Add graphical diffstat to commit view

The diffstat is calculated against the leftmost parent of the commit. This
gives nice information for "normal" merges while octopus merges are less
than optimal, so the diffstat isn't calculated for those merges.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

5 files changed, 130 insertions, 33 deletions

diff --git a/Makefile b/Makefile
index ccc7582..ea4d818 100644
--- a/Makefile
+++ b/Makefile
@@ -55,6 +55,7 @@ install: all clean-cache
         mkdir -p $(prefix)
         install cgit $(prefix)/cgit.cgi
         install cgit.css $(prefix)/cgit.css
+        install add.png del.png $(prefix)/
 
 clean-cgit:
         rm -f cgit *.o
diff --git a/add.png b/add.png
new file mode 100644
index 0000000..c550388
--- /dev/null
+++ b/add.png
diff --git a/cgit.css b/cgit.css
index cded981..b736b19 100644
--- a/cgit.css
+++ b/cgit.css
@@ -26,6 +26,13 @@ h3 {
         font-weight: normal;
 }
 
+h4 {
+        margin-top: 1.5em;
+        margin-bottom: 0.1em;
+        font-size: 100%;
+        font-weight: bold;
+}
+
 a {
         color: blue;
         text-decoration: none;
@@ -227,6 +234,12 @@ div.commit-msg {
 table.diffstat {
         border-collapse: collapse;
         margin-top: 1.5em;
+        width: 100%;
+        border: solid 1px #aaa;
+}
+
+table.diffstat tr:hover {
+        background-color: #eee;
 }
 
 table.diffstat th {
@@ -238,8 +251,11 @@ table.diffstat th {
 }
 
 table.diffstat td {
-        padding: 0.1em 1em 0.1em 0.1em;
+        padding: 0.2em 0.2em 0.1em 0.1em;
         font-size: 100%;
+        border: none;
+        border-top: solid 1px #aaa;
+        border-bottom: solid 1px #aaa;
 }
 
 table.diffstat td span.modechange {
@@ -259,7 +275,17 @@ table.diffstat td.upd a {
         color: blue;
 }
 
-table.diffstat td.summary {
+table.diffstat td.graph {
+        width: 75%;
+        vertical-align: center;
+}
+
+table.diffstat td.graph img {
+        border: none;
+        height: 11pt;
+}
+
+div.diffstat-summary {
         color: #888;
         padding-top: 0.5em;
 }
diff --git a/del.png b/del.png
new file mode 100644
index 0000000..5c73e82
--- /dev/null
+++ b/del.png
diff --git a/ui-commit.c b/ui-commit.c
index f1a22d3..ce33cf9 100644
--- a/ui-commit.c
+++ b/ui-commit.c
@@ -8,14 +8,30 @@
 
 #include "cgit.h"
 
-int files = 0;
+int files = 0, slots = 0;
+int total_adds = 0, total_rems = 0, max_changes = 0;
+int lines_added, lines_removed;
 
-void print_filepair(struct diff_filepair *pair)
+struct fileinfo {
+        char status;
+        unsigned char old_sha1[20];
+        unsigned char new_sha1[20];
+        unsigned short old_mode;
+        unsigned short new_mode;
+        char *old_path;
+        char *new_path;
+        unsigned int added;
+        unsigned int removed;
+} *items;
+
+
+void print_fileinfo(struct fileinfo *info)
 {
-        char *query;
+        char *query, *query2;
         char *class;
+        double width;
 
-        switch (pair->status) {
+        switch (info->status) {
         case DIFF_STATUS_ADDED:
                 class = "add";
                 break;
@@ -41,51 +57,98 @@ void print_filepair(struct diff_filepair *pair)
                 class = "stg";
                 break;
         default:
-                die("bug: unhandled diff status %c", pair->status);
+                die("bug: unhandled diff status %c", info->status);
         }
 
         html("<tr>");
         htmlf("<td class='mode'>");
-        if (is_null_sha1(pair->two->sha1)) {
-                html_filemode(pair->one->mode);
+        if (is_null_sha1(info->new_sha1)) {
+                html_filemode(info->old_mode);
         } else {
-                html_filemode(pair->two->mode);
+                html_filemode(info->new_mode);
         }
 
-        if (pair->one->mode != pair->two->mode &&
-            !is_null_sha1(pair->one->sha1) &&
-            !is_null_sha1(pair->two->sha1)) {
+        if (info->old_mode != info->new_mode &&
+            !is_null_sha1(info->old_sha1) &&
+            !is_null_sha1(info->new_sha1)) {
                 html("<span class='modechange'>[");
-                html_filemode(pair->one->mode);
+                html_filemode(info->old_mode);
                 html("]</span>");
         }
         htmlf("</td><td class='%s'>", class);
-        query = fmt("id=%s&id2=%s", sha1_to_hex(pair->one->sha1),
-                    sha1_to_hex(pair->two->sha1));
+        query = fmt("id=%s&id2=%s", sha1_to_hex(info->old_sha1),
+                    sha1_to_hex(info->new_sha1));
         html_link_open(cgit_pageurl(cgit_query_repo, "diff", query),
                        NULL, NULL);
-        if (pair->status == DIFF_STATUS_COPIED ||
-            pair->status == DIFF_STATUS_RENAMED) {
-                html_txt(pair->two->path);
-                htmlf("</a> (%s from ", pair->status == DIFF_STATUS_COPIED ?
+        if (info->status == DIFF_STATUS_COPIED ||
+            info->status == DIFF_STATUS_RENAMED) {
+                html_txt(info->new_path);
+                htmlf("</a> (%s from ", info->status == DIFF_STATUS_COPIED ?
                       "copied" : "renamed");
-                query = fmt("id=%s", sha1_to_hex(pair->one->sha1));
-                html_link_open(cgit_pageurl(cgit_query_repo, "view", query),
+                query2 = fmt("id=%s", sha1_to_hex(info->old_sha1));
+                html_link_open(cgit_pageurl(cgit_query_repo, "view", query2),
                                NULL, NULL);
-                html_txt(pair->one->path);
+                html_txt(info->old_path);
                 html("</a>)");
         } else {
-                html_txt(pair->two->path);
+                html_txt(info->new_path);
                 html("</a>");
         }
-        html("<td>");
+        html("</td><td class='right'>");
+        htmlf("%d", info->added + info->removed);
 
-        //TODO: diffstat graph
+        html("</td><td class='graph'>");
+        width = (info->added + info->removed) * 100.0 / max_changes;
+        if (width < 0.1)
+                width = 0.1;
+        html_link_open(cgit_pageurl(cgit_query_repo, "diff", query),
+                       NULL, NULL);
+        htmlf("<img src='/cgit/add.png' style='width: %.1f%%;'/>",
+              info->added * width / (info->added + info->removed));
+        htmlf("<img src='/cgit/del.png' style='width: %.1f%%;'/>",
+              info->removed * width / (info->added + info->removed));
+        html("</a></td></tr>\n");
+}
 
-        html("</td></tr>\n");
+void cgit_count_diff_lines(char *line, int len)
+{
+        if (line && (len > 0)) {
+                if (line[0] == '+')
+                        lines_added++;
+                else if (line[0] == '-')
+                        lines_removed++;
+        }
+}
+
+void inspect_filepair(struct diff_filepair *pair)
+{
         files++;
+        lines_added = 0;
+        lines_removed = 0;
+        cgit_diff_files(pair->one->sha1, pair->two->sha1, cgit_count_diff_lines);
+        if (files >= slots) {
+                if (slots == 0)
+                        slots = 4;
+                else
+                        slots = slots * 2;
+                items = xrealloc(items, slots * sizeof(struct fileinfo));
+        }
+        items[files-1].status = pair->status;
+        hashcpy(items[files-1].old_sha1, pair->one->sha1);
+        hashcpy(items[files-1].new_sha1, pair->two->sha1);
+        items[files-1].old_mode = pair->one->mode;
+        items[files-1].new_mode = pair->two->mode;
+        items[files-1].old_path = xstrdup(pair->one->path);
+        items[files-1].new_path = xstrdup(pair->two->path);
+        items[files-1].added = lines_added;
+        items[files-1].removed = lines_removed;
+        if (lines_added + lines_removed > max_changes)
+                max_changes = lines_added + lines_removed;
+        total_adds += lines_added;
+        total_rems += lines_removed;
 }
 
+
 void cgit_print_commit(const char *hex)
 {
         struct commit *commit;
@@ -94,6 +157,7 @@ void cgit_print_commit(const char *hex)
         unsigned char sha1[20];
         char *query;
         char *filename;
+        int i;
 
         if (get_sha1(hex, sha1)) {
                 cgit_print_error(fmt("Bad object id: %s", hex));
@@ -148,11 +212,17 @@ void cgit_print_commit(const char *hex)
         html("<div class='commit-msg'>");
         html_txt(info->msg);
         html("</div>");
-        html("<table class='diffstat'>");
-        html("<tr><th colspan='3'>Affected files</tr>\n");
-        cgit_diff_commit(commit, print_filepair);
-        htmlf("<tr><td colspan='3' class='summary'>"
-              "%d file%s changed</td></tr>\n", files, files > 1 ? "s" : "");
-        html("</table>");
+        if (!(commit->parents && commit->parents->next && commit->parents->next->next)) {
+                html("<table class='diffstat'>");
+                max_changes = 0;
+                cgit_diff_commit(commit, inspect_filepair);
+                for(i = 0; i<files; i++)
+                        print_fileinfo(&items[i]);
+                html("</table>");
+                html("<div class='diffstat-summary'>");
+                htmlf("%d files changed, %d insertions, %d deletions\n",
+                      files, total_adds, total_rems);
+                html("</div>");
+        }
         cgit_free_commitinfo(info);
 }