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Diffstat (limited to 'Documentation/technical')
| -rw-r--r-- | Documentation/technical/api-history-graph.txt | 173 |
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diff --git a/Documentation/technical/api-history-graph.txt b/Documentation/technical/api-history-graph.txt deleted file mode 100644 index d0d1707c8c..0000000000 --- a/Documentation/technical/api-history-graph.txt +++ /dev/null @@ -1,173 +0,0 @@ -history graph API -================= - -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. - -Functions ---------- - -Core functions: - -* `graph_init()` creates a new `struct git_graph` - -* `graph_update()` moves the graph to a new commit. - -* `graph_next_line()` outputs the next line of the graph into a strbuf. It - does not add a terminating newline. - -* `graph_padding_line()` outputs a line of vertical padding in the graph. It - is similar to `graph_next_line()`, but is guaranteed to never print the line - containing the current commit. Where `graph_next_line()` would print the - commit line next, `graph_padding_line()` prints a line that simply extends - all branch lines downwards one row, leaving their positions unchanged. - -* `graph_is_commit_finished()` determines if the graph has output all lines - necessary for the current commit. 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. - -The following utility functions are wrappers around `graph_next_line()` and -`graph_is_commit_finished()`. They always print the output to stdout. -They can all be called with a NULL graph argument, in which case no graph -output will be printed. - -* `graph_show_commit()` calls `graph_next_line()` and - `graph_is_commit_finished()` until one of them return non-zero. This prints - all graph lines up to, and including, the line containing this commit. - Output is printed to stdout. The last line printed does not contain a - terminating newline. - -* `graph_show_oneline()` calls `graph_next_line()` and prints the result to - stdout. The line printed does not contain a terminating newline. - -* `graph_show_padding()` calls `graph_padding_line()` and prints the result to - stdout. The line printed does not contain a terminating newline. - -* `graph_show_remainder()` calls `graph_next_line()` until - `graph_is_commit_finished()` returns non-zero. Output is printed to stdout. - The last line printed does not contain a terminating newline. Returns 1 if - output was printed, and 0 if no output was necessary. - -* `graph_show_strbuf()` prints the specified strbuf to stdout, prefixing all - lines but the first with a graph line. The caller is responsible for - ensuring graph output for the first line has already been printed to stdout. - (This can be done with `graph_show_commit()` or `graph_show_oneline()`.) If - a NULL graph is supplied, the strbuf is printed as-is. - -* `graph_show_commit_msg()` is similar to `graph_show_strbuf()`, but it also - prints the remainder of the graph, if more lines are needed after the strbuf - ends. 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. The output printed by `graph_show_commit_msg()` will - end in a newline if and only if the strbuf ends in a newline. - -Data structure --------------- -`struct git_graph` is an opaque data type used to store the current graph -state. - -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 ------------ - -* `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. - -* 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. - ------------- -* -* -* -|\ -* | -| | * -| \ \ -| \ \ -*-. \ \ -|\ \ \ \ -| | * | | -| | | | | * -| | | | | * -| | | | | * -| | | | | |\ -| | | | | | * -| * | | | | | -| | | | | * \ -| | | | | |\ | -| | | | * | | | -| | | | * | | | -* | | | | | | | -| |/ / / / / / -|/| / / / / / -* | | | | | | -|/ / / / / / -* | | | | | -| | | | | * -| | | | |/ -| | | | * ------------- |