From: Zbigniew Jędrzejewski-Szmek Date: Thu, 12 Apr 2012 10:17:11 GMT Subject: Re: [PATCH v2 2/3] Adjust stat width calculations to take --graph output into account Message-ID: <4F86ABA7.8080703@in.waw.pl> In-Reply-To: On 04/12/2012 09:47 AM, Lucian Poston wrote: > On Fri, Mar 23, 2012 at 03:12, Zbigniew Jędrzejewski-Szmek > wrote: >> On 03/23/2012 06:54 AM, Lucian Poston wrote: >> >>> diff --git a/diff.c b/diff.c >>> index 377ec1e..31ba10c 100644 >>> --- a/diff.c >>> +++ b/diff.c >>> @@ -1383,6 +1383,8 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options) >>> int width, name_width, graph_width, number_width = 4, count; >>> const char *reset, *add_c, *del_c; >>> const char *line_prefix = ""; >>> + int line_prefix_length = 0; >>> + int reserved_character_count; >>> int extra_shown = 0; >>> struct strbuf *msg = NULL; >>> >>> @@ -1392,6 +1394,7 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options) >>> if (options->output_prefix) { >>> msg = options->output_prefix(options, options->output_prefix_data); >>> line_prefix = msg->buf; >>> + line_prefix_length = options->output_prefix_length; >>> } >> Hi, >> line_prefix will only be used once. And options->output_prefix_length will >> be 0 if !options->output_prefix, so line_prefix variable can be eliminated >> and options->output_prefix_length used directly instead. > > Rather than adding the line_prefix_length variable, the next patch > will use options->output_prefix_length directly. > >>> count = options->stat_count ? options->stat_count : data->nr; >>> @@ -1427,37 +1430,46 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options) >>> * We have width = stat_width or term_columns() columns total. >>> * We want a maximum of min(max_len, stat_name_width) for the name part. >>> * We want a maximum of min(max_change, stat_graph_width) for the +- part. >>> - * We also need 1 for " " and 4 + decimal_width(max_change) >>> - * for " | NNNN " and one the empty column at the end, altogether >>> + * Each line needs space for the following characters: >>> + * - 1 for the initial " " >>> + * - 4 + decimal_width(max_change) for " | NNNN " >>> + * - 1 for the empty column at the end, >>> + * Altogether, the reserved_character_count totals >>> * 6 + decimal_width(max_change). >>> * >>> - * If there's not enough space, we will use the smaller of >>> - * stat_name_width (if set) and 5/8*width for the filename, >>> - * and the rest for constant elements + graph part, but no more >>> - * than stat_graph_width for the graph part. >>> - * (5/8 gives 50 for filename and 30 for the constant parts + graph >>> - * for the standard terminal size). >>> + * Additionally, there may be a line_prefix, which reduces the available >>> + * width by line_prefix_length. >>> + * >>> + * If there's not enough space, we will use the smaller of stat_name_width >>> + * (if set) and 5/8*width for the filename, and the rest for the graph >>> + * part, but no more than stat_graph_width for the graph part. >>> + * Assuming the line prefix is empty, on a standard 80 column terminal >>> + * this ratio results in 50 characters for the filename and 20 characters >>> + * for the graph (plus the 10 reserved characters). >>> * >>> * In other words: stat_width limits the maximum width, and >>> * stat_name_width fixes the maximum width of the filename, >>> * and is also used to divide available columns if there >>> * aren't enough. >>> */ >>> + reserved_character_count = 6 + number_width; >>> >>> if (options->stat_width == -1) >>> width = term_columns(); >>> else >>> width = options->stat_width ? options->stat_width : 80; >>> >>> + width -= line_prefix_length; >>> + >>> if (options->stat_graph_width == -1) >>> options->stat_graph_width = diff_stat_graph_width; >>> >>> /* >>> - * Guarantee 3/8*16==6 for the graph part >>> - * and 5/8*16==10 for the filename part >>> + * Guarantees at least 6 characters for the graph part [16 * 3/8] >>> + * and at least 10 for the filename part [16 * 5/8] >>> */ >>> - if (width< 16 + 6 + number_width) >>> - width = 16 + 6 + number_width; >>> + if (width< 16 + reserved_character_count) >>> + width = 16 + reserved_character_count; >>> >>> /* >>> * First assign sizes that are wanted, ignoring available width. >>> @@ -1472,16 +1484,36 @@ static void show_stats(struct diffstat_t *data, struct diff_options *options) >>> /* >>> * Adjust adjustable widths not to exceed maximum width >>> */ >> >> In this part below, you add gratuitous braces around single line if-blocks. >> This makes the code (and the diff) longer with no gain. > > I prefer gratuitous braces, particularly when conditionals are nested > as they are here. It helps later when maintaining the code if someone > wants to add a debug statement or comment out a line. > > I'll remove braces from single line conditionals to keep with the > existing conventions. Thanks. >>> - if (name_width + number_width + 6 + graph_width> width) { >>> - if (graph_width> width * 3/8 - number_width - 6) >>> - graph_width = width * 3/8 - number_width - 6; >>> + if (reserved_character_count + name_width + graph_width> width) { >>> + /* >>> + * Reduce graph_width to be at most 3/8 of the unreserved space and no >>> + * less than 6, which leaves at least 5/8 for the filename. >>> + */ >>> + if (graph_width> width * 3/8 - reserved_character_count) { >>> + graph_width = width * 3/8 - reserved_character_count; >>> + if (graph_width< 6) { >>> + graph_width = 6; >>> + } >>> + } >> This extra test is not necessary. Above, after /* Guarantees at least 6 characters >> for the graph part [16 * 3/8] ... */, this should already by so that >> (width * 3/8 - reserved_character_count) is at least 6. > > Ahh, this is because the calculations go haywire when the number of > columns is small. I briefly mentioned it here: > http://thread.gmane.org/gmane.comp.version-control.git/193694/focus=193744 > > graph_width actually can have a negative value under certain > conditions, and this check compensates for that edge case. My earlier > patches took a less conservative approach and adjusted the > calculations so that the value of graph_width would be at least 6, but > it caused several tests to regress. Since the intention of the > original graph_width calculation was place a lower bound of 6 on its > value, I simply enforce that here without affecting the general cases, > which will remain unmodified in order to prevent test regressions. > >>> + >>> + /* >>> + * If the remaining unreserved space will not accomodate the >>> + * filenames, adjust name_width to use all available remaining space. >>> + * Otherwise, assign any extra space to graph_width. >>> + */ >>> + if (name_width> width - reserved_character_count - graph_width) { >>> + name_width = width - reserved_character_count - graph_width; >>> + } else { >>> + graph_width = width - reserved_character_count - name_width; >>> + } >>> + >>> + /* >>> + * If stat-graph-width was specified, limit graph_width to its value. >>> + */ >>> if (options->stat_graph_width&& >>> - graph_width> options->stat_graph_width) >>> + graph_width> options->stat_graph_width) { >>> graph_width = options->stat_graph_width; >>> - if (name_width> width - number_width - 6 - graph_width) >>> - name_width = width - number_width - 6 - graph_width; >>> - else >>> - graph_width = width - number_width - 6 - name_width; >>> + } >> Here, the order of the two tests >> (1) if (options->stat_graph_width&& graph_width> options->stat_graph_width) >> (2) if (name_width> width - number_width - 6 - graph_width) >> is reversed. This is not OK, because this means that >> options->stat_graph_width will be used unconditionally, while >> before it was subject to limiting by total width. > > If options->stat_graph_width is specified, it should always limit the > value of graph_width, correct? Since (1) is the last test, it can only > decrease the value of graph_width, which would already be limited by > the total width. Right, but the way the tests are ordered now, we could end up decreasing name_width first (after (2)) and then graph_width (after (1)), actually using less than full width. > I just noticed that name_width isn't being limited to stat_name_width, > if it is specified. I'll add a check for that. Sounds good. >> The tests: >> After the new tests are added, I see: >> >> ok 53 - format-patch ignores COLUMNS (long filename) >> ok 54 - diff respects COLUMNS (long filename) >> ok 55 - show respects COLUMNS (long filename) >> ok 56 - log respects COLUMNS (long filename) >> ok 57 - show respects 80 COLUMNS (long filename)<======= >> ok 58 - log respects 80 COLUMNS (long filename)<------- >> ok 59 - show respects 80 COLUMNS (long filename)<======= >> ok 60 - log respects 80 COLUMNS (long filename)<------- >> >> So some tests descriptions are duplicated. Also it would be >> nice to test with --graph in more places. I'm attaching a >> replacement patch which adds more tests. It should go *before* >> your series, and your series should tweak the tests to pass, >> showing what changed. > > Thanks, I'll add these. Regards, Zbyszek