[PATCH v2 3/8] xdiff: handle appended chunks better with -W
- From
René Scharfe <l.s.r@web.de>
- Date
- May 28, 2016, 15:00 UTC
- Message-ID
- <5749B28C.5010006@web.de>
- In-Reply-To
- <5749AF59.2070704@web.de>
If lines are added at the end of a file, diff -W shows the whole file. That's because get_func_line() only considers the pre-image and gives up if it sees a record index beyond its end.
Consider the post-image as well to see if the added lines already make up a full function. If it doesn't then search for the previous function line by starting from the bottom of the pre-image, thereby avoiding to confuse get_func_line().
Reuse the existing label called "again", as it's exactly where we need to jump to when we're done handling the pre-context, but rename it to "post_context_calculation" in order to document its new purpose better.
Reported-by: Junio C Hamano <gitster@pobox.com> Initial-patch-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> --- t/t4051-diff-function-context.sh | 2 +- xdiff/xemit.c | 27 ++++++++++++++++++++++++--- 2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/t/t4051-diff-function-context.sh b/t/t4051-diff-function-context.sh index a3adba4..d78461d 100755 --- a/t/t4051-diff-function-context.sh +++ b/t/t4051-diff-function-context.sh @@ -131,7 +131,7 @@ test_expect_success ' context includes end' ' grep "^[+].*End of second part" extended.diff ' -test_expect_failure ' context does not include other functions' ' +test_expect_success ' context does not include other functions' ' test $(grep -c "^[ +-].*Begin" extended.diff) -le 2 ' diff --git a/xdiff/xemit.c b/xdiff/xemit.c index 0c87637..969100d 100644 --- a/xdiff/xemit.c +++ b/xdiff/xemit.c @@ -171,7 +171,28 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0); if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) { - long fs1 = get_func_line(xe, xecfg, NULL, xch->i1, -1); + long fs1, i1 = xch->i1; + + /* Appended chunk? */ + if (i1 >= xe->xdf1.nrec) { + char dummy[1]; + + /* + * We don't need additional context if + * a whole function was added. + */ + if (match_func_rec(&xe->xdf2, xecfg, xch->i2, + dummy, sizeof(dummy)) >= 0) + goto post_context_calculation; + + /* + * Otherwise get more context from the + * pre-image. + */ + i1 = xe->xdf1.nrec - 1; + } + + fs1 = get_func_line(xe, xecfg, NULL, i1, -1); if (fs1 < 0) fs1 = 0; if (fs1 < s1) { @@ -180,7 +201,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, } } - again: + post_context_calculation: lctx = xecfg->ctxlen; lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1)); lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2)); @@ -209,7 +230,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb, if (l <= e1 || get_func_line(xe, xecfg, NULL, l, e1) < 0) { xche = xche->next; - goto again; + goto post_context_calculation; } } }
-- 2.8.3