ui-blame: add blame UI

Implement a page which provides the blame view of a specified file.

This feature is controlled by a new config variable, "enable-blame",
which is disabled by default.

Signed-off-by: Jeff Smith <whydoubt@gmail.com>
Reviewed-by: John Keeping <john@keeping.me.uk>

8 files changed, 265 insertions, 1 deletions

diff --git a/cgit.c b/cgit.c
index 1dae4b8..972a67e 100644
--- a/cgit.c
+++ b/cgit.c
@@ -167,6 +167,8 @@ static void config_cb(const char *name, const char *value)
                 ctx.cfg.enable_index_links = atoi(value);
         else if (!strcmp(name, "enable-index-owner"))
                 ctx.cfg.enable_index_owner = atoi(value);
+        else if (!strcmp(name, "enable-blame"))
+                ctx.cfg.enable_blame = atoi(value);
         else if (!strcmp(name, "enable-commit-graph"))
                 ctx.cfg.enable_commit_graph = atoi(value);
         else if (!strcmp(name, "enable-log-filecount"))
diff --git a/cgit.css b/cgit.css
index 1dc2c11..836f8ae 100644
--- a/cgit.css
+++ b/cgit.css
@@ -329,6 +329,14 @@ div#cgit table.ssdiff td.lineno a:hover {
         color: black;
 }
 
+div#cgit table.blame tr:nth-child(even) {
+        background: #eee;
+}
+
+div#cgit table.blame tr:nth-child(odd) {
+        background: white;
+}
+
 div#cgit table.bin-blob {
         margin-top: 0.5em;
         border: solid 1px black;
diff --git a/cgit.h b/cgit.h
index fbc6c6a..0b88dcd 100644
--- a/cgit.h
+++ b/cgit.h
@@ -228,6 +228,7 @@ struct cgit_config {
         int enable_http_clone;
         int enable_index_links;
         int enable_index_owner;
+        int enable_blame;
         int enable_commit_graph;
         int enable_log_filecount;
         int enable_log_linecount;
diff --git a/cgit.mk b/cgit.mk
index 90a2346..3fcc1ca 100644
--- a/cgit.mk
+++ b/cgit.mk
@@ -77,6 +77,7 @@ CGIT_OBJ_NAMES += parsing.o
 CGIT_OBJ_NAMES += scan-tree.o
 CGIT_OBJ_NAMES += shared.o
 CGIT_OBJ_NAMES += ui-atom.o
+CGIT_OBJ_NAMES += ui-blame.o
 CGIT_OBJ_NAMES += ui-blob.o
 CGIT_OBJ_NAMES += ui-clone.o
 CGIT_OBJ_NAMES += ui-commit.o
diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 9fcf445..4da166c 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -141,6 +141,11 @@ embedded::
         suitable for embedding in other html pages. Default value: none. See
         also: "noheader".
 
+enable-blame::
+        Flag which, when set to "1", will allow cgit to provide a "blame" page
+        for files, and will make it generate links to that page in appropriate
+        places. Default value: "0".
+
 enable-commit-graph::
         Flag which, when set to "1", will make cgit print an ASCII-art commit
         history graph to the left of the commit messages in the repository
@@ -799,6 +804,10 @@ enable-http-clone=1
 enable-index-links=1
 
 
+# Enable blame page and create links to it from tree page
+enable-blame=1
+
+
 # Enable ASCII art commit history graph on the log pages
 enable-commit-graph=1
 
diff --git a/cmd.c b/cmd.c
index d280e95..63f0ae5 100644
--- a/cmd.c
+++ b/cmd.c
@@ -1,6 +1,6 @@
 /* cmd.c: the cgit command dispatcher
  *
- * Copyright (C) 2006-2014 cgit Development Team <cgit@lists.zx2c4.com>
+ * Copyright (C) 2006-2017 cgit Development Team <cgit@lists.zx2c4.com>
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
@@ -11,6 +11,7 @@
 #include "cache.h"
 #include "ui-shared.h"
 #include "ui-atom.h"
+#include "ui-blame.h"
 #include "ui-blob.h"
 #include "ui-clone.h"
 #include "ui-commit.h"
@@ -63,6 +64,14 @@ static void about_fn(void)
                 cgit_print_site_readme();
 }
 
+static void blame_fn(void)
+{
+        if (ctx.cfg.enable_blame)
+                cgit_print_blame();
+        else
+                cgit_print_error_page(403, "Forbidden", "Blame is disabled");
+}
+
 static void blob_fn(void)
 {
         cgit_print_blob(ctx.qry.sha1, ctx.qry.path, ctx.qry.head, 0);
@@ -164,6 +173,7 @@ struct cgit_cmd *cgit_get_cmd(void)
                 def_cmd(HEAD, 1, 0, 1),
                 def_cmd(atom, 1, 0, 0),
                 def_cmd(about, 0, 0, 0),
+                def_cmd(blame, 1, 1, 0),
                 def_cmd(blob, 1, 0, 0),
                 def_cmd(commit, 1, 1, 0),
                 def_cmd(diff, 1, 1, 0),
diff --git a/ui-blame.c b/ui-blame.c
new file mode 100644
index 0000000..62cf431
--- /dev/null
+++ b/ui-blame.c
@@ -0,0 +1,227 @@
+/* ui-blame.c: functions for blame output
+ *
+ * Copyright (C) 2006-2017 cgit Development Team <cgit@lists.zx2c4.com>
+ *
+ * Licensed under GNU General Public License v2
+ *   (see COPYING for full license text)
+ */
+
+#include "cgit.h"
+#include "ui-blame.h"
+#include "html.h"
+#include "ui-shared.h"
+#include "argv-array.h"
+#include "blame.h"
+
+
+static char *emit_suspect_detail(struct blame_origin *suspect)
+{
+        struct commitinfo *info;
+        struct strbuf detail = STRBUF_INIT;
+
+        info = cgit_parse_commit(suspect->commit);
+
+        strbuf_addf(&detail, "author  %s", info->author);
+        if (!ctx.cfg.noplainemail)
+                strbuf_addf(&detail, " %s", info->author_email);
+        strbuf_addf(&detail, "  %s\n",
+                    show_date(info->author_date, info->author_tz,
+                                    cgit_date_mode(DATE_ISO8601)));
+
+        strbuf_addf(&detail, "committer  %s", info->committer);
+        if (!ctx.cfg.noplainemail)
+                strbuf_addf(&detail, " %s", info->committer_email);
+        strbuf_addf(&detail, "  %s\n\n",
+                    show_date(info->committer_date, info->committer_tz,
+                                    cgit_date_mode(DATE_ISO8601)));
+
+        strbuf_addstr(&detail, info->subject);
+
+        cgit_free_commitinfo(info);
+        return strbuf_detach(&detail, NULL);
+}
+
+static void emit_blame_entry(struct blame_scoreboard *sb,
+                             struct blame_entry *ent)
+{
+        struct blame_origin *suspect = ent->suspect;
+        struct object_id *oid = &suspect->commit->object.oid;
+        const char *numberfmt = "<a id='n%1$d' href='#n%1$d'>%1$d</a>\n";
+        const char *cp, *cpend;
+
+        char *detail = emit_suspect_detail(suspect);
+
+        html("<tr><td class='sha1 lines'>");
+        cgit_commit_link(find_unique_abbrev(oid->hash, DEFAULT_ABBREV), detail,
+                         NULL, ctx.qry.head, oid_to_hex(oid), suspect->path);
+        html("</td>\n");
+
+        free(detail);
+
+        if (ctx.cfg.enable_tree_linenumbers) {
+                unsigned long lineno = ent->lno;
+                html("<td class='linenumbers'><pre>");
+                while (lineno < ent->lno + ent->num_lines)
+                        htmlf(numberfmt, ++lineno);
+                html("</pre></td>\n");
+        }
+
+        cp = blame_nth_line(sb, ent->lno);
+        cpend = blame_nth_line(sb, ent->lno + ent->num_lines);
+
+        html("<td class='lines'><pre><code>");
+        html_ntxt(cp, cpend - cp);
+        html("</code></pre></td></tr>\n");
+}
+
+struct walk_tree_context {
+        char *curr_rev;
+        int match_baselen;
+        int state;
+};
+
+static void print_object(const unsigned char *sha1, const char *path,
+                         const char *basename, const char *rev)
+{
+        enum object_type type;
+        unsigned long size;
+        struct argv_array rev_argv = ARGV_ARRAY_INIT;
+        struct rev_info revs;
+        struct blame_scoreboard sb;
+        struct blame_origin *o;
+        struct blame_entry *ent = NULL;
+
+        type = sha1_object_info(sha1, &size);
+        if (type == OBJ_BAD) {
+                cgit_print_error_page(404, "Not found", "Bad object name: %s",
+                                      sha1_to_hex(sha1));
+                return;
+        }
+
+        argv_array_push(&rev_argv, "blame");
+        argv_array_push(&rev_argv, rev);
+        init_revisions(&revs, NULL);
+        DIFF_OPT_SET(&revs.diffopt, ALLOW_TEXTCONV);
+        setup_revisions(rev_argv.argc, rev_argv.argv, &revs, NULL);
+        init_scoreboard(&sb);
+        sb.revs = &revs;
+        setup_scoreboard(&sb, path, &o);
+        o->suspects = blame_entry_prepend(NULL, 0, sb.num_lines, o);
+        prio_queue_put(&sb.commits, o->commit);
+        blame_origin_decref(o);
+        sb.ent = NULL;
+        sb.path = path;
+        assign_blame(&sb, 0);
+        blame_sort_final(&sb);
+        blame_coalesce(&sb);
+
+        cgit_set_title_from_path(path);
+
+        cgit_print_layout_start();
+        htmlf("blob: %s (", sha1_to_hex(sha1));
+        cgit_plain_link("plain", NULL, NULL, ctx.qry.head, rev, path);
+        html(") (");
+        cgit_tree_link("tree", NULL, NULL, ctx.qry.head, rev, path);
+        html(")\n");
+
+        if (ctx.cfg.max_blob_size && size / 1024 > ctx.cfg.max_blob_size) {
+                htmlf("<div class='error'>blob size (%ldKB)"
+                      " exceeds display size limit (%dKB).</div>",
+                      size / 1024, ctx.cfg.max_blob_size);
+                return;
+        }
+
+        html("<table class='blame blob'>");
+        for (ent = sb.ent; ent; ) {
+                struct blame_entry *e = ent->next;
+                emit_blame_entry(&sb, ent);
+                free(ent);
+                ent = e;
+        }
+        html("</table>\n");
+        free((void *)sb.final_buf);
+
+        cgit_print_layout_end();
+}
+
+static int walk_tree(const unsigned char *sha1, struct strbuf *base,
+                     const char *pathname, unsigned mode, int stage,
+                     void *cbdata)
+{
+        struct walk_tree_context *walk_tree_ctx = cbdata;
+
+        if (base->len == walk_tree_ctx->match_baselen) {
+                if (S_ISREG(mode)) {
+                        struct strbuf buffer = STRBUF_INIT;
+                        strbuf_addbuf(&buffer, base);
+                        strbuf_addstr(&buffer, pathname);
+                        print_object(sha1, buffer.buf, pathname,
+                                     walk_tree_ctx->curr_rev);
+                        strbuf_release(&buffer);
+                        walk_tree_ctx->state = 1;
+                } else if (S_ISDIR(mode)) {
+                        walk_tree_ctx->state = 2;
+                }
+        } else if (base->len < INT_MAX
+                        && (int)base->len > walk_tree_ctx->match_baselen) {
+                walk_tree_ctx->state = 2;
+        } else if (S_ISDIR(mode)) {
+                return READ_TREE_RECURSIVE;
+        }
+        return 0;
+}
+
+static int basedir_len(const char *path)
+{
+        char *p = strrchr(path, '/');
+        if (p)
+                return p - path + 1;
+        return 0;
+}
+
+void cgit_print_blame(void)
+{
+        const char *rev = ctx.qry.sha1;
+        struct object_id oid;
+        struct commit *commit;
+        struct pathspec_item path_items = {
+                .match = ctx.qry.path,
+                .len = ctx.qry.path ? strlen(ctx.qry.path) : 0
+        };
+        struct pathspec paths = {
+                .nr = 1,
+                .items = &path_items
+        };
+        struct walk_tree_context walk_tree_ctx = {
+                .state = 0
+        };
+
+        if (!rev)
+                rev = ctx.qry.head;
+
+        if (get_oid(rev, &oid)) {
+                cgit_print_error_page(404, "Not found",
+                        "Invalid revision name: %s", rev);
+                return;
+        }
+        commit = lookup_commit_reference(&oid);
+        if (!commit || parse_commit(commit)) {
+                cgit_print_error_page(404, "Not found",
+                        "Invalid commit reference: %s", rev);
+                return;
+        }
+
+        walk_tree_ctx.curr_rev = xstrdup(rev);
+        walk_tree_ctx.match_baselen = (path_items.match) ?
+                                       basedir_len(path_items.match) : -1;
+
+        read_tree_recursive(commit->tree, "", 0, 0, &paths, walk_tree,
+                &walk_tree_ctx);
+        if (!walk_tree_ctx.state)
+                cgit_print_error_page(404, "Not found", "Not found");
+        else if (walk_tree_ctx.state == 2)
+                cgit_print_error_page(404, "No blame for folders",
+                        "Blame is not available for folders.");
+
+        free(walk_tree_ctx.curr_rev);
+}
diff --git a/ui-blame.h b/ui-blame.h
new file mode 100644
index 0000000..5b97e03
--- /dev/null
+++ b/ui-blame.h
@@ -0,0 +1,6 @@
+#ifndef UI_BLAME_H
+#define UI_BLAME_H
+
+extern void cgit_print_blame(void);
+
+#endif /* UI_BLAME_H */