git-show-branch doc: show -g as synonym to --reflog in the list
[gitweb.git] / graph.c
diff --git a/graph.c b/graph.c
index add7e4477dfeb5715a13069d233365c8d2dce2c3..162a516ee15cca1f8ab118dd41b803a5d76e42ff 100644 (file)
--- a/graph.c
+++ b/graph.c
@@ -4,6 +4,43 @@
 #include "diff.h"
 #include "revision.h"
 
+/* Internal API */
+
+/*
+ * Output the next line for a graph.
+ * This formats the next graph line into the specified strbuf.  It is not
+ * terminated with a newline.
+ *
+ * Returns 1 if the line includes the current commit, and 0 otherwise.
+ * graph_next_line() will return 1 exactly once for each time
+ * graph_update() is called.
+ */
+static int graph_next_line(struct git_graph *graph, struct strbuf *sb);
+
+/*
+ * Output a padding line in the graph.
+ * This is similar to graph_next_line().  However, it is guaranteed to
+ * never print the current commit line.  Instead, if the commit line is
+ * next, it will simply output a line of vertical padding, extending the
+ * branch lines downwards, but leaving them otherwise unchanged.
+ */
+static void graph_padding_line(struct git_graph *graph, struct strbuf *sb);
+
+/*
+ * Print a strbuf to stdout.  If the graph is non-NULL, all lines but the
+ * first will be prefixed with the graph output.
+ *
+ * If the strbuf ends with a newline, the output will end after this
+ * newline.  A new graph line will not be printed after the final newline.
+ * If the strbuf is empty, no output will be printed.
+ *
+ * Since the first line will not include the graph ouput, the caller is
+ * responsible for printing this line's graph (perhaps via
+ * graph_show_commit() or graph_show_oneline()) before calling
+ * graph_show_strbuf().
+ */
+static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb);
+
 /*
  * TODO:
  * - Add colors to the graph.
@@ -54,6 +91,8 @@ struct git_graph {
         * The commit currently being processed
         */
        struct commit *commit;
+       /* The rev-info used for the current traversal */
+       struct rev_info *revs;
        /*
         * The number of interesting parents that this commit has.
         *
@@ -78,6 +117,27 @@ struct git_graph {
         * This tells us what kind of line graph_next_line() should output.
         */
        enum graph_state state;
+       /*
+        * The output state for the previous line of output.
+        * This is primarily used to determine how the first merge line
+        * should appear, based on the last line of the previous commit.
+        */
+       enum graph_state prev_state;
+       /*
+        * The index of the column that refers to this commit.
+        *
+        * If none of the incoming columns refer to this commit,
+        * this will be equal to num_columns.
+        */
+       int commit_index;
+       /*
+        * The commit_index for the previously displayed commit.
+        *
+        * This is used to determine how the first line of a merge
+        * graph output should appear, based on the last line of the
+        * previous commit.
+        */
+       int prev_commit_index;
        /*
         * The maximum number of columns that can be stored in the columns
         * and new_columns arrays.  This is also half the number of entries
@@ -127,13 +187,17 @@ struct git_graph {
        int *new_mapping;
 };
 
-struct git_graph *graph_init(void)
+struct git_graph *graph_init(struct rev_info *opt)
 {
        struct git_graph *graph = xmalloc(sizeof(struct git_graph));
        graph->commit = NULL;
+       graph->revs = opt;
        graph->num_parents = 0;
        graph->expansion_row = 0;
        graph->state = GRAPH_PADDING;
+       graph->prev_state = GRAPH_PADDING;
+       graph->commit_index = 0;
+       graph->prev_commit_index = 0;
        graph->num_columns = 0;
        graph->num_new_columns = 0;
        graph->mapping_size = 0;
@@ -153,12 +217,10 @@ struct git_graph *graph_init(void)
        return graph;
 }
 
-void graph_release(struct git_graph *graph)
+static void graph_update_state(struct git_graph *graph, enum graph_state s)
 {
-       free(graph->columns);
-       free(graph->new_columns);
-       free(graph->mapping);
-       free(graph);
+       graph->prev_state = graph->state;
+       graph->state = s;
 }
 
 static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
@@ -186,26 +248,76 @@ static void graph_ensure_capacity(struct git_graph *graph, int num_columns)
  * Returns 1 if the commit will be printed in the graph output,
  * and 0 otherwise.
  */
-static int graph_is_interesting(struct commit *commit)
+static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
 {
+       /*
+        * If revs->boundary is set, commits whose children have
+        * been shown are always interesting, even if they have the
+        * UNINTERESTING or TREESAME flags set.
+        */
+       if (graph->revs && graph->revs->boundary) {
+               if (commit->object.flags & CHILD_SHOWN)
+                       return 1;
+       }
+
        /*
         * Uninteresting and pruned commits won't be printed
         */
        return (commit->object.flags & (UNINTERESTING | TREESAME)) ? 0 : 1;
 }
 
+static struct commit_list *next_interesting_parent(struct git_graph *graph,
+                                                  struct commit_list *orig)
+{
+       struct commit_list *list;
+
+       /*
+        * If revs->first_parent_only is set, only the first
+        * parent is interesting.  None of the others are.
+        */
+       if (graph->revs->first_parent_only)
+               return NULL;
+
+       /*
+        * Return the next interesting commit after orig
+        */
+       for (list = orig->next; list; list = list->next) {
+               if (graph_is_interesting(graph, list->item))
+                       return list;
+       }
+
+       return NULL;
+}
+
+static struct commit_list *first_interesting_parent(struct git_graph *graph)
+{
+       struct commit_list *parents = graph->commit->parents;
+
+       /*
+        * If this commit has no parents, ignore it
+        */
+       if (!parents)
+               return NULL;
+
+       /*
+        * If the first parent is interesting, return it
+        */
+       if (graph_is_interesting(graph, parents->item))
+               return parents;
+
+       /*
+        * Otherwise, call next_interesting_parent() to get
+        * the next interesting parent
+        */
+       return next_interesting_parent(graph, parents);
+}
+
 static void graph_insert_into_new_columns(struct git_graph *graph,
                                          struct commit *commit,
                                          int *mapping_index)
 {
        int i;
 
-       /*
-        * Ignore uinteresting commits
-        */
-       if (!graph_is_interesting(commit))
-               return;
-
        /*
         * If the commit is already in the new_columns list, we don't need to
         * add it.  Just update the mapping correctly.
@@ -329,9 +441,10 @@ static void graph_update_columns(struct git_graph *graph)
                if (col_commit == graph->commit) {
                        int old_mapping_idx = mapping_idx;
                        seen_this = 1;
-                       for (parent = graph->commit->parents;
+                       graph->commit_index = i;
+                       for (parent = first_interesting_parent(graph);
                             parent;
-                            parent = parent->next) {
+                            parent = next_interesting_parent(graph, parent)) {
                                graph_insert_into_new_columns(graph,
                                                              parent->item,
                                                              &mapping_idx);
@@ -376,11 +489,20 @@ void graph_update(struct git_graph *graph, struct commit *commit)
         * Count how many interesting parents this commit has
         */
        graph->num_parents = 0;
-       for (parent = commit->parents; parent; parent = parent->next) {
-               if (graph_is_interesting(parent->item))
-                       graph->num_parents++;
+       for (parent = first_interesting_parent(graph);
+            parent;
+            parent = next_interesting_parent(graph, parent))
+       {
+               graph->num_parents++;
        }
 
+       /*
+        * Store the old commit_index in prev_commit_index.
+        * graph_update_columns() will update graph->commit_index for this
+        * commit.
+        */
+       graph->prev_commit_index = graph->commit_index;
+
        /*
         * Call graph_update_columns() to update
         * columns, new_columns, and mapping.
@@ -391,21 +513,26 @@ void graph_update(struct git_graph *graph, struct commit *commit)
 
        /*
         * Update graph->state.
+        * Note that we don't call graph_update_state() here, since
+        * we don't want to update graph->prev_state.  No line for
+        * graph->state was ever printed.
         *
         * If the previous commit didn't get to the GRAPH_PADDING state,
         * it never finished its output.  Goto GRAPH_SKIP, to print out
         * a line to indicate that portion of the graph is missing.
         *
-        * Otherwise, if there are 3 or more parents, we need to print
-        * extra rows before the commit, to expand the branch lines around
-        * it and make room for it.
+        * If there are 3 or more parents, we may need to print extra rows
+        * before the commit, to expand the branch lines around it and make
+        * room for it.  We need to do this only if there is a branch row
+        * (or more) to the right of this commit.
         *
         * If there are less than 3 parents, we can immediately print the
         * commit line.
         */
        if (graph->state != GRAPH_PADDING)
                graph->state = GRAPH_SKIP;
-       else if (graph->num_parents >= 3)
+       else if (graph->num_parents >= 3 &&
+                graph->commit_index < (graph->num_columns - 1))
                graph->state = GRAPH_PRE_COMMIT;
        else
                graph->state = GRAPH_COMMIT;
@@ -484,10 +611,11 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
        strbuf_addstr(sb, "...");
        graph_pad_horizontally(graph, sb);
 
-       if (graph->num_parents >= 3)
-               graph->state = GRAPH_PRE_COMMIT;
+       if (graph->num_parents >= 3 &&
+           graph->commit_index < (graph->num_columns - 1))
+               graph_update_state(graph, GRAPH_PRE_COMMIT);
        else
-               graph->state = GRAPH_COMMIT;
+               graph_update_state(graph, GRAPH_COMMIT);
 }
 
 static void graph_output_pre_commit_line(struct git_graph *graph,
@@ -522,7 +650,22 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
                if (col->commit == graph->commit) {
                        seen_this = 1;
                        strbuf_addf(sb, "| %*s", graph->expansion_row, "");
-               } else if (seen_this) {
+               } else if (seen_this && (graph->expansion_row == 0)) {
+                       /*
+                        * This is the first line of the pre-commit output.
+                        * If the previous commit was a merge commit and
+                        * ended in the GRAPH_POST_MERGE state, all branch
+                        * lines after graph->prev_commit_index were
+                        * printed as "\" on the previous line.  Continue
+                        * to print them as "\" on this line.  Otherwise,
+                        * print the branch lines as "|".
+                        */
+                       if (graph->prev_state == GRAPH_POST_MERGE &&
+                           graph->prev_commit_index < i)
+                               strbuf_addstr(sb, "\\ ");
+                       else
+                               strbuf_addstr(sb, "| ");
+               } else if (seen_this && (graph->expansion_row > 0)) {
                        strbuf_addstr(sb, "\\ ");
                } else {
                        strbuf_addstr(sb, "| ");
@@ -537,10 +680,41 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
         */
        graph->expansion_row++;
        if (graph->expansion_row >= num_expansion_rows)
-               graph->state = GRAPH_COMMIT;
+               graph_update_state(graph, GRAPH_COMMIT);
 }
 
-void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
+{
+       /*
+        * For boundary commits, print 'o'
+        * (We should only see boundary commits when revs->boundary is set.)
+        */
+       if (graph->commit->object.flags & BOUNDARY) {
+               assert(graph->revs->boundary);
+               strbuf_addch(sb, 'o');
+               return;
+       }
+
+       /*
+        * If revs->left_right is set, print '<' for commits that
+        * come from the left side, and '>' for commits from the right
+        * side.
+        */
+       if (graph->revs && graph->revs->left_right) {
+               if (graph->commit->object.flags & SYMMETRIC_LEFT)
+                       strbuf_addch(sb, '<');
+               else
+                       strbuf_addch(sb, '>');
+               return;
+       }
+
+       /*
+        * Print '*' in all other cases
+        */
+       strbuf_addch(sb, '*');
+}
+
+static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 {
        int seen_this = 0;
        int i, j;
@@ -565,24 +739,10 @@ void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 
                if (col_commit == graph->commit) {
                        seen_this = 1;
-                       /*
-                        * If the commit has more than 1 interesting
-                        * parent, print 'M' to indicate that it is a
-                        * merge.  Otherwise, print '*'.
-                        *
-                        * Note that even if this is actually a merge
-                        * commit, we still print '*' if less than 2 of its
-                        * parents are interesting.
-                        */
-                       if (graph->num_parents > 1)
-                               strbuf_addch(sb, 'M');
-                       else
-                               strbuf_addch(sb, '*');
+                       graph_output_commit_char(graph, sb);
 
-                       if (graph->num_parents < 2)
+                       if (graph->num_parents < 3)
                                strbuf_addch(sb, ' ');
-                       else if (graph->num_parents == 2)
-                               strbuf_addstr(sb, "  ");
                        else {
                                int num_dashes =
                                        ((graph->num_parents - 2) * 2) - 1;
@@ -590,8 +750,27 @@ void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
                                        strbuf_addch(sb, '-');
                                strbuf_addstr(sb, ". ");
                        }
-               } else if (seen_this && (graph->num_parents > 1)) {
+               } else if (seen_this && (graph->num_parents > 2)) {
                        strbuf_addstr(sb, "\\ ");
+               } else if (seen_this && (graph->num_parents == 2)) {
+                       /*
+                        * This is a 2-way merge commit.
+                        * There is no GRAPH_PRE_COMMIT stage for 2-way
+                        * merges, so this is the first line of output
+                        * for this commit.  Check to see what the previous
+                        * line of output was.
+                        *
+                        * If it was GRAPH_POST_MERGE, the branch line
+                        * coming into this commit may have been '\',
+                        * and not '|' or '/'.  If so, output the branch
+                        * line as '\' on this line, instead of '|'.  This
+                        * makes the output look nicer.
+                        */
+                       if (graph->prev_state == GRAPH_POST_MERGE &&
+                           graph->prev_commit_index < i)
+                               strbuf_addstr(sb, "\\ ");
+                       else
+                               strbuf_addstr(sb, "| ");
                } else {
                        strbuf_addstr(sb, "| ");
                }
@@ -603,14 +782,14 @@ void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
         * Update graph->state
         */
        if (graph->num_parents > 1)
-               graph->state = GRAPH_POST_MERGE;
+               graph_update_state(graph, GRAPH_POST_MERGE);
        else if (graph_is_mapping_correct(graph))
-               graph->state = GRAPH_PADDING;
+               graph_update_state(graph, GRAPH_PADDING);
        else
-               graph->state = GRAPH_COLLAPSING;
+               graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
-void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
 {
        int seen_this = 0;
        int i, j;
@@ -633,9 +812,7 @@ void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
                        strbuf_addch(sb, '|');
                        for (j = 0; j < graph->num_parents - 1; j++)
                                strbuf_addstr(sb, "\\ ");
-                       if (graph->num_parents == 2)
-                               strbuf_addch(sb, ' ');
-               } else if (seen_this && (graph->num_parents > 2)) {
+               } else if (seen_this) {
                        strbuf_addstr(sb, "\\ ");
                } else {
                        strbuf_addstr(sb, "| ");
@@ -648,12 +825,12 @@ void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
         * Update graph->state
         */
        if (graph_is_mapping_correct(graph))
-               graph->state = GRAPH_PADDING;
+               graph_update_state(graph, GRAPH_PADDING);
        else
-               graph->state = GRAPH_COLLAPSING;
+               graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
-void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
 {
        int i;
        int *tmp_mapping;
@@ -755,10 +932,10 @@ void graph_output_collapsing_line(struct git_graph *graph, struct strbuf *sb)
         * Otherwise, we need to collapse some branch lines together.
         */
        if (graph_is_mapping_correct(graph))
-               graph->state = GRAPH_PADDING;
+               graph_update_state(graph, GRAPH_PADDING);
 }
 
-int graph_next_line(struct git_graph *graph, struct strbuf *sb)
+static int graph_next_line(struct git_graph *graph, struct strbuf *sb)
 {
        switch (graph->state) {
        case GRAPH_PADDING:
@@ -785,7 +962,7 @@ int graph_next_line(struct git_graph *graph, struct strbuf *sb)
        return 0;
 }
 
-void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 {
        int i, j;
 
@@ -819,6 +996,11 @@ void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
        }
 
        graph_pad_horizontally(graph, sb);
+
+       /*
+        * Update graph->prev_state since we have output a padding line
+        */
+       graph->prev_state = GRAPH_PADDING;
 }
 
 int graph_is_commit_finished(struct git_graph const *graph)
@@ -828,14 +1010,12 @@ int graph_is_commit_finished(struct git_graph const *graph)
 
 void graph_show_commit(struct git_graph *graph)
 {
-       struct strbuf msgbuf;
+       struct strbuf msgbuf = STRBUF_INIT;
        int shown_commit_line = 0;
 
        if (!graph)
                return;
 
-       strbuf_init(&msgbuf, 0);
-
        while (!shown_commit_line) {
                shown_commit_line = graph_next_line(graph, &msgbuf);
                fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
@@ -849,12 +1029,11 @@ void graph_show_commit(struct git_graph *graph)
 
 void graph_show_oneline(struct git_graph *graph)
 {
-       struct strbuf msgbuf;
+       struct strbuf msgbuf = STRBUF_INIT;
 
        if (!graph)
                return;
 
-       strbuf_init(&msgbuf, 0);
        graph_next_line(graph, &msgbuf);
        fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
        strbuf_release(&msgbuf);
@@ -862,12 +1041,11 @@ void graph_show_oneline(struct git_graph *graph)
 
 void graph_show_padding(struct git_graph *graph)
 {
-       struct strbuf msgbuf;
+       struct strbuf msgbuf = STRBUF_INIT;
 
        if (!graph)
                return;
 
-       strbuf_init(&msgbuf, 0);
        graph_padding_line(graph, &msgbuf);
        fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
        strbuf_release(&msgbuf);
@@ -875,7 +1053,7 @@ void graph_show_padding(struct git_graph *graph)
 
 int graph_show_remainder(struct git_graph *graph)
 {
-       struct strbuf msgbuf;
+       struct strbuf msgbuf = STRBUF_INIT;
        int shown = 0;
 
        if (!graph)
@@ -884,7 +1062,6 @@ int graph_show_remainder(struct git_graph *graph)
        if (graph_is_commit_finished(graph))
                return 0;
 
-       strbuf_init(&msgbuf, 0);
        for (;;) {
                graph_next_line(graph, &msgbuf);
                fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
@@ -902,7 +1079,7 @@ int graph_show_remainder(struct git_graph *graph)
 }
 
 
-void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
+static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb)
 {
        char *p;