Jacob Keller <jacob.keller@xxxxxxxxx> writes:
> I think we're going to make use of xdl_blankline instead of this or
> our own "is_emptyline"
OK, so perhaps either of you two can do a final version people can
start having fun with?
By the way, I really do not want to see something this low-level to
be end-user tweakable with "one bit enable/disable"; the end users
shouldn't have to bother [1]. I left it in but renamed after "what"
it enables/disables, not "how" the enabled thing works, to clarify
that we have this only as a developers' aid.
*1* I am fine with --compaction-heuristic=(shortest|blank|...) that
allows a choice among many as a developers' aid, but I do not think
this topic is there yet.
Documentation/diff-config.txt | 9 ++++-----
Documentation/diff-options.txt | 10 +++++-----
diff.c | 18 +++++++++---------
xdiff/xdiff.h | 2 +-
xdiff/xdiffi.c | 22 ++++++++++------------
5 files changed, 29 insertions(+), 32 deletions(-)
diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index c62745b..9bf3e92 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -166,11 +166,10 @@ diff.tool::
include::mergetools-diff.txt[]
-diff.shortestLineHeuristic::
- Set this option to true to enable the shortest line chunk heuristic when
- producing diff output. This heuristic will attempt to shift hunks such
- that the last shortest common line occurs below the hunk with the rest of
- the context above it.
+diff.compactionHeuristic::
+ Set this option to enable an experimental heuristic that
+ shifts the hunk boundary in an attempt to make the resulting
+ patch easier to read.
diff.algorithm::
Choose a diff algorithm. The variants are as follows:
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 238f39c..b513023 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -63,11 +63,11 @@ ifndef::git-format-patch[]
Synonym for `-p --raw`.
endif::git-format-patch[]
---shortest-line-heuristic::
---no-shortest-line-heuristic::
- When possible, shift common shortest line in diff hunks below the hunk
- such that the last common shortest line for each hunk is below, with the
- rest of the context above the hunk.
+--compaction-heuristic::
+--no-compaction-heuristic::
+ These are to help debugging and tuning an experimental
+ heuristic that shifts the hunk boundary in an attempt to
+ make the resulting patch easier to read.
--minimal::
Spend extra time to make sure the smallest possible
diff --git a/diff.c b/diff.c
index 276174c..02c75c3 100644
--- a/diff.c
+++ b/diff.c
@@ -25,7 +25,7 @@
#endif
static int diff_detect_rename_default;
-static int diff_shortest_line_heuristic = 0;
+static int diff_compaction_heuristic = 1;
static int diff_rename_limit_default = 400;
static int diff_suppress_blank_empty;
static int diff_use_color_default = -1;
@@ -184,8 +184,8 @@ int git_diff_ui_config(const char *var, const char *value, void *cb)
diff_detect_rename_default = git_config_rename(var, value);
return 0;
}
- if (!strcmp(var, "diff.shortestlineheuristic")) {
- diff_shortest_line_heuristic = git_config_bool(var, value);
+ if (!strcmp(var, "diff.compactionheuristic")) {
+ diff_compaction_heuristic = git_config_bool(var, value);
return 0;
}
if (!strcmp(var, "diff.autorefreshindex")) {
@@ -3240,8 +3240,8 @@ void diff_setup(struct diff_options *options)
options->use_color = diff_use_color_default;
options->detect_rename = diff_detect_rename_default;
options->xdl_opts |= diff_algorithm;
- if (diff_shortest_line_heuristic)
- DIFF_XDL_SET(options, SHORTEST_LINE_HEURISTIC);
+ if (diff_compaction_heuristic)
+ DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
options->orderfile = diff_order_file_cfg;
@@ -3719,10 +3719,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
else if (!strcmp(arg, "--ignore-blank-lines"))
DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
- else if (!strcmp(arg, "--shortest-line-heuristic"))
- DIFF_XDL_SET(options, SHORTEST_LINE_HEURISTIC);
- else if (!strcmp(arg, "--no-shortest-line-heuristic"))
- DIFF_XDL_CLR(options, SHORTEST_LINE_HEURISTIC);
+ else if (!strcmp(arg, "--compaction-heuristic"))
+ DIFF_XDL_SET(options, COMPACTION_HEURISTIC);
+ else if (!strcmp(arg, "--no-compaction-heuristic"))
+ DIFF_XDL_CLR(options, COMPACTION_HEURISTIC);
else if (!strcmp(arg, "--patience"))
options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
else if (!strcmp(arg, "--histogram"))
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 968ac62..d1dbb27 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -41,7 +41,7 @@ extern "C" {
#define XDF_IGNORE_BLANK_LINES (1 << 7)
-#define XDF_SHORTEST_LINE_HEURISTIC (1 << 8)
+#define XDF_COMPACTION_HEURISTIC (1 << 8)
#define XDL_EMIT_FUNCNAMES (1 << 0)
#define XDL_EMIT_COMMON (1 << 1)
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index 7d15b26..1ec46e0 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -400,10 +400,9 @@ static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1,
}
-static int line_length(const char *recs)
+static int is_blank_line(xrecord_t **recs, long ix, long flags)
{
- char *s = strchr(recs, '\n');
- return s ? s - recs : strlen(recs);
+ return xdl_blankline(recs[ix]->ptr, recs[ix]->size, flags);
}
static int recs_match(xrecord_t **recs, long ixs, long ix, long flags)
@@ -417,7 +416,7 @@ static int recs_match(xrecord_t **recs, long ixs, long ix, long flags)
int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
long ix, ixo, ixs, ixref, grpsiz, nrec = xdf->nrec;
char *rchg = xdf->rchg, *rchgo = xdfo->rchg;
- unsigned int shortest_line;
+ unsigned int blank_lines;
xrecord_t **recs = xdf->recs;
/*
@@ -451,7 +450,7 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
do {
grpsiz = ix - ixs;
- shortest_line = UINT_MAX;
+ blank_lines = 0;
/*
* If the line before the current change group, is equal to
@@ -486,9 +485,8 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
* the group.
*/
while (ix < nrec && recs_match(recs, ixs, ix, flags)) {
- int l = line_length(recs[ix]->ptr);
- if (l < shortest_line)
- shortest_line = l;
+
+ blank_lines += is_blank_line(recs, ix, flags);
rchg[ixs++] = 0;
rchg[ix++] = 1;
@@ -519,15 +517,15 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
/*
* If a group can be moved back and forth, see if there is an
- * empty line in the moving space. If there is an empty line,
- * make sure the last empty line is the end of the group.
+ * blank line in the moving space. If there is a blank line,
+ * make sure the last blank line is the end of the group.
*
* As we shifted the group forward as far as possible, we only
* need to shift it back if at all.
*/
- if ((flags & XDF_SHORTEST_LINE_HEURISTIC)) {
+ if ((flags & XDF_COMPACTION_HEURISTIC)) {
while (ixs > 0 &&
- line_length(recs[ix - 1]->ptr) > shortest_line &&
+ !is_blank_line(recs, ix - 1, flags) &&
recs_match(recs, ixs - 1, ix - 1, flags)) {
rchg[--ixs] = 1;
rchg[--ix] = 0;
--
2.8.1-399-g96b3b3a
--
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