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localrepo.commit: normalize commit message even for rawcommit....
localrepo.commit: normalize commit message even for rawcommit. This normalization consists of: - stripping trailing whitespace - always using "\n" as the line separator I think the main reason rawcommit was skipping this normalization was an attempt to preserve hashes during an hg->hg conversion. While this is a nice goal, it's not particularly interesting in practice. Since SHA-1 is so strong, the only safe way to do it is to have absolutely identical revisions. But: - if the original revision was created with a recent version of hg, the commit message will be the same, with or without that normalization - if it was created with an ancient version of hg that didn't do any normalization, even if the commit message is identical, the file list in the changelog is likely to be different (e.g. no removed files), and there were some old issues with e.g. extra file merging, which will end up changing the hash anyway - in any case, if one *really* has to preserve hashes, it's easier (and faster) to fake a partial conversion using something like: hg clone -U -r rev orig-repo new-repo hg -R new-repo log --template '#node# #node#\n' > new-repo/.hg/shamap Additionally, we've had some reports of problems arising from this lack of normalization - e.g. issue871, and a user that was wondering why hg export/hg import was not preserving hashes when there was nothing unusual going on (it was just import doing the normalization that had been skipped). This also means that it's even more unlikely to get identical revisions when going $VCS->hg->$VCS.

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r5620:652f57de merge default
r6254:3667b6e4 default
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bdiff.c
371 lines | 7.8 KiB | text/x-c | CLexer
/*
bdiff.c - efficient binary diff extension for Mercurial
Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
This software may be used and distributed according to the terms of
the GNU General Public License, incorporated herein by reference.
Based roughly on Python difflib
*/
#include <Python.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#if defined __hpux || defined __SUNPRO_C || defined _AIX
# define inline
#endif
#ifdef _WIN32
#ifdef _MSC_VER
#define inline __inline
typedef unsigned long uint32_t;
#else
#include <stdint.h>
#endif
static uint32_t htonl(uint32_t x)
{
return ((x & 0x000000ffUL) << 24) |
((x & 0x0000ff00UL) << 8) |
((x & 0x00ff0000UL) >> 8) |
((x & 0xff000000UL) >> 24);
}
#else
#include <sys/types.h>
#ifdef __BEOS__
#include <ByteOrder.h>
#else
#include <arpa/inet.h>
#endif
#include <inttypes.h>
#endif
struct line {
int h, len, n, e;
const char *l;
};
struct pos {
int pos, len;
};
struct hunk {
int a1, a2, b1, b2;
};
struct hunklist {
struct hunk *base, *head;
};
int splitlines(const char *a, int len, struct line **lr)
{
int h, i;
const char *p, *b = a;
const char * const plast = a + len - 1;
struct line *l;
/* count the lines */
i = 1; /* extra line for sentinel */
for (p = a; p < a + len; p++)
if (*p == '\n' || p == plast)
i++;
*lr = l = (struct line *)malloc(sizeof(struct line) * i);
if (!l)
return -1;
/* build the line array and calculate hashes */
h = 0;
for (p = a; p < a + len; p++) {
/* Leonid Yuriev's hash */
h = (h * 1664525) + *p + 1013904223;
if (*p == '\n' || p == plast) {
l->h = h;
h = 0;
l->len = p - b + 1;
l->l = b;
l->n = INT_MAX;
l++;
b = p + 1;
}
}
/* set up a sentinel */
l->h = l->len = 0;
l->l = a + len;
return i - 1;
}
int inline cmp(struct line *a, struct line *b)
{
return a->h != b->h || a->len != b->len || memcmp(a->l, b->l, a->len);
}
static int equatelines(struct line *a, int an, struct line *b, int bn)
{
int i, j, buckets = 1, t, scale;
struct pos *h = NULL;
/* build a hash table of the next highest power of 2 */
while (buckets < bn + 1)
buckets *= 2;
/* try to allocate a large hash table to avoid collisions */
for (scale = 4; scale; scale /= 2) {
h = (struct pos *)malloc(scale * buckets * sizeof(struct pos));
if (h)
break;
}
if (!h)
return 0;
buckets = buckets * scale - 1;
/* clear the hash table */
for (i = 0; i <= buckets; i++) {
h[i].pos = INT_MAX;
h[i].len = 0;
}
/* add lines to the hash table chains */
for (i = bn - 1; i >= 0; i--) {
/* find the equivalence class */
for (j = b[i].h & buckets; h[j].pos != INT_MAX;
j = (j + 1) & buckets)
if (!cmp(b + i, b + h[j].pos))
break;
/* add to the head of the equivalence class */
b[i].n = h[j].pos;
b[i].e = j;
h[j].pos = i;
h[j].len++; /* keep track of popularity */
}
/* compute popularity threshold */
t = (bn >= 4000) ? bn / 1000 : bn + 1;
/* match items in a to their equivalence class in b */
for (i = 0; i < an; i++) {
/* find the equivalence class */
for (j = a[i].h & buckets; h[j].pos != INT_MAX;
j = (j + 1) & buckets)
if (!cmp(a + i, b + h[j].pos))
break;
a[i].e = j; /* use equivalence class for quick compare */
if (h[j].len <= t)
a[i].n = h[j].pos; /* point to head of match list */
else
a[i].n = INT_MAX; /* too popular */
}
/* discard hash tables */
free(h);
return 1;
}
static int longest_match(struct line *a, struct line *b, struct pos *pos,
int a1, int a2, int b1, int b2, int *omi, int *omj)
{
int mi = a1, mj = b1, mk = 0, mb = 0, i, j, k;
for (i = a1; i < a2; i++) {
/* skip things before the current block */
for (j = a[i].n; j < b1; j = b[j].n)
;
/* loop through all lines match a[i] in b */
for (; j < b2; j = b[j].n) {
/* does this extend an earlier match? */
if (i > a1 && j > b1 && pos[j - 1].pos == i - 1)
k = pos[j - 1].len + 1;
else
k = 1;
pos[j].pos = i;
pos[j].len = k;
/* best match so far? */
if (k > mk) {
mi = i;
mj = j;
mk = k;
}
}
}
if (mk) {
mi = mi - mk + 1;
mj = mj - mk + 1;
}
/* expand match to include neighboring popular lines */
while (mi - mb > a1 && mj - mb > b1 &&
a[mi - mb - 1].e == b[mj - mb - 1].e)
mb++;
while (mi + mk < a2 && mj + mk < b2 &&
a[mi + mk].e == b[mj + mk].e)
mk++;
*omi = mi - mb;
*omj = mj - mb;
return mk + mb;
}
static void recurse(struct line *a, struct line *b, struct pos *pos,
int a1, int a2, int b1, int b2, struct hunklist *l)
{
int i, j, k;
/* find the longest match in this chunk */
k = longest_match(a, b, pos, a1, a2, b1, b2, &i, &j);
if (!k)
return;
/* and recurse on the remaining chunks on either side */
recurse(a, b, pos, a1, i, b1, j, l);
l->head->a1 = i;
l->head->a2 = i + k;
l->head->b1 = j;
l->head->b2 = j + k;
l->head++;
recurse(a, b, pos, i + k, a2, j + k, b2, l);
}
static struct hunklist diff(struct line *a, int an, struct line *b, int bn)
{
struct hunklist l;
struct pos *pos;
int t;
/* allocate and fill arrays */
t = equatelines(a, an, b, bn);
pos = (struct pos *)calloc(bn ? bn : 1, sizeof(struct pos));
/* we can't have more matches than lines in the shorter file */
l.head = l.base = (struct hunk *)malloc(sizeof(struct hunk) *
((an<bn ? an:bn) + 1));
if (pos && l.base && t) {
/* generate the matching block list */
recurse(a, b, pos, 0, an, 0, bn, &l);
l.head->a1 = l.head->a2 = an;
l.head->b1 = l.head->b2 = bn;
l.head++;
}
free(pos);
return l;
}
static PyObject *blocks(PyObject *self, PyObject *args)
{
PyObject *sa, *sb, *rl = NULL, *m;
struct line *a, *b;
struct hunklist l = {NULL, NULL};
struct hunk *h;
int an, bn, pos = 0;
if (!PyArg_ParseTuple(args, "SS:bdiff", &sa, &sb))
return NULL;
an = splitlines(PyString_AsString(sa), PyString_Size(sa), &a);
bn = splitlines(PyString_AsString(sb), PyString_Size(sb), &b);
if (!a || !b)
goto nomem;
l = diff(a, an, b, bn);
rl = PyList_New(l.head - l.base);
if (!l.head || !rl)
goto nomem;
for (h = l.base; h != l.head; h++) {
m = Py_BuildValue("iiii", h->a1, h->a2, h->b1, h->b2);
PyList_SetItem(rl, pos, m);
pos++;
}
nomem:
free(a);
free(b);
free(l.base);
return rl ? rl : PyErr_NoMemory();
}
static PyObject *bdiff(PyObject *self, PyObject *args)
{
char *sa, *sb;
PyObject *result = NULL;
struct line *al, *bl;
struct hunklist l = {NULL, NULL};
struct hunk *h;
char encode[12], *rb;
int an, bn, len = 0, la, lb;
if (!PyArg_ParseTuple(args, "s#s#:bdiff", &sa, &la, &sb, &lb))
return NULL;
an = splitlines(sa, la, &al);
bn = splitlines(sb, lb, &bl);
if (!al || !bl)
goto nomem;
l = diff(al, an, bl, bn);
if (!l.head)
goto nomem;
/* calculate length of output */
la = lb = 0;
for (h = l.base; h != l.head; h++) {
if (h->a1 != la || h->b1 != lb)
len += 12 + bl[h->b1].l - bl[lb].l;
la = h->a2;
lb = h->b2;
}
result = PyString_FromStringAndSize(NULL, len);
if (!result)
goto nomem;
/* build binary patch */
rb = PyString_AsString(result);
la = lb = 0;
for (h = l.base; h != l.head; h++) {
if (h->a1 != la || h->b1 != lb) {
len = bl[h->b1].l - bl[lb].l;
*(uint32_t *)(encode) = htonl(al[la].l - al->l);
*(uint32_t *)(encode + 4) = htonl(al[h->a1].l - al->l);
*(uint32_t *)(encode + 8) = htonl(len);
memcpy(rb, encode, 12);
memcpy(rb + 12, bl[lb].l, len);
rb += 12 + len;
}
la = h->a2;
lb = h->b2;
}
nomem:
free(al);
free(bl);
free(l.base);
return result ? result : PyErr_NoMemory();
}
static char mdiff_doc[] = "Efficient binary diff.";
static PyMethodDef methods[] = {
{"bdiff", bdiff, METH_VARARGS, "calculate a binary diff\n"},
{"blocks", blocks, METH_VARARGS, "find a list of matching lines\n"},
{NULL, NULL}
};
PyMODINIT_FUNC initbdiff(void)
{
Py_InitModule3("bdiff", methods, mdiff_doc);
}