(int argc, const char **argv)
+{
+    unsigned char sha1[20];
+    struct commit *commit;
+    const char* filename;
+    int i;
+
+    setup_git_directory();
+
+    if (argc != 3)
+        die("Usage: blame commit-ish file");
+
+    if (get_sha1(argv[1], sha1))
+        die("get_sha1 failed");
+
+    commit = lookup_commit_reference(sha1);
+
+    filename = argv[2];
+
+    struct commit_list* list = get_commit_list(commit, filename);
+    sort_in_topological_order(&list, 1);
+
+    if(fill_util_info(commit, filename)) {
+        printf("%s not found in %s\n", filename, argv[1]);
+        return 0;
+    }
+    alloc_line_map(commit);
+
+    struct util_info* util = commit->object.util;
+    num_blame_lines = util->num_lines;
+    blame_lines = xmalloc(sizeof(struct commit*)*num_blame_lines);
+
+
+    for(i = 0; i < num_blame_lines; i++) {
+        blame_lines[i] = commit;
+
+        ((struct util_info*) commit->object.util)->line_map[i] = i;
+    }
+
+    process_commits(list, filename);
+
+    for(i = 0; i < num_blame_lines; i++) {
+        printf("%d %s\n", i+1-1, sha1_to_hex(blame_lines[i]->object.sha1));
+//        printf("%d %s\n", i+1-1, find_unique_abbrev(blame_lines[i]->object.sha1, 6));
+    }
+
+    if(DEBUG) {
+        printf("num get patch: %d\n", num_get_patch);
+        printf("num commits: %d\n", num_commits);
+    }
+
+    return 0;
+}