2 files changed, 130 insertions, 25 deletions

diff --git a/cgit.css b/cgit.css
index 3f37165..9e6d2a4 100644
--- a/cgit.css
+++ b/cgit.css
@@ -1,692 +1,702 @@
 body, table, form {
         padding: 0em;
         margin: 0em;
 }
 
 body {
         font-family: sans-serif;
         font-size: 10pt;
         color: #333;
         background: white;
         padding: 4px;
 }
 
 a {
         color: blue;
         text-decoration: none;
 }
 
 a:hover {
         text-decoration: underline;
 }
 
 table {
       border-collapse: collapse;
 }
 
 table#header {
         width: 100%;
         margin-bottom: 1em;
 }
 
 table#header td.logo {
         width: 96px;
 }
 
 table#header td.main {
         font-size: 250%;
         padding-left: 10px;
         white-space: nowrap;
 }
 
 table#header td.main a {
         color: #000;
 }
 
 table#header td.form {
         text-align: right;
         vertical-align: bottom;
         padding-right: 1em;
         padding-bottom: 2px;
         white-space: nowrap;
 }
 
 table#header td.form form,
 table#header td.form input,
 table#header td.form select {
         font-size: 90%;
 }
 
 table#header td.sub {
         color: #777;
         border-top: solid 1px #ccc;
         padding-left: 10px;
 }
 
 table.tabs {
         /* border-bottom: solid 2px #ccc; */
         border-collapse: collapse;
         margin-top: 2em;
         margin-bottom: 0px;
         width: 100%;
 }
 
 table.tabs td {
         padding: 0px 1em;
         vertical-align: bottom;
 }
 
 table.tabs td a {
         padding: 2px 0.75em;
         color: #777;
         font-size: 110%;
 }
 
 table.tabs td a.active {
         color: #000;
         background-color: #ccc;
 }
 
 table.tabs td.form {
         text-align: right;
 }
 
 table.tabs td.form form {
         padding-bottom: 2px;
         font-size: 90%;
         white-space: nowrap;
 }
 
 table.tabs td.form input,
 table.tabs td.form select {
         font-size: 90%;
 }
 
 div.content {
         margin: 0px;
         padding: 2em;
         border-top: solid 3px #ccc;
         border-bottom: solid 3px #ccc;
 }
 
 
 table.list {
         width: 100%;
         border: none;
         border-collapse: collapse;
 }
 
 table.list tr {
         background: white;
 }
 
 table.list tr.logheader {
         background: #eee;
 }
 
 table.list tr:hover {
         background: #eee;
 }
 
 table.list tr.nohover:hover {
         background: white;
 }
 
 table.list th {
         font-weight: bold;
         /* color: #888;
         border-top: dashed 1px #888;
         border-bottom: dashed 1px #888;
         */
         padding: 0.1em 0.5em 0.05em 0.5em;
         vertical-align: baseline;
 }
 
 table.list td {
         border: none;
         padding: 0.1em 0.5em 0.1em 0.5em;
 }
 
 table.list td.logsubject {
         font-family: monospace;
         font-weight: bold;
 }
 
 table.list td.logmsg {
         font-family: monospace;
         white-space: pre;
         padding: 1em 0.5em 2em 0.5em;
 }
 
 table.list td a {
         color: black;
 }
 
 table.list td a:hover {
         color: #00f;
 }
 
 img {
         border: none;
 }
 
 input#switch-btn {
         margin: 2px 0px 0px 0px;
 }
 
 td#sidebar input.txt {
         width: 100%;
         margin: 2px 0px 0px 0px;
 }
 
 table#grid {
         margin: 0px;
 }
 
 td#content {
         vertical-align: top;
         padding: 1em 2em 1em 1em;
         border: none;
 }
 
 div#summary {
         vertical-align: top;
         margin-bottom: 1em;
 }
 
 table#downloads {
         float: right;
         border-collapse: collapse;
         border: solid 1px #777;
         margin-left: 0.5em;
         margin-bottom: 0.5em;
 }
 
 table#downloads th {
         background-color: #ccc;
 }
 
 div#blob {
         border: solid 1px black;
 }
 
 div.error {
         color: red;
         font-weight: bold;
         margin: 1em 2em;
 }
 
 a.ls-blob, a.ls-dir, a.ls-mod {
         font-family: monospace;
 }
 
 td.ls-size {
         text-align: right;
         font-family: monospace;
         width: 10em;
 }
 
 td.ls-mode {
         font-family: monospace;
         width: 10em;
 }
 
 table.blob {
         margin-top: 0.5em;
         border-top: solid 1px black;
 }
 
 table.blob td.lines {
         margin: 0; padding: 0 0 0 0.5em;
         vertical-align: top;
         color: black;
 }
 
 table.blob td.linenumbers {
         margin: 0; padding: 0 0.5em 0 0.5em;
         vertical-align: top;
         text-align: right;
         border-right: 1px solid gray;
 }
 
 table.blob pre {
         padding: 0; margin: 0;
 }
 
 table.blob a.no {
         color: gray;
         text-align: right;
         text-decoration: none;
 }
 
 table.blob a.no a:hover {
         color: black;
 }
 
 table.bin-blob {
         margin-top: 0.5em;
         border: solid 1px black;
 }
 
 table.bin-blob th {
         font-family: monospace;
         white-space: pre;
         border: solid 1px #777;
         padding: 0.5em 1em;
 }
 
 table.bin-blob td {
         font-family: monospace;
         white-space: pre;
         border-left: solid 1px #777;
         padding: 0em 1em;
 }
 
 table.nowrap td {
         white-space: nowrap;
 }
 
 table.commit-info {
         border-collapse: collapse;
         margin-top: 1.5em;
 }
 
 table.commit-info th {
         text-align: left;
         font-weight: normal;
         padding: 0.1em 1em 0.1em 0.1em;
         vertical-align: top;
 }
 
 table.commit-info td {
         font-weight: normal;
         padding: 0.1em 1em 0.1em 0.1em;
 }
 
 div.commit-subject {
         font-weight: bold;
         font-size: 125%;
         margin: 1.5em 0em 0.5em 0em;
         padding: 0em;
 }
 
 div.commit-msg {
         white-space: pre;
         font-family: monospace;
 }
 
 div.diffstat-header {
         font-weight: bold;
         padding-top: 1.5em;
 }
 
 table.diffstat {
         border-collapse: collapse;
         border: solid 1px #aaa;
         background-color: #eee;
 }
 
 table.diffstat th {
         font-weight: normal;
         text-align: left;
         text-decoration: underline;
         padding: 0.1em 1em 0.1em 0.1em;
         font-size: 100%;
 }
 
 table.diffstat td {
         padding: 0.2em 0.2em 0.1em 0.1em;
         font-size: 100%;
         border: none;
 }
 
 table.diffstat td.mode {
         white-space: nowrap;
 }
 
 table.diffstat td span.modechange {
         padding-left: 1em;
         color: red;
 }
 
 table.diffstat td.add a {
         color: green;
 }
 
 table.diffstat td.del a {
         color: red;
 }
 
 table.diffstat td.upd a {
         color: blue;
 }
 
 table.diffstat td.graph {
         width: 500px;
         vertical-align: middle;
 }
 
 table.diffstat td.graph table {
         border: none;
 }
 
 table.diffstat td.graph td {
         padding: 0px;
         border: 0px;
         height: 7pt;
 }
 
 table.diffstat td.graph td.add {
         background-color: #5c5;
 }
 
 table.diffstat td.graph td.rem {
         background-color: #c55;
 }
 
 div.diffstat-summary {
         color: #888;
         padding-top: 0.5em;
 }
 
 table.diff {
         width: 100%;
 }
 
 table.diff td {
         font-family: monospace;
         white-space: pre;
 }
 
 table.diff td div.head {
         font-weight: bold;
         margin-top: 1em;
         color: black;
 }
 
 table.diff td div.hunk {
         color: #009;
 }
 
 table.diff td div.add {
         color: green;
 }
 
 table.diff td div.del {
         color: red;
 }
 
 .sha1 {
         font-family: monospace;
         font-size: 90%;
 }
 
 .left {
         text-align: left;
 }
 
 .right {
         text-align: right;
 }
 
 table.list td.reposection {
         font-style: italic;
         color: #888;
 }
 
 a.button {
         font-size: 80%;
         padding: 0em 0.5em;
 }
 
 a.primary {
         font-size: 100%;
 }
 
 a.secondary {
         font-size: 90%;
 }
 
 td.toplevel-repo {
 
 }
 
 table.list td.sublevel-repo {
         padding-left: 1.5em;
 }
 
 div.pager {
         text-align: center;
         margin: 1em 0em 0em 0em;
 }
 
 div.pager a {
         color: #777;
         margin: 0em 0.5em;
 }
 
 span.age-mins {
         font-weight: bold;
         color: #080;
 }
 
 span.age-hours {
         color: #080;
 }
 
 span.age-days {
         color: #040;
 }
 
 span.age-weeks {
         color: #444;
 }
 
 span.age-months {
         color: #888;
 }
 
 span.age-years {
         color: #bbb;
 }
 div.footer {
         margin-top: 0.5em;
         text-align: center;
         font-size: 80%;
         color: #ccc;
 }
 a.branch-deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #88ff88;
         border: solid 1px #007700;
 }
 a.tag-deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #ffff88;
         border: solid 1px #777700;
 }
 a.remote-deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #ccccff;
         border: solid 1px #000077;
 }
 a.deco {
         margin: 0px 0.5em;
         padding: 0px 0.25em;
         background-color: #ff8888;
         border: solid 1px #770000;
 }
 
 div.commit-subject a {
         margin-left: 1em;
         font-size: 75%;
 }
 
 table.stats {
         border: solid 1px black;
         border-collapse: collapse;
 }
 
 table.stats th {
         text-align: left;
         padding: 1px 0.5em;
         background-color: #eee;
         border: solid 1px black;
 }
 
 table.stats td {
         text-align: right;
         padding: 1px 0.5em;
         border: solid 1px black;
 }
 
 table.stats td.total {
         font-weight: bold;
         text-align: left;
 }
 
 table.stats td.sum {
         color: #c00;
         font-weight: bold;
         /*background-color: #eee; */
 }
 
 table.stats td.left {
         text-align: left;
 }
 
 table.vgraph {
         border-collapse: separate;
         border: solid 1px black;
         height: 200px;
 }
 
 table.vgraph th {
         background-color: #eee;
         font-weight: bold;
         border: solid 1px white;
         padding: 1px 0.5em;
 }
 
 table.vgraph td {
         vertical-align: bottom;
         padding: 0px 10px;
 }
 
 table.vgraph div.bar {
         background-color: #eee;
 }
 
 table.hgraph {
         border: solid 1px black;
         width: 800px;
 }
 
 table.hgraph th {
         background-color: #eee;
         font-weight: bold;
         border: solid 1px black;
         padding: 1px 0.5em;
 }
 
 table.hgraph td {
         vertical-align: center;
         padding: 2px 2px;
 }
 
 table.hgraph div.bar {
         background-color: #eee;
         height: 1em;
 }
 
 table.ssdiff {
         width: 100%;
 }
 
 table.ssdiff td {
         font-size: 75%;
         font-family: monospace;
         white-space: pre;
         padding: 1px 4px 1px 4px;
         border-left: solid 1px #aaa;
         border-right: solid 1px #aaa;
 }
 
 table.ssdiff td.add {
         color: black;
         background: #cfc;
         min-width: 50%;
 }
 
 table.ssdiff td.add_dark {
         color: black;
         background: #aca;
         min-width: 50%;
 }
 
+table.ssdiff span.add {
+        background: #cfc;
+        font-weight: bold;
+}
+
 table.ssdiff td.del {
         color: black;
         background: #fcc;
         min-width: 50%;
 }
 
 table.ssdiff td.del_dark {
         color: black;
         background: #caa;
         min-width: 50%;
 }
 
+table.ssdiff span.del {
+        background: #fcc;
+        font-weight: bold;
+}
+
 table.ssdiff td.changed {
         color: black;
         background: #ffc;
         min-width: 50%;
 }
 
 table.ssdiff td.changed_dark {
         color: black;
         background: #cca;
         min-width: 50%;
 }
 
 table.ssdiff td.lineno {
         color: black;
         background: #eee;
         text-align: right;
         width: 3em;
         min-width: 3em;
 }
 
 table.ssdiff td.hunk {
         color: #black;
         background: #ccf;
         border-top: solid 1px #aaa;
         border-bottom: solid 1px #aaa;
 }
 
 table.ssdiff td.head {
         border-top: solid 1px #aaa;
         border-bottom: solid 1px #aaa;
 }
 
 table.ssdiff td.head div.head {
         font-weight: bold;
         color: black;
 }
 
 table.ssdiff td.foot {
         border-top: solid 1px #aaa;
         border-left: none;
         border-right: none;
         border-bottom: none;
 }
 
 table.ssdiff td.space {
         border: none;
 }
 
 table.ssdiff td.space div {
         min-height: 3em;
 }
\ No newline at end of file
diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index 5673642..408e620 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -1,274 +1,369 @@
 #include "cgit.h"
 #include "html.h"
 #include "ui-shared.h"
 
 extern int use_ssdiff;
 
 static int current_old_line, current_new_line;
 
 struct deferred_lines {
         int line_no;
         char *line;
         struct deferred_lines *next;
 };
 
 static struct deferred_lines *deferred_old, *deferred_old_last;
 static struct deferred_lines *deferred_new, *deferred_new_last;
 
+static char *longest_common_subsequence(char *A, char *B)
+{
+        int i, j, ri;
+        int m = strlen(A);
+        int n = strlen(B);
+        int L[m + 1][n + 1];
+        int tmp1, tmp2;
+        int lcs_length;
+        char *result;
+
+        for (i = m; i >= 0; i--) {
+                for (j = n; j >= 0; j--) {
+                        if (A[i] == '\0' || B[j] == '\0') {
+                                L[i][j] = 0;
+                        } else if (A[i] == B[j]) {
+                                L[i][j] = 1 + L[i + 1][j + 1];
+                        } else {
+                                tmp1 = L[i + 1][j];
+                                tmp2 = L[i][j + 1];
+                                L[i][j] = (tmp1 > tmp2 ? tmp1 : tmp2);
+                        }
+                }
+        }
+
+        lcs_length = L[0][0];
+        result = xmalloc(lcs_length + 2);
+        memset(result, 0, sizeof(*result) * (lcs_length + 2));
+
+        ri = 0;
+        i = 0;
+        j = 0;
+        while (i < m && j < n) {
+                if (A[i] == B[j]) {
+                        result[ri] = A[i];
+                        ri += 1;
+                        i += 1;
+                        j += 1;
+                } else if (L[i + 1][j] >= L[i][j + 1]) {
+                        i += 1;
+                } else {
+                        j += 1;
+                }
+        }
+        return result;
+}
+
 static int line_from_hunk(char *line, char type)
 {
         char *buf1, *buf2;
         int len;
 
         buf1 = strchr(line, type);
         if (buf1 == NULL)
                 return 0;
         buf1 += 1;
         buf2 = strchr(buf1, ',');
         if (buf2 == NULL)
                 return 0;
         len = buf2 - buf1;
         buf2 = xmalloc(len + 1);
         strncpy(buf2, buf1, len);
         buf2[len] = '\0';
         int res = atoi(buf2);
         free(buf2);
         return res;
 }
 
 static char *replace_tabs(char *line)
 {
         char *prev_buf = line;
         char *cur_buf;
         int linelen = strlen(line);
         int n_tabs = 0;
         int i;
         char *result;
         char *spaces = "        ";
 
         if (linelen == 0) {
                 result = xmalloc(1);
                 result[0] = '\0';
                 return result;
         }
 
         for (i = 0; i < linelen; i++)
                 if (line[i] == '\t')
                         n_tabs += 1;
         result = xmalloc(linelen + n_tabs * 8 + 1);
         result[0] = '\0';
 
         while (1) {
                 cur_buf = strchr(prev_buf, '\t');
                 if (!cur_buf) {
                         strcat(result, prev_buf);
                         break;
                 } else {
                         strcat(result, " ");
                         strncat(result, spaces, 8 - (strlen(result) % 8));
                         strncat(result, prev_buf, cur_buf - prev_buf);
                 }
                 prev_buf = cur_buf + 1;
         }
         return result;
 }
 
+static int calc_deferred_lines(struct deferred_lines *start)
+{
+        struct deferred_lines *item = start;
+        int result = 0;
+        while (item) {
+                result += 1;
+                item = item->next;
+        }
+        return result;
+}
+
 static void deferred_old_add(char *line, int line_no)
 {
         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
         item->line = xstrdup(line);
         item->line_no = line_no;
         item->next = NULL;
         if (deferred_old) {
                 deferred_old_last->next = item;
                 deferred_old_last = item;
         } else {
                 deferred_old = deferred_old_last = item;
         }
 }
 
 static void deferred_new_add(char *line, int line_no)
 {
         struct deferred_lines *item = xmalloc(sizeof(struct deferred_lines));
         item->line = xstrdup(line);
         item->line_no = line_no;
         item->next = NULL;
         if (deferred_new) {
                 deferred_new_last->next = item;
                 deferred_new_last = item;
         } else {
                 deferred_new = deferred_new_last = item;
         }
 }
 
-static void print_ssdiff_line(char *class, int old_line_no, char *old_line,
-                              int new_line_no, char *new_line)
+static void print_part_with_lcs(char *class, char *line, char *lcs)
+{
+        int line_len = strlen(line);
+        int i, j;
+        char c[2] = " ";
+        int same = 1;
+
+        j = 0;
+        for (i = 0; i < line_len; i++) {
+                c[0] = line[i];
+                if (same) {
+                        if (line[i] == lcs[j])
+                                j += 1;
+                        else {
+                                same = 0;
+                                htmlf("<span class='%s'>", class);
+                        }
+                } else if (line[i] == lcs[j]) {
+                        same = 1;
+                        htmlf("</span>");
+                        j += 1;
+                }
+                html_txt(c);
+        }
+}
+
+static void print_ssdiff_line(char *class,
+                              int old_line_no,
+                              char *old_line,
+                              int new_line_no,
+                              char *new_line, int individual_chars)
 {
+        char *lcs = NULL;
+        if (old_line)
+                old_line = replace_tabs(old_line + 1);
+        if (new_line)
+                new_line = replace_tabs(new_line + 1);
+        if (individual_chars && old_line && new_line)
+                lcs = longest_common_subsequence(old_line, new_line);
         html("<tr>");
         if (old_line_no > 0)
                 htmlf("<td class='lineno'>%d</td><td class='%s'>",
                       old_line_no, class);
         else if (old_line)
                 htmlf("<td class='lineno'></td><td class='%s'>", class);
         else
                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
-
         if (old_line) {
-                old_line = replace_tabs(old_line + 1);
-                html_txt(old_line);
-                free(old_line);
+                if (lcs)
+                        print_part_with_lcs("del", old_line, lcs);
+                else
+                        html_txt(old_line);
         }
 
         html("</td>");
-
         if (new_line_no > 0)
                 htmlf("<td class='lineno'>%d</td><td class='%s'>",
                       new_line_no, class);
         else if (new_line)
                 htmlf("<td class='lineno'></td><td class='%s'>", class);
         else
                 htmlf("<td class='lineno'></td><td class='%s_dark'>", class);
-
         if (new_line) {
-                new_line = replace_tabs(new_line + 1);
-                html_txt(new_line);
-                free(new_line);
+                if (lcs)
+                        print_part_with_lcs("add", new_line, lcs);
+                else
+                        html_txt(new_line);
         }
 
         html("</td></tr>");
+        if (lcs)
+                free(lcs);
+        if (new_line)
+                free(new_line);
+        if (old_line)
+                free(old_line);
 }
 
 static void print_deferred_old_lines()
 {
         struct deferred_lines *iter_old, *tmp;
-
         iter_old = deferred_old;
         while (iter_old) {
                 print_ssdiff_line("del", iter_old->line_no,
-                                  iter_old->line, -1, NULL);
+                                  iter_old->line, -1, NULL, 0);
                 tmp = iter_old->next;
                 free(iter_old);
                 iter_old = tmp;
         }
 }
 
 static void print_deferred_new_lines()
 {
         struct deferred_lines *iter_new, *tmp;
-
         iter_new = deferred_new;
         while (iter_new) {
-                print_ssdiff_line("add", -1, NULL, iter_new->line_no,
-                                  iter_new->line);
+                print_ssdiff_line("add", -1, NULL,
+                                  iter_new->line_no, iter_new->line, 0);
                 tmp = iter_new->next;
                 free(iter_new);
                 iter_new = tmp;
         }
 }
 
 static void print_deferred_changed_lines()
 {
         struct deferred_lines *iter_old, *iter_new, *tmp;
+        int n_old_lines = calc_deferred_lines(deferred_old);
+        int n_new_lines = calc_deferred_lines(deferred_new);
+        int individual_chars = (n_old_lines == n_new_lines ? 1 : 0);
 
         iter_old = deferred_old;
         iter_new = deferred_new;
         while (iter_old || iter_new) {
                 if (iter_old && iter_new)
                         print_ssdiff_line("changed", iter_old->line_no,
                                           iter_old->line,
-                                          iter_new->line_no, iter_new->line);
+                                          iter_new->line_no, iter_new->line,
+                                          individual_chars);
                 else if (iter_old)
                         print_ssdiff_line("changed", iter_old->line_no,
-                                          iter_old->line, -1, NULL);
+                                          iter_old->line, -1, NULL, 0);
                 else if (iter_new)
                         print_ssdiff_line("changed", -1, NULL,
-                                          iter_new->line_no, iter_new->line);
-
+                                          iter_new->line_no, iter_new->line, 0);
                 if (iter_old) {
                         tmp = iter_old->next;
                         free(iter_old);
                         iter_old = tmp;
                 }
 
                 if (iter_new) {
                         tmp = iter_new->next;
                         free(iter_new);
                         iter_new = tmp;
                 }
         }
 }
 
 void cgit_ssdiff_print_deferred_lines()
 {
         if (!deferred_old && !deferred_new)
                 return;
-
         if (deferred_old && !deferred_new)
                 print_deferred_old_lines();
         else if (!deferred_old && deferred_new)
                 print_deferred_new_lines();
         else
                 print_deferred_changed_lines();
-
         deferred_old = deferred_old_last = NULL;
         deferred_new = deferred_new_last = NULL;
 }
 
 /*
  * print a single line returned from xdiff
  */
 void cgit_ssdiff_line_cb(char *line, int len)
 {
         char c = line[len - 1];
-
         line[len - 1] = '\0';
-
         if (line[0] == '@') {
                 current_old_line = line_from_hunk(line, '-');
                 current_new_line = line_from_hunk(line, '+');
         }
 
         if (line[0] == ' ') {
                 if (deferred_old || deferred_new)
                         cgit_ssdiff_print_deferred_lines();
                 print_ssdiff_line("ctx", current_old_line, line,
-                                  current_new_line, line);
+                                  current_new_line, line, 0);
                 current_old_line += 1;
                 current_new_line += 1;
         } else if (line[0] == '+') {
                 deferred_new_add(line, current_new_line);
                 current_new_line += 1;
         } else if (line[0] == '-') {
                 deferred_old_add(line, current_old_line);
                 current_old_line += 1;
         } else if (line[0] == '@') {
                 html("<tr><td colspan='4' class='hunk'>");
                 html_txt(line);
                 html("</td></tr>");
         } else {
                 html("<tr><td colspan='4' class='ctx'>");
                 html_txt(line);
                 html("</td></tr>");
         }
         line[len - 1] = c;
 }
 
 void cgit_ssdiff_header_begin()
 {
         current_old_line = -1;
         current_new_line = -1;
         html("<tr><td class='space' colspan='4'><div></div></td></tr>");
         html("<tr><td class='head' colspan='4'>");
 }
 
 void cgit_ssdiff_header_end()
 {
         html("</td><tr>");
 }
 
 void cgit_ssdiff_footer()
 {
         if (deferred_old || deferred_new)
                 cgit_ssdiff_print_deferred_lines();
         html("<tr><td class='foot' colspan='4'></td></tr>");
 }