largefiles: remove meaningless code path for "hg pull --rebase"
This patch removes "--rebase" specific code path for "hg pull" in
"overridepull", because previous patch makes it meaningless: now,
"rebase.rebase" ("orig" invocation in this patch) can
update/commit largefiles safely without "repo._isrebasing = True".
As a side effect of removing "rebase.rebase" invocation in
"overridepull", this patch removes "nothing to rebase ..." message in
"test-largefiles.t", which is shown only when rebase extension is
enabled AFTER largefiles:
before this patch:
1. "dispatch" invokes "pullrebase" of rebase as "hg pull" at
first, because rebase wraps "hg pull" later
2. "pullrebase" invokes "overridepull" of largefiles as "orig",
even though rebase assumes that "orig" is "pull" of commands
3. "overridepull" executes "pull" and "rebase" directly
3.1 "pull" pulls changesets and creates new head "X"
3.2 "rebase" rebases current working parent "Y" on "X"
4. "overridepull" returns to "pullrebase"
5. "pullrebase" tries to rebase, but there is nothing to be done,
because "Y" is already rebased on "X". then, it shows "nothing
to rebase ..."
after this patch:
1. "dispatch" invokes "pullrebase" of rebase as "hg pull"
2. "pullrebase" invokes "overridepull" of largefiles as "orig"
3. "overridepull" executes "pull" as "orig"
4. "overridepull" returns to "pullrebase"
5. revision "Y" is not yet rebased, so "pullrebase" doesn't shows
"nothing to rebase ..."
As another side effect of removing "rebase.rebase" invocation, this
patch fixes issue3861, which occurs only when rebase extension is
enabled BEFORE largefiles:
before this patch:
1. "dispatch" invokes "overridepull" of largefiles at first,
because largefiles wrap "hg pull" later
2. "overridepull" executes "pull" and "rebase" explicitly
2.1 "pull" pulls changesets and creates new head "X"
2.2 "rebase" rebases current working parent, but fails because
no revision is checked out in issue3861 case
3. "overridepull" returns to "dispatch" with exit code 1 returned
from "rebase" at (2.2)
4. "hg pull" terminates with exit code 1 unexpectedly
after this patch:
1. "dispatch" invokes "overridepull" of largefiles at first
2. "overridepull" invokes "pullrebase" of rebase as "orig"
3. "pullrebase" invokes "pull" as "orig"
4. "pullrebase" invokes "rebase", and it fails
5. "pullrebase" returns to "overridepull" with exit code 0
(because "pullrebase" ignores result of "pull" and "rebase")
6. "overridepull" returns to "dispatch" with exit code 0 returned
from "rebase" at (5)
7. "hg pull" terminates with exit code 0
/*
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
*/
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "util.h"
struct line {
int hash, n, e;
Py_ssize_t len;
const char *l;
};
struct pos {
int pos, len;
};
struct hunk;
struct hunk {
int a1, a2, b1, b2;
struct hunk *next;
};
static int splitlines(const char *a, Py_ssize_t len, struct line **lr)
{
unsigned hash;
int 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 */
hash = 0;
for (p = a; p < a + len; p++) {
/* Leonid Yuriev's hash */
hash = (hash * 1664525) + (unsigned char)*p + 1013904223;
if (*p == '\n' || p == plast) {
l->hash = hash;
hash = 0;
l->len = p - b + 1;
l->l = b;
l->n = INT_MAX;
l++;
b = p + 1;
}
}
/* set up a sentinel */
l->hash = 0;
l->len = 0;
l->l = a + len;
return i - 1;
}
static inline int cmp(struct line *a, struct line *b)
{
return a->hash != b->hash || 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].hash & 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 >= 31000) ? bn / 1000 : 1000000 / (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].hash & 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 struct hunk *recurse(struct line *a, struct line *b, struct pos *pos,
int a1, int a2, int b1, int b2, struct hunk *l)
{
int i, j, k;
while (1) {
/* find the longest match in this chunk */
k = longest_match(a, b, pos, a1, a2, b1, b2, &i, &j);
if (!k)
return l;
/* and recurse on the remaining chunks on either side */
l = recurse(a, b, pos, a1, i, b1, j, l);
if (!l)
return NULL;
l->next = (struct hunk *)malloc(sizeof(struct hunk));
if (!l->next)
return NULL;
l = l->next;
l->a1 = i;
l->a2 = i + k;
l->b1 = j;
l->b2 = j + k;
l->next = NULL;
/* tail-recursion didn't happen, so do equivalent iteration */
a1 = i + k;
b1 = j + k;
}
}
static int diff(struct line *a, int an, struct line *b, int bn,
struct hunk *base)
{
struct hunk *curr;
struct pos *pos;
int t, count = 0;
/* allocate and fill arrays */
t = equatelines(a, an, b, bn);
pos = (struct pos *)calloc(bn ? bn : 1, sizeof(struct pos));
if (pos && t) {
/* generate the matching block list */
curr = recurse(a, b, pos, 0, an, 0, bn, base);
if (!curr)
return -1;
/* sentinel end hunk */
curr->next = (struct hunk *)malloc(sizeof(struct hunk));
if (!curr->next)
return -1;
curr = curr->next;
curr->a1 = curr->a2 = an;
curr->b1 = curr->b2 = bn;
curr->next = NULL;
}
free(pos);
/* normalize the hunk list, try to push each hunk towards the end */
for (curr = base->next; curr; curr = curr->next) {
struct hunk *next = curr->next;
int shift = 0;
if (!next)
break;
if (curr->a2 == next->a1)
while (curr->a2 + shift < an && curr->b2 + shift < bn
&& !cmp(a + curr->a2 + shift,
b + curr->b2 + shift))
shift++;
else if (curr->b2 == next->b1)
while (curr->b2 + shift < bn && curr->a2 + shift < an
&& !cmp(b + curr->b2 + shift,
a + curr->a2 + shift))
shift++;
if (!shift)
continue;
curr->b2 += shift;
next->b1 += shift;
curr->a2 += shift;
next->a1 += shift;
}
for (curr = base->next; curr; curr = curr->next)
count++;
return count;
}
static void freehunks(struct hunk *l)
{
struct hunk *n;
for (; l; l = n) {
n = l->next;
free(l);
}
}
static PyObject *blocks(PyObject *self, PyObject *args)
{
PyObject *sa, *sb, *rl = NULL, *m;
struct line *a, *b;
struct hunk l, *h;
int an, bn, count, pos = 0;
l.next = NULL;
if (!PyArg_ParseTuple(args, "SS:bdiff", &sa, &sb))
return NULL;
an = splitlines(PyBytes_AsString(sa), PyBytes_Size(sa), &a);
bn = splitlines(PyBytes_AsString(sb), PyBytes_Size(sb), &b);
if (!a || !b)
goto nomem;
count = diff(a, an, b, bn, &l);
if (count < 0)
goto nomem;
rl = PyList_New(count);
if (!rl)
goto nomem;
for (h = l.next; h; h = h->next) {
m = Py_BuildValue("iiii", h->a1, h->a2, h->b1, h->b2);
PyList_SetItem(rl, pos, m);
pos++;
}
nomem:
free(a);
free(b);
freehunks(l.next);
return rl ? rl : PyErr_NoMemory();
}
static PyObject *bdiff(PyObject *self, PyObject *args)
{
char *sa, *sb, *rb;
PyObject *result = NULL;
struct line *al, *bl;
struct hunk l, *h;
int an, bn, count;
Py_ssize_t len = 0, la, lb;
PyThreadState *_save;
l.next = NULL;
if (!PyArg_ParseTuple(args, "s#s#:bdiff", &sa, &la, &sb, &lb))
return NULL;
if (la > UINT_MAX || lb > UINT_MAX) {
PyErr_SetString(PyExc_ValueError, "bdiff inputs too large");
return NULL;
}
_save = PyEval_SaveThread();
an = splitlines(sa, la, &al);
bn = splitlines(sb, lb, &bl);
if (!al || !bl)
goto nomem;
count = diff(al, an, bl, bn, &l);
if (count < 0)
goto nomem;
/* calculate length of output */
la = lb = 0;
for (h = l.next; h; h = h->next) {
if (h->a1 != la || h->b1 != lb)
len += 12 + bl[h->b1].l - bl[lb].l;
la = h->a2;
lb = h->b2;
}
PyEval_RestoreThread(_save);
_save = NULL;
result = PyBytes_FromStringAndSize(NULL, len);
if (!result)
goto nomem;
/* build binary patch */
rb = PyBytes_AsString(result);
la = lb = 0;
for (h = l.next; h; h = h->next) {
if (h->a1 != la || h->b1 != lb) {
len = bl[h->b1].l - bl[lb].l;
putbe32((uint32_t)(al[la].l - al->l), rb);
putbe32((uint32_t)(al[h->a1].l - al->l), rb + 4);
putbe32((uint32_t)len, rb + 8);
memcpy(rb + 12, bl[lb].l, len);
rb += 12 + len;
}
la = h->a2;
lb = h->b2;
}
nomem:
if (_save)
PyEval_RestoreThread(_save);
free(al);
free(bl);
freehunks(l.next);
return result ? result : PyErr_NoMemory();
}
/*
* If allws != 0, remove all whitespace (' ', \t and \r). Otherwise,
* reduce whitespace sequences to a single space and trim remaining whitespace
* from end of lines.
*/
static PyObject *fixws(PyObject *self, PyObject *args)
{
PyObject *s, *result = NULL;
char allws, c;
const char *r;
Py_ssize_t i, rlen, wlen = 0;
char *w;
if (!PyArg_ParseTuple(args, "Sb:fixws", &s, &allws))
return NULL;
r = PyBytes_AsString(s);
rlen = PyBytes_Size(s);
w = (char *)malloc(rlen ? rlen : 1);
if (!w)
goto nomem;
for (i = 0; i != rlen; i++) {
c = r[i];
if (c == ' ' || c == '\t' || c == '\r') {
if (!allws && (wlen == 0 || w[wlen - 1] != ' '))
w[wlen++] = ' ';
} else if (c == '\n' && !allws
&& wlen > 0 && w[wlen - 1] == ' ') {
w[wlen - 1] = '\n';
} else {
w[wlen++] = c;
}
}
result = PyBytes_FromStringAndSize(w, wlen);
nomem:
free(w);
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"},
{"fixws", fixws, METH_VARARGS, "normalize diff whitespaces\n"},
{NULL, NULL}
};
#ifdef IS_PY3K
static struct PyModuleDef bdiff_module = {
PyModuleDef_HEAD_INIT,
"bdiff",
mdiff_doc,
-1,
methods
};
PyMODINIT_FUNC PyInit_bdiff(void)
{
return PyModule_Create(&bdiff_module);
}
#else
PyMODINIT_FUNC initbdiff(void)
{
Py_InitModule3("bdiff", methods, mdiff_doc);
}
#endif