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authorJunio C Hamano <gitster@pobox.com>2009-01-24 05:51:38 (GMT)
committerJunio C Hamano <gitster@pobox.com>2009-01-24 05:51:38 (GMT)
commit5dc1308562ab5991ecada68b06707709bea408c9 (patch)
tree321b8d7310c01d8b01584377d9aba448952a7384
parentf3d6073e02f8ee8dc6376b0262151dbbfbbdfe7d (diff)
parentcc545709253fe8440db2648cb5c771e5b126bdb5 (diff)
downloadgit-5dc1308562ab5991ecada68b06707709bea408c9.zip
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Merge branch 'js/patience-diff'
* js/patience-diff: bash completions: Add the --patience option Introduce the diff option '--patience' Implement the patience diff algorithm Conflicts: contrib/completion/git-completion.bash
-rw-r--r--Documentation/diff-options.txt3
-rw-r--r--Makefile2
-rwxr-xr-xcontrib/completion/git-completion.bash1
-rw-r--r--diff.c2
-rwxr-xr-xt/t4033-diff-patience.sh168
-rw-r--r--xdiff/xdiff.h1
-rw-r--r--xdiff/xdiffi.c3
-rw-r--r--xdiff/xdiffi.h2
-rw-r--r--xdiff/xpatience.c381
-rw-r--r--xdiff/xprepare.c3
10 files changed, 564 insertions, 2 deletions
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 43793d7..1f8ce97 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -36,6 +36,9 @@ endif::git-format-patch[]
--patch-with-raw::
Synonym for "-p --raw".
+--patience:
+ Generate a diff using the "patience diff" algorithm.
+
--stat[=width[,name-width]]::
Generate a diffstat. You can override the default
output width for 80-column terminal by "--stat=width".
diff --git a/Makefile b/Makefile
index 270b223..b4d9cb4 100644
--- a/Makefile
+++ b/Makefile
@@ -1287,7 +1287,7 @@ $(LIB_FILE): $(LIB_OBJS)
$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIB_OBJS)
XDIFF_OBJS=xdiff/xdiffi.o xdiff/xprepare.o xdiff/xutils.o xdiff/xemit.o \
- xdiff/xmerge.o
+ xdiff/xmerge.o xdiff/xpatience.o
$(XDIFF_OBJS): xdiff/xinclude.h xdiff/xmacros.h xdiff/xdiff.h xdiff/xtypes.h \
xdiff/xutils.h xdiff/xprepare.h xdiff/xdiffi.h xdiff/xemit.h
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 703f4c2..81f70ec 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -783,6 +783,7 @@ __git_diff_common_options="--stat --numstat --shortstat --summary
--no-ext-diff
--no-prefix --src-prefix= --dst-prefix=
--inter-hunk-context=
+ --patience
--raw
"
diff --git a/diff.c b/diff.c
index 0731313..82cff97 100644
--- a/diff.c
+++ b/diff.c
@@ -2474,6 +2474,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
else if (!strcmp(arg, "--ignore-space-at-eol"))
options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
+ else if (!strcmp(arg, "--patience"))
+ options->xdl_opts |= XDF_PATIENCE_DIFF;
/* flags options */
else if (!strcmp(arg, "--binary")) {
diff --git a/t/t4033-diff-patience.sh b/t/t4033-diff-patience.sh
new file mode 100755
index 0000000..1eb1498
--- /dev/null
+++ b/t/t4033-diff-patience.sh
@@ -0,0 +1,168 @@
+#!/bin/sh
+
+test_description='patience diff algorithm'
+
+. ./test-lib.sh
+
+cat >file1 <<\EOF
+#include <stdio.h>
+
+// Frobs foo heartily
+int frobnitz(int foo)
+{
+ int i;
+ for(i = 0; i < 10; i++)
+ {
+ printf("Your answer is: ");
+ printf("%d\n", foo);
+ }
+}
+
+int fact(int n)
+{
+ if(n > 1)
+ {
+ return fact(n-1) * n;
+ }
+ return 1;
+}
+
+int main(int argc, char **argv)
+{
+ frobnitz(fact(10));
+}
+EOF
+
+cat >file2 <<\EOF
+#include <stdio.h>
+
+int fib(int n)
+{
+ if(n > 2)
+ {
+ return fib(n-1) + fib(n-2);
+ }
+ return 1;
+}
+
+// Frobs foo heartily
+int frobnitz(int foo)
+{
+ int i;
+ for(i = 0; i < 10; i++)
+ {
+ printf("%d\n", foo);
+ }
+}
+
+int main(int argc, char **argv)
+{
+ frobnitz(fib(10));
+}
+EOF
+
+cat >expect <<\EOF
+diff --git a/file1 b/file2
+index 6faa5a3..e3af329 100644
+--- a/file1
++++ b/file2
+@@ -1,26 +1,25 @@
+ #include <stdio.h>
+
++int fib(int n)
++{
++ if(n > 2)
++ {
++ return fib(n-1) + fib(n-2);
++ }
++ return 1;
++}
++
+ // Frobs foo heartily
+ int frobnitz(int foo)
+ {
+ int i;
+ for(i = 0; i < 10; i++)
+ {
+- printf("Your answer is: ");
+ printf("%d\n", foo);
+ }
+ }
+
+-int fact(int n)
+-{
+- if(n > 1)
+- {
+- return fact(n-1) * n;
+- }
+- return 1;
+-}
+-
+ int main(int argc, char **argv)
+ {
+- frobnitz(fact(10));
++ frobnitz(fib(10));
+ }
+EOF
+
+test_expect_success 'patience diff' '
+
+ test_must_fail git diff --no-index --patience file1 file2 > output &&
+ test_cmp expect output
+
+'
+
+test_expect_success 'patience diff output is valid' '
+
+ mv file2 expect &&
+ git apply < output &&
+ test_cmp expect file2
+
+'
+
+cat >uniq1 <<\EOF
+1
+2
+3
+4
+5
+6
+EOF
+
+cat >uniq2 <<\EOF
+a
+b
+c
+d
+e
+f
+EOF
+
+cat >expect <<\EOF
+diff --git a/uniq1 b/uniq2
+index b414108..0fdf397 100644
+--- a/uniq1
++++ b/uniq2
+@@ -1,6 +1,6 @@
+-1
+-2
+-3
+-4
+-5
+-6
++a
++b
++c
++d
++e
++f
+EOF
+
+test_expect_success 'completely different files' '
+
+ test_must_fail git diff --no-index --patience uniq1 uniq2 > output &&
+ test_cmp expect output
+
+'
+
+test_done
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 361f802..4da052a 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -32,6 +32,7 @@ extern "C" {
#define XDF_IGNORE_WHITESPACE (1 << 2)
#define XDF_IGNORE_WHITESPACE_CHANGE (1 << 3)
#define XDF_IGNORE_WHITESPACE_AT_EOL (1 << 4)
+#define XDF_PATIENCE_DIFF (1 << 5)
#define XDF_WHITESPACE_FLAGS (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE | XDF_IGNORE_WHITESPACE_AT_EOL)
#define XDL_PATCH_NORMAL '-'
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index 9d0324a..3e97462 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -329,6 +329,9 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
xdalgoenv_t xenv;
diffdata_t dd1, dd2;
+ if (xpp->flags & XDF_PATIENCE_DIFF)
+ return xdl_do_patience_diff(mf1, mf2, xpp, xe);
+
if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0) {
return -1;
diff --git a/xdiff/xdiffi.h b/xdiff/xdiffi.h
index 3e099dc..ad033a8 100644
--- a/xdiff/xdiffi.h
+++ b/xdiff/xdiffi.h
@@ -55,5 +55,7 @@ int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr);
void xdl_free_script(xdchange_t *xscr);
int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
xdemitconf_t const *xecfg);
+int xdl_do_patience_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+ xdfenv_t *env);
#endif /* #if !defined(XDIFFI_H) */
diff --git a/xdiff/xpatience.c b/xdiff/xpatience.c
new file mode 100644
index 0000000..e42c16a
--- /dev/null
+++ b/xdiff/xpatience.c
@@ -0,0 +1,381 @@
+/*
+ * LibXDiff by Davide Libenzi ( File Differential Library )
+ * Copyright (C) 2003-2009 Davide Libenzi, Johannes E. Schindelin
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+#include "xinclude.h"
+#include "xtypes.h"
+#include "xdiff.h"
+
+/*
+ * The basic idea of patience diff is to find lines that are unique in
+ * both files. These are intuitively the ones that we want to see as
+ * common lines.
+ *
+ * The maximal ordered sequence of such line pairs (where ordered means
+ * that the order in the sequence agrees with the order of the lines in
+ * both files) naturally defines an initial set of common lines.
+ *
+ * Now, the algorithm tries to extend the set of common lines by growing
+ * the line ranges where the files have identical lines.
+ *
+ * Between those common lines, the patience diff algorithm is applied
+ * recursively, until no unique line pairs can be found; these line ranges
+ * are handled by the well-known Myers algorithm.
+ */
+
+#define NON_UNIQUE ULONG_MAX
+
+/*
+ * This is a hash mapping from line hash to line numbers in the first and
+ * second file.
+ */
+struct hashmap {
+ int nr, alloc;
+ struct entry {
+ unsigned long hash;
+ /*
+ * 0 = unused entry, 1 = first line, 2 = second, etc.
+ * line2 is NON_UNIQUE if the line is not unique
+ * in either the first or the second file.
+ */
+ unsigned long line1, line2;
+ /*
+ * "next" & "previous" are used for the longest common
+ * sequence;
+ * initially, "next" reflects only the order in file1.
+ */
+ struct entry *next, *previous;
+ } *entries, *first, *last;
+ /* were common records found? */
+ unsigned long has_matches;
+ mmfile_t *file1, *file2;
+ xdfenv_t *env;
+ xpparam_t const *xpp;
+};
+
+/* The argument "pass" is 1 for the first file, 2 for the second. */
+static void insert_record(int line, struct hashmap *map, int pass)
+{
+ xrecord_t **records = pass == 1 ?
+ map->env->xdf1.recs : map->env->xdf2.recs;
+ xrecord_t *record = records[line - 1], *other;
+ /*
+ * After xdl_prepare_env() (or more precisely, due to
+ * xdl_classify_record()), the "ha" member of the records (AKA lines)
+ * is _not_ the hash anymore, but a linearized version of it. In
+ * other words, the "ha" member is guaranteed to start with 0 and
+ * the second record's ha can only be 0 or 1, etc.
+ *
+ * So we multiply ha by 2 in the hope that the hashing was
+ * "unique enough".
+ */
+ int index = (int)((record->ha << 1) % map->alloc);
+
+ while (map->entries[index].line1) {
+ other = map->env->xdf1.recs[map->entries[index].line1 - 1];
+ if (map->entries[index].hash != record->ha ||
+ !xdl_recmatch(record->ptr, record->size,
+ other->ptr, other->size,
+ map->xpp->flags)) {
+ if (++index >= map->alloc)
+ index = 0;
+ continue;
+ }
+ if (pass == 2)
+ map->has_matches = 1;
+ if (pass == 1 || map->entries[index].line2)
+ map->entries[index].line2 = NON_UNIQUE;
+ else
+ map->entries[index].line2 = line;
+ return;
+ }
+ if (pass == 2)
+ return;
+ map->entries[index].line1 = line;
+ map->entries[index].hash = record->ha;
+ if (!map->first)
+ map->first = map->entries + index;
+ if (map->last) {
+ map->last->next = map->entries + index;
+ map->entries[index].previous = map->last;
+ }
+ map->last = map->entries + index;
+ map->nr++;
+}
+
+/*
+ * This function has to be called for each recursion into the inter-hunk
+ * parts, as previously non-unique lines can become unique when being
+ * restricted to a smaller part of the files.
+ *
+ * It is assumed that env has been prepared using xdl_prepare().
+ */
+static int fill_hashmap(mmfile_t *file1, mmfile_t *file2,
+ xpparam_t const *xpp, xdfenv_t *env,
+ struct hashmap *result,
+ int line1, int count1, int line2, int count2)
+{
+ result->file1 = file1;
+ result->file2 = file2;
+ result->xpp = xpp;
+ result->env = env;
+
+ /* We know exactly how large we want the hash map */
+ result->alloc = count1 * 2;
+ result->entries = (struct entry *)
+ xdl_malloc(result->alloc * sizeof(struct entry));
+ if (!result->entries)
+ return -1;
+ memset(result->entries, 0, result->alloc * sizeof(struct entry));
+
+ /* First, fill with entries from the first file */
+ while (count1--)
+ insert_record(line1++, result, 1);
+
+ /* Then search for matches in the second file */
+ while (count2--)
+ insert_record(line2++, result, 2);
+
+ return 0;
+}
+
+/*
+ * Find the longest sequence with a smaller last element (meaning a smaller
+ * line2, as we construct the sequence with entries ordered by line1).
+ */
+static int binary_search(struct entry **sequence, int longest,
+ struct entry *entry)
+{
+ int left = -1, right = longest;
+
+ while (left + 1 < right) {
+ int middle = (left + right) / 2;
+ /* by construction, no two entries can be equal */
+ if (sequence[middle]->line2 > entry->line2)
+ right = middle;
+ else
+ left = middle;
+ }
+ /* return the index in "sequence", _not_ the sequence length */
+ return left;
+}
+
+/*
+ * The idea is to start with the list of common unique lines sorted by
+ * the order in file1. For each of these pairs, the longest (partial)
+ * sequence whose last element's line2 is smaller is determined.
+ *
+ * For efficiency, the sequences are kept in a list containing exactly one
+ * item per sequence length: the sequence with the smallest last
+ * element (in terms of line2).
+ */
+static struct entry *find_longest_common_sequence(struct hashmap *map)
+{
+ struct entry **sequence = xdl_malloc(map->nr * sizeof(struct entry *));
+ int longest = 0, i;
+ struct entry *entry;
+
+ for (entry = map->first; entry; entry = entry->next) {
+ if (!entry->line2 || entry->line2 == NON_UNIQUE)
+ continue;
+ i = binary_search(sequence, longest, entry);
+ entry->previous = i < 0 ? NULL : sequence[i];
+ sequence[++i] = entry;
+ if (i == longest)
+ longest++;
+ }
+
+ /* No common unique lines were found */
+ if (!longest) {
+ xdl_free(sequence);
+ return NULL;
+ }
+
+ /* Iterate starting at the last element, adjusting the "next" members */
+ entry = sequence[longest - 1];
+ entry->next = NULL;
+ while (entry->previous) {
+ entry->previous->next = entry;
+ entry = entry->previous;
+ }
+ xdl_free(sequence);
+ return entry;
+}
+
+static int match(struct hashmap *map, int line1, int line2)
+{
+ xrecord_t *record1 = map->env->xdf1.recs[line1 - 1];
+ xrecord_t *record2 = map->env->xdf2.recs[line2 - 1];
+ return xdl_recmatch(record1->ptr, record1->size,
+ record2->ptr, record2->size, map->xpp->flags);
+}
+
+static int patience_diff(mmfile_t *file1, mmfile_t *file2,
+ xpparam_t const *xpp, xdfenv_t *env,
+ int line1, int count1, int line2, int count2);
+
+static int walk_common_sequence(struct hashmap *map, struct entry *first,
+ int line1, int count1, int line2, int count2)
+{
+ int end1 = line1 + count1, end2 = line2 + count2;
+ int next1, next2;
+
+ for (;;) {
+ /* Try to grow the line ranges of common lines */
+ if (first) {
+ next1 = first->line1;
+ next2 = first->line2;
+ while (next1 > line1 && next2 > line2 &&
+ match(map, next1 - 1, next2 - 1)) {
+ next1--;
+ next2--;
+ }
+ } else {
+ next1 = end1;
+ next2 = end2;
+ }
+ while (line1 < next1 && line2 < next2 &&
+ match(map, line1, line2)) {
+ line1++;
+ line2++;
+ }
+
+ /* Recurse */
+ if (next1 > line1 || next2 > line2) {
+ struct hashmap submap;
+
+ memset(&submap, 0, sizeof(submap));
+ if (patience_diff(map->file1, map->file2,
+ map->xpp, map->env,
+ line1, next1 - line1,
+ line2, next2 - line2))
+ return -1;
+ }
+
+ if (!first)
+ return 0;
+
+ while (first->next &&
+ first->next->line1 == first->line1 + 1 &&
+ first->next->line2 == first->line2 + 1)
+ first = first->next;
+
+ line1 = first->line1 + 1;
+ line2 = first->line2 + 1;
+
+ first = first->next;
+ }
+}
+
+static int fall_back_to_classic_diff(struct hashmap *map,
+ int line1, int count1, int line2, int count2)
+{
+ /*
+ * This probably does not work outside Git, since
+ * we have a very simple mmfile structure.
+ *
+ * Note: ideally, we would reuse the prepared environment, but
+ * the libxdiff interface does not (yet) allow for diffing only
+ * ranges of lines instead of the whole files.
+ */
+ mmfile_t subfile1, subfile2;
+ xpparam_t xpp;
+ xdfenv_t env;
+
+ subfile1.ptr = (char *)map->env->xdf1.recs[line1 - 1]->ptr;
+ subfile1.size = map->env->xdf1.recs[line1 + count1 - 2]->ptr +
+ map->env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
+ subfile2.ptr = (char *)map->env->xdf2.recs[line2 - 1]->ptr;
+ subfile2.size = map->env->xdf2.recs[line2 + count2 - 2]->ptr +
+ map->env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
+ xpp.flags = map->xpp->flags & ~XDF_PATIENCE_DIFF;
+ if (xdl_do_diff(&subfile1, &subfile2, &xpp, &env) < 0)
+ return -1;
+
+ memcpy(map->env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
+ memcpy(map->env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
+
+ xdl_free_env(&env);
+
+ return 0;
+}
+
+/*
+ * Recursively find the longest common sequence of unique lines,
+ * and if none was found, ask xdl_do_diff() to do the job.
+ *
+ * This function assumes that env was prepared with xdl_prepare_env().
+ */
+static int patience_diff(mmfile_t *file1, mmfile_t *file2,
+ xpparam_t const *xpp, xdfenv_t *env,
+ int line1, int count1, int line2, int count2)
+{
+ struct hashmap map;
+ struct entry *first;
+ int result = 0;
+
+ /* trivial case: one side is empty */
+ if (!count1) {
+ while(count2--)
+ env->xdf2.rchg[line2++ - 1] = 1;
+ return 0;
+ } else if (!count2) {
+ while(count1--)
+ env->xdf1.rchg[line1++ - 1] = 1;
+ return 0;
+ }
+
+ memset(&map, 0, sizeof(map));
+ if (fill_hashmap(file1, file2, xpp, env, &map,
+ line1, count1, line2, count2))
+ return -1;
+
+ /* are there any matching lines at all? */
+ if (!map.has_matches) {
+ while(count1--)
+ env->xdf1.rchg[line1++ - 1] = 1;
+ while(count2--)
+ env->xdf2.rchg[line2++ - 1] = 1;
+ xdl_free(map.entries);
+ return 0;
+ }
+
+ first = find_longest_common_sequence(&map);
+ if (first)
+ result = walk_common_sequence(&map, first,
+ line1, count1, line2, count2);
+ else
+ result = fall_back_to_classic_diff(&map,
+ line1, count1, line2, count2);
+
+ xdl_free(map.entries);
+ return result;
+}
+
+int xdl_do_patience_diff(mmfile_t *file1, mmfile_t *file2,
+ xpparam_t const *xpp, xdfenv_t *env)
+{
+ if (xdl_prepare_env(file1, file2, xpp, env) < 0)
+ return -1;
+
+ /* environment is cleaned up in xdl_diff() */
+ return patience_diff(file1, file2, xpp, env,
+ 1, env->xdf1.nrec, 1, env->xdf2.nrec);
+}
diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index a43aa72..1689085 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -290,7 +290,8 @@ int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
xdl_free_classifier(&cf);
- if (xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
+ if (!(xpp->flags & XDF_PATIENCE_DIFF) &&
+ xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
xdl_free_ctx(&xe->xdf2);
xdl_free_ctx(&xe->xdf1);