do not segfault if make_cache_entry failed
[gitweb.git] / graph.c
diff --git a/graph.c b/graph.c
index 26b8c5209e280697cc35ffd5313fe3e79681fc43..5f821706c63778e8b6b53a10894edfc2fb21a8b0 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.
@@ -80,6 +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
@@ -137,6 +195,9 @@ struct git_graph *graph_init(struct rev_info *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;
@@ -156,12 +217,10 @@ struct git_graph *graph_init(struct rev_info *opt)
        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)
@@ -207,18 +266,58 @@ static int graph_is_interesting(struct git_graph *graph, struct commit *commit)
        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(graph, commit))
-               return;
-
        /*
         * If the commit is already in the new_columns list, we don't need to
         * add it.  Just update the mapping correctly.
@@ -342,9 +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);
@@ -389,11 +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(graph, 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.
@@ -404,21 +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;
@@ -497,10 +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,
@@ -535,7 +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, "| ");
@@ -550,7 +680,7 @@ 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);
 }
 
 static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
@@ -578,27 +708,13 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
                return;
        }
 
-       /*
-        * Print 'M' for merge commits
-        *
-        * Note that we don't check graph->num_parents to determine if the
-        * commit is a merge, since that only tracks the number of
-        * "interesting" parents.  We want to print 'M' for merge commits
-        * even if they have less than 2 interesting parents.
-        */
-       if (graph->commit->parents != NULL &&
-           graph->commit->parents->next != NULL) {
-               strbuf_addch(sb, 'M');
-               return;
-       }
-
        /*
         * Print '*' in all other cases
         */
        strbuf_addch(sb, '*');
 }
 
-void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
+static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 {
        int seen_this = 0;
        int i, j;
@@ -625,10 +741,8 @@ void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
                        seen_this = 1;
                        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;
@@ -636,8 +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, "| ");
                }
@@ -649,14 +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;
@@ -679,9 +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, "| ");
@@ -694,12 +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;
@@ -801,10 +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:
@@ -831,7 +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;
 
@@ -865,6 +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)
@@ -948,7 +1084,7 @@ 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;