From 1eb4136ac2a24764257567b930535fcece01719f Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 11 Feb 2021 11:57:50 -0800 Subject: diff: --{rotate,skip}-to= In the implementation of "git difftool", there is a case where the user wants to start viewing the diffs at a specific path and continue on to the rest, optionally wrapping around to the beginning. Since it is somewhat cumbersome to implement such a feature as a post-processing step of "git diff" output, let's support it internally with two new options. - "git diff --rotate-to=C", when the resulting patch would show paths A B C D E without the option, would "rotate" the paths to shows patch to C D E A B instead. It is an error when there is no patch for C is shown. - "git diff --skip-to=C" would instead "skip" the paths before C, and shows patch to C D E. Again, it is an error when there is no patch for C is shown. - "git log [-p]" also accepts these two options, but it is not an error if there is no change to the specified path. Instead, the set of output paths are rotated or skipped to the specified path or the first path that sorts after the specified path. Signed-off-by: Junio C Hamano --- diffcore-rotate.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 diffcore-rotate.c (limited to 'diffcore-rotate.c') diff --git a/diffcore-rotate.c b/diffcore-rotate.c new file mode 100644 index 0000000000..445f060ab0 --- /dev/null +++ b/diffcore-rotate.c @@ -0,0 +1,46 @@ +/* + * Copyright (C) 2021, Google LLC. + * Based on diffcore-order.c, which is Copyright (C) 2005, Junio C Hamano + */ +#include "cache.h" +#include "diff.h" +#include "diffcore.h" + +void diffcore_rotate(struct diff_options *opt) +{ + struct diff_queue_struct *q = &diff_queued_diff; + struct diff_queue_struct outq; + int rotate_to, i; + + if (!q->nr) + return; + + for (i = 0; i < q->nr; i++) { + int cmp = strcmp(opt->rotate_to, q->queue[i]->two->path); + if (!cmp) + break; /* exact match */ + if (!opt->rotate_to_strict && cmp < 0) + break; /* q->queue[i] is now past the target pathname */ + } + + if (q->nr <= i) { + /* we did not find the specified path */ + if (opt->rotate_to_strict) + die(_("No such path '%s' in the diff"), opt->rotate_to); + return; + } + + DIFF_QUEUE_CLEAR(&outq); + rotate_to = i; + + for (i = rotate_to; i < q->nr; i++) + diff_q(&outq, q->queue[i]); + for (i = 0; i < rotate_to; i++) { + if (opt->skip_instead_of_rotate) + diff_free_filepair(q->queue[i]); + else + diff_q(&outq, q->queue[i]); + } + free(q->queue); + *q = outq; +} -- cgit v1.2.3