+
+/*
+ * Generic support for pretty-printing the header
+ */
+static int get_one_line(const char *msg, unsigned long len)
+{
+ int ret = 0;
+
+ while (len--) {
+ char c = *msg++;
+ ret++;
+ if (c == '\n')
+ break;
+ if (!c)
+ return 0;
+ }
+ return ret;
+}
+
+static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
+{
+ char *date;
+ int namelen;
+ unsigned long time;
+ int tz, ret;
+
+ if (fmt == CMIT_FMT_ONELINE)
+ return 0;
+ date = strchr(line, '>');
+ if (!date)
+ return 0;
+ namelen = ++date - line;
+ time = strtoul(date, &date, 10);
+ tz = strtol(date, NULL, 10);
+
+ ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
+ if (fmt == CMIT_FMT_MEDIUM)
+ ret += sprintf(buf + ret, "Date: %s\n", show_date(time, tz));
+ return ret;
+}
+
+static int is_empty_line(const char *line, int len)
+{
+ while (len && isspace(line[len-1]))
+ len--;
+ return !len;
+}
+
+static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
+{
+ int offset = 0;
+
+ if (fmt == CMIT_FMT_ONELINE)
+ return offset;
+ switch (parents) {
+ case 1:
+ break;
+ case 2:
+ /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
+ offset = sprintf(buf, "Merge: %.40s\n", line-41);
+ /* Fallthrough */
+ default:
+ /* Replace the previous '\n' with a space */
+ buf[offset-1] = ' ';
+ offset += sprintf(buf + offset, "%.40s\n", line+7);
+ }
+ return offset;
+}
+
+unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
+{
+ int hdr = 1, body = 0;
+ unsigned long offset = 0;
+ int parents = 0;
+ int indent = (fmt == CMIT_FMT_ONELINE) ? 0 : 4;
+
+ for (;;) {
+ const char *line = msg;
+ int linelen = get_one_line(msg, len);
+
+ if (!linelen)
+ break;
+
+ /*
+ * We want some slop for indentation and a possible
+ * final "...". Thus the "+ 20".
+ */
+ if (offset + linelen + 20 > space) {
+ memcpy(buf + offset, " ...\n", 8);
+ offset += 8;
+ break;
+ }
+
+ msg += linelen;
+ len -= linelen;
+ if (hdr) {
+ if (linelen == 1) {
+ hdr = 0;
+ if (fmt != CMIT_FMT_ONELINE)
+ buf[offset++] = '\n';
+ continue;
+ }
+ if (fmt == CMIT_FMT_RAW) {
+ memcpy(buf + offset, line, linelen);
+ offset += linelen;
+ continue;
+ }
+ if (!memcmp(line, "parent ", 7)) {
+ if (linelen != 48)
+ die("bad parent line in commit");
+ offset += add_parent_info(fmt, buf + offset, line, ++parents);
+ }
+ if (!memcmp(line, "author ", 7))
+ offset += add_user_info("Author", fmt, buf + offset, line + 7);
+ if (fmt == CMIT_FMT_FULL) {
+ if (!memcmp(line, "committer ", 10))
+ offset += add_user_info("Commit", fmt, buf + offset, line + 10);
+ }
+ continue;
+ }
+
+ if (is_empty_line(line, linelen)) {
+ if (!body)
+ continue;
+ if (fmt == CMIT_FMT_SHORT)
+ break;
+ } else {
+ body = 1;
+ }
+
+ memset(buf + offset, ' ', indent);
+ memcpy(buf + offset + indent, line, linelen);
+ offset += linelen + indent;
+ if (fmt == CMIT_FMT_ONELINE)
+ break;
+ }
+ if (fmt == CMIT_FMT_ONELINE) {
+ /* We do not want the terminating newline */
+ if (buf[offset - 1] == '\n')
+ offset--;
+ }
+ else {
+ /* Make sure there is an EOLN */
+ if (buf[offset - 1] != '\n')
+ buf[offset++] = '\n';
+ }
+ buf[offset] = '\0';
+ return offset;
+}
+
+struct commit *pop_commit(struct commit_list **stack)
+{
+ struct commit_list *top = *stack;
+ struct commit *item = top ? top->item : NULL;
+
+ if (top) {
+ *stack = top->next;
+ free(top);
+ }
+ return item;
+}
+
+int count_parents(struct commit * commit)
+{
+ int count = 0;
+ struct commit_list * parents = commit->parents;
+ for (count=0;parents; parents=parents->next,count++)
+ ;
+ return count;
+}
+
+/*
+ * Performs an in-place topological sort on the list supplied.
+ */
+void sort_in_topological_order(struct commit_list ** list)
+{
+ struct commit_list * next = *list;
+ struct commit_list * work = NULL;
+ struct commit_list ** pptr = list;
+ struct sort_node * nodes;
+ struct sort_node * next_nodes;
+ int count = 0;
+
+ /* determine the size of the list */
+ while (next) {
+ next = next->next;
+ count++;
+ }
+ /* allocate an array to help sort the list */
+ nodes = xcalloc(count, sizeof(*nodes));
+ /* link the list to the array */
+ next_nodes = nodes;
+ next=*list;
+ while (next) {
+ next_nodes->list_item = next;
+ next->item->object.util = next_nodes;
+ next_nodes++;
+ next = next->next;
+ }
+ /* update the indegree */
+ next=*list;
+ while (next) {
+ struct commit_list * parents = next->item->parents;
+ while (parents) {
+ struct commit * parent=parents->item;
+ struct sort_node * pn = (struct sort_node *)parent->object.util;
+
+ if (pn)
+ pn->indegree++;
+ parents=parents->next;
+ }
+ next=next->next;
+ }
+ /*
+ * find the tips
+ *
+ * tips are nodes not reachable from any other node in the list
+ *
+ * the tips serve as a starting set for the work queue.
+ */
+ next=*list;
+ while (next) {
+ struct sort_node * node = (struct sort_node *)next->item->object.util;
+
+ if (node->indegree == 0) {
+ commit_list_insert(next->item, &work);
+ }
+ next=next->next;
+ }
+ /* process the list in topological order */
+ while (work) {
+ struct commit * work_item = pop_commit(&work);
+ struct sort_node * work_node = (struct sort_node *)work_item->object.util;
+ struct commit_list * parents = work_item->parents;
+
+ while (parents) {
+ struct commit * parent=parents->item;
+ struct sort_node * pn = (struct sort_node *)parent->object.util;
+
+ if (pn) {
+ /*
+ * parents are only enqueued for emission
+ * when all their children have been emitted thereby
+ * guaranteeing topological order.
+ */
+ pn->indegree--;
+ if (!pn->indegree)
+ commit_list_insert(parent, &work);
+ }
+ parents=parents->next;
+ }
+ /*
+ * work_item is a commit all of whose children
+ * have already been emitted. we can emit it now.
+ */
+ *pptr = work_node->list_item;
+ pptr = &(*pptr)->next;
+ *pptr = NULL;
+ work_item->object.util = NULL;
+ }
+ free(nodes);
+}