diff options
Diffstat (limited to 'graph.h')
| -rw-r--r-- | graph.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/graph.h b/graph.h index af623390b605..8313e293c78d 100644 --- a/graph.h +++ b/graph.h @@ -2,6 +2,103 @@ #define GRAPH_H #include "diff.h" +/** + * The graph API is used to draw a text-based representation of the commit + * history. The API generates the graph in a line-by-line fashion. + * + * Calling sequence + * ---------------- + * + * - Create a `struct git_graph` by calling `graph_init()`. When using the + * revision walking API, this is done automatically by `setup_revisions()` if + * the '--graph' option is supplied. + * + * - Use the revision walking API to walk through a group of contiguous commits. + * The `get_revision()` function automatically calls `graph_update()` each time + * it is invoked. + * + * - For each commit, call `graph_next_line()` repeatedly, until + * `graph_is_commit_finished()` returns non-zero. Each call to + * `graph_next_line()` will output a single line of the graph. The resulting + * lines will not contain any newlines. `graph_next_line()` returns 1 if the + * resulting line contains the current commit, or 0 if this is merely a line + * needed to adjust the graph before or after the current commit. This return + * value can be used to determine where to print the commit summary information + * alongside the graph output. + * + * Limitations + * ----------- + * - Check the graph_update() function for its limitations. + * + * - The graph API does not currently support reverse commit ordering. In + * order to implement reverse ordering, the graphing API needs an + * (efficient) mechanism to find the children of a commit. + * + * Sample usage + * ------------ + * + * ------------ + * struct commit *commit; + * struct git_graph *graph = graph_init(opts); + * + * while ((commit = get_revision(opts)) != NULL) { + * while (!graph_is_commit_finished(graph)) + * { + * struct strbuf sb; + * int is_commit_line; + * + * strbuf_init(&sb, 0); + * is_commit_line = graph_next_line(graph, &sb); + * fputs(sb.buf, stdout); + * + * if (is_commit_line) + * log_tree_commit(opts, commit); + * else + * putchar(opts->diffopt.line_termination); + * } + * } + * ------------ + * Sample output + * ------------- + * + * The following is an example of the output from the graph API. This output does + * not include any commit summary information--callers are responsible for + * outputting that information, if desired. + * ------------ + * * + * * + * * + * |\ + * * | + * | | * + * | \ \ + * | \ \ + * *-. \ \ + * |\ \ \ \ + * | | * | | + * | | | | | * + * | | | | | * + * | | | | | * + * | | | | | |\ + * | | | | | | * + * | * | | | | | + * | | | | | * \ + * | | | | | |\ | + * | | | | * | | | + * | | | | * | | | + * * | | | | | | | + * | |/ / / / / / + * |/| / / / / / + * * | | | | | | + * |/ / / / / / + * * | | | | | + * | | | | | * + * | | | | |/ + * | | | | * + * ------------ + * + */ + /* A graph is a pointer to this opaque structure */ struct git_graph; @@ -50,6 +147,21 @@ struct git_graph *graph_init(struct rev_info *opt); * If graph_update() is called before graph_is_commit_finished() returns 1, * the next call to graph_next_line() will output an ellipsis ("...") * to indicate that a portion of the graph is missing. + * + * Limitations: + * ----------- + * + * - `graph_update()` must be called with commits in topological order. It should + * not be called on a commit if it has already been invoked with an ancestor of + * that commit, or the graph output will be incorrect. + * + * - `graph_update()` must be called on a contiguous group of commits. If + * `graph_update()` is called on a particular commit, it should later be called + * on all parents of that commit. Parents must not be skipped, or the graph + * output will appear incorrect. + * + * - `graph_update()` may be used on a pruned set of commits only if the parent list + * has been rewritten so as to include only ancestors from the pruned set. */ void graph_update(struct git_graph *graph, struct commit *commit); @@ -62,6 +174,10 @@ void graph_update(struct git_graph *graph, struct commit *commit); * for this commit. If 0 is returned, graph_next_line() may still be * called without calling graph_update(), and it will merely output * appropriate "vertical padding" in the graph. + * + * If `graph_update()` is called before all lines for the current commit have + * been printed, the next call to `graph_next_line()` will output an ellipsis, + * to indicate that a portion of the graph was omitted. */ int graph_is_commit_finished(struct git_graph const *graph); @@ -112,6 +228,7 @@ void graph_show_padding(struct git_graph *graph); /* * If the graph is non-NULL, print the rest of the history graph for this * commit to stdout. Does not print a terminating newline on the last line. + * Returns 1 if output was printed, and 0 if no output was necessary. */ int graph_show_remainder(struct git_graph *graph); @@ -121,6 +238,10 @@ int graph_show_remainder(struct git_graph *graph); * This is similar to graph_show_strbuf(), but it always prints the * remainder of the graph. * + * It is better than directly calling `graph_show_strbuf()` followed by + * `graph_show_remainder()` since it properly handles buffers that do not end in + * a terminating newline. + * * If the strbuf ends with a newline, the output printed by * graph_show_commit_msg() will end with a newline. If the strbuf is * missing a terminating newline (including if it is empty), the output |