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Diffstat (limited to 'graph.h')
| -rw-r--r-- | graph.h | 265 |
1 files changed, 265 insertions, 0 deletions
@@ -0,0 +1,265 @@ +#ifndef GRAPH_H +#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; + +/* + * Called to setup global display of line_prefix diff option. + * + * Passed a diff_options structure which indicates the line_prefix and the + * file to output the prefix to. This is sort of a hack used so that the + * line_prefix will be honored by all flows which also honor "--graph" + * regardless of whether a graph has actually been setup. The normal graph + * flow will honor the exact diff_options passed, but a NULL graph will cause + * display of a line_prefix to stdout. + */ +void graph_setup_line_prefix(struct diff_options *diffopt); + +/* + * Set up a custom scheme for column colors. + * + * The default column color scheme inserts ANSI color escapes to colorize + * the graph. The various color escapes are stored in an array of strings + * where each entry corresponds to a color, except for the last entry, + * which denotes the escape for resetting the color back to the default. + * When generating the graph, strings from this array are inserted before + * and after the various column characters. + * + * This function allows you to enable a custom array of color escapes. + * The 'colors_max' argument is the index of the last "reset" entry. + * + * This functions must be called BEFORE graph_init() is called. + * + * NOTE: This function isn't used in Git outside graph.c but it is used + * by CGit (http://git.zx2c4.com/cgit/) to use HTML for colors. + */ +void graph_set_column_colors(const char **colors, unsigned short colors_max); + +/* + * Create a new struct git_graph. + */ +struct git_graph *graph_init(struct rev_info *opt); + +/* + * Free a struct git_graph. + */ +void graph_clear(struct git_graph *graph); + +/* + * Update a git_graph with a new commit. + * This will cause the graph to begin outputting lines for the new commit + * the next time graph_next_line() is called. + * + * 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); + +/* + * Determine if a graph has finished outputting lines for the current + * commit. + * + * Returns 1 if graph_next_line() needs to be called again before + * graph_update() should be called. Returns 0 if no more lines are needed + * 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); + +/* + * 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. + * + * NOTE: This function isn't used in Git outside graph.c but it is used + * by CGit (http://git.zx2c4.com/cgit/) to wrap HTML around graph lines. + */ +int graph_next_line(struct git_graph *graph, struct strbuf *sb); + + +/* + * Return current width of the graph in on-screen characters. + */ +int graph_width(struct git_graph *graph); + +/* + * graph_show_*: helper functions for printing to stdout + */ + + +/* + * If the graph is non-NULL, print the history graph to stdout, + * up to and including the line containing this commit. + * Does not print a terminating newline on the last line. + */ +void graph_show_commit(struct git_graph *graph); + +/* + * If the graph is non-NULL, print one line of the history graph to stdout. + * Does not print a terminating newline on the last line. + */ +void graph_show_oneline(struct git_graph *graph); + +/* + * If the graph is non-NULL, print one line of vertical graph padding to + * stdout. Does not print a terminating newline on the last line. + */ +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); + +/* + * Print a commit message strbuf and the remainder of the graph to stdout. + * + * 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 + * printed by graph_show_commit_msg() will also be missing a terminating + * newline. + * + * Note that unlike some other graph display functions, you must pass the file + * handle directly. It is assumed that this is the same file handle as the + * file specified by the graph diff options. This is necessary so that + * graph_show_commit_msg can be called even with a NULL graph. + */ +void graph_show_commit_msg(struct git_graph *graph, + FILE *file, + struct strbuf const *sb); + +#endif /* GRAPH_H */ |