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git-apply: parse the whole list of patches into memory first

Make it a clear two-phase thing: first a read-only parse of
the patch itself (which is independent of any current index
information), and then the second phase actually uses the patch.

The second phase might not be a real apply, it could be just a
diffstat, for example. Which is trivial to do once the patch is
parsed.
This commit is contained in:
Linus Torvalds 2005-05-26 10:23:51 -07:00
parent 368da62598
commit 19c58fb84d

236
apply.c
View File

@ -27,9 +27,23 @@ static const char apply_usage[] = "git-apply <patch>";
* things are flags, where -1 means "don't know yet".
*/
static int linenr = 1;
static int old_mode, new_mode;
static char *old_name, *new_name, *def_name;
static int is_rename, is_copy, is_new, is_delete;
static char *def_name = NULL;
struct fragment {
unsigned long oldpos, oldlines;
unsigned long newpos, newlines;
const char *patch;
int size;
struct fragment *next;
};
struct patch {
char *new_name, *old_name;
unsigned int old_mode, new_mode;
int is_rename, is_copy, is_new, is_delete;
struct fragment *fragments;
struct patch *next;
};
#define CHUNKSIZE (8192)
#define SLOP (16)
@ -159,7 +173,7 @@ static char * find_name(const char *line, char *def, int p_value, int terminate)
* files, we can happily check the index for a match, but for creating a
* new file we should try to match whatever "patch" does. I have no idea.
*/
static void parse_traditional_patch(const char *first, const char *second)
static void parse_traditional_patch(const char *first, const char *second, struct patch *patch)
{
int p_value = 1;
char *name;
@ -167,23 +181,25 @@ static void parse_traditional_patch(const char *first, const char *second)
first += 4; // skip "--- "
second += 4; // skip "+++ "
if (is_dev_null(first)) {
is_new = 1;
patch->is_new = 1;
patch->is_delete = 0;
name = find_name(second, def_name, p_value, TERM_SPACE | TERM_TAB);
new_name = name;
patch->new_name = name;
} else if (is_dev_null(second)) {
is_delete = 1;
patch->is_new = 0;
patch->is_delete = 1;
name = find_name(first, def_name, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
old_name = name;
patch->old_name = name;
} else {
name = find_name(first, def_name, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
name = find_name(second, name, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
old_name = new_name = name;
patch->old_name = patch->new_name = name;
}
if (!name)
die("unable to find filename in patch at line %d", linenr);
}
static int gitdiff_hdrend(const char *line)
static int gitdiff_hdrend(const char *line, struct patch *patch)
{
return -1;
}
@ -232,71 +248,71 @@ static char *gitdiff_verify_name(const char *line, int isnull, char *orig_name,
return NULL;
}
static int gitdiff_oldname(const char *line)
static int gitdiff_oldname(const char *line, struct patch *patch)
{
old_name = gitdiff_verify_name(line, is_new, old_name, "old");
patch->old_name = gitdiff_verify_name(line, patch->is_new, patch->old_name, "old");
return 0;
}
static int gitdiff_newname(const char *line)
static int gitdiff_newname(const char *line, struct patch *patch)
{
new_name = gitdiff_verify_name(line, is_delete, new_name, "new");
patch->new_name = gitdiff_verify_name(line, patch->is_delete, patch->new_name, "new");
return 0;
}
static int gitdiff_oldmode(const char *line)
static int gitdiff_oldmode(const char *line, struct patch *patch)
{
old_mode = strtoul(line, NULL, 8);
patch->old_mode = strtoul(line, NULL, 8);
return 0;
}
static int gitdiff_newmode(const char *line)
static int gitdiff_newmode(const char *line, struct patch *patch)
{
new_mode = strtoul(line, NULL, 8);
patch->new_mode = strtoul(line, NULL, 8);
return 0;
}
static int gitdiff_delete(const char *line)
static int gitdiff_delete(const char *line, struct patch *patch)
{
is_delete = 1;
return gitdiff_oldmode(line);
patch->is_delete = 1;
return gitdiff_oldmode(line, patch);
}
static int gitdiff_newfile(const char *line)
static int gitdiff_newfile(const char *line, struct patch *patch)
{
is_new = 1;
return gitdiff_newmode(line);
patch->is_new = 1;
return gitdiff_newmode(line, patch);
}
static int gitdiff_copysrc(const char *line)
static int gitdiff_copysrc(const char *line, struct patch *patch)
{
is_copy = 1;
old_name = find_name(line, NULL, 0, 0);
patch->is_copy = 1;
patch->old_name = find_name(line, NULL, 0, 0);
return 0;
}
static int gitdiff_copydst(const char *line)
static int gitdiff_copydst(const char *line, struct patch *patch)
{
is_copy = 1;
new_name = find_name(line, NULL, 0, 0);
patch->is_copy = 1;
patch->new_name = find_name(line, NULL, 0, 0);
return 0;
}
static int gitdiff_renamesrc(const char *line)
static int gitdiff_renamesrc(const char *line, struct patch *patch)
{
is_rename = 1;
old_name = find_name(line, NULL, 0, 0);
patch->is_rename = 1;
patch->old_name = find_name(line, NULL, 0, 0);
return 0;
}
static int gitdiff_renamedst(const char *line)
static int gitdiff_renamedst(const char *line, struct patch *patch)
{
is_rename = 1;
new_name = find_name(line, NULL, 0, 0);
patch->is_rename = 1;
patch->new_name = find_name(line, NULL, 0, 0);
return 0;
}
static int gitdiff_similarity(const char *line)
static int gitdiff_similarity(const char *line, struct patch *patch)
{
return 0;
}
@ -305,19 +321,19 @@ static int gitdiff_similarity(const char *line)
* This is normal for a diff that doesn't change anything: we'll fall through
* into the next diff. Tell the parser to break out.
*/
static int gitdiff_unrecognized(const char *line)
static int gitdiff_unrecognized(const char *line, struct patch *patch)
{
return -1;
}
/* Verify that we recognize the lines following a git header */
static int parse_git_header(char *line, int len, unsigned int size)
static int parse_git_header(char *line, int len, unsigned int size, struct patch *patch)
{
unsigned long offset;
/* A git diff has explicit new/delete information, so we don't guess */
is_new = 0;
is_delete = 0;
patch->is_new = 0;
patch->is_delete = 0;
line += len;
size -= len;
@ -325,7 +341,7 @@ static int parse_git_header(char *line, int len, unsigned int size)
for (offset = len ; size > 0 ; offset += len, size -= len, line += len, linenr++) {
static const struct opentry {
const char *str;
int (*fn)(const char *);
int (*fn)(const char *, struct patch *);
} optable[] = {
{ "@@ -", gitdiff_hdrend },
{ "--- ", gitdiff_oldname },
@ -351,7 +367,7 @@ static int parse_git_header(char *line, int len, unsigned int size)
int oplen = strlen(p->str);
if (len < oplen || memcmp(p->str, line, oplen))
continue;
if (p->fn(line + oplen) < 0)
if (p->fn(line + oplen, patch) < 0)
return offset;
break;
}
@ -393,7 +409,7 @@ static int parse_num(const char *line, int len, int offset, const char *expect,
* Parse a unified diff fragment header of the
* form "@@ -a,b +c,d @@"
*/
static int parse_fragment_header(char *line, int len, unsigned long *pos)
static int parse_fragment_header(char *line, int len, struct fragment *fragment)
{
int offset;
@ -401,22 +417,22 @@ static int parse_fragment_header(char *line, int len, unsigned long *pos)
return -1;
/* Figure out the number of lines in a fragment */
offset = parse_num(line, len, 4, ",", pos);
offset = parse_num(line, len, offset, " +", pos+1);
offset = parse_num(line, len, offset, ",", pos+2);
offset = parse_num(line, len, offset, " @@", pos+3);
offset = parse_num(line, len, 4, ",", &fragment->oldpos);
offset = parse_num(line, len, offset, " +", &fragment->oldlines);
offset = parse_num(line, len, offset, ",", &fragment->newpos);
offset = parse_num(line, len, offset, " @@", &fragment->newlines);
return offset;
}
static int find_header(char *line, unsigned long size, int *hdrsize)
static int find_header(char *line, unsigned long size, int *hdrsize, struct patch *patch)
{
unsigned long offset, len;
is_rename = is_copy = 0;
is_new = is_delete = -1;
old_mode = new_mode = 0;
def_name = old_name = new_name = NULL;
patch->is_rename = patch->is_copy = 0;
patch->is_new = patch->is_delete = -1;
patch->old_mode = patch->new_mode = 0;
patch->old_name = patch->new_name = NULL;
for (offset = 0; size > 0; offset += len, size -= len, line += len, linenr++) {
unsigned long nextlen;
@ -434,8 +450,8 @@ static int find_header(char *line, unsigned long size, int *hdrsize)
* patch has become corrupted/broken up.
*/
if (!memcmp("@@ -", line, 4)) {
unsigned long pos[4];
if (parse_fragment_header(line, len, pos) < 0)
struct fragment dummy;
if (parse_fragment_header(line, len, &dummy) < 0)
continue;
error("patch fragment without header at line %d: %.*s", linenr, len-1, line);
}
@ -448,7 +464,7 @@ static int find_header(char *line, unsigned long size, int *hdrsize)
* or mode change, so we handle that specially
*/
if (!memcmp("diff --git ", line, 11)) {
int git_hdr_len = parse_git_header(line, len, size);
int git_hdr_len = parse_git_header(line, len, size, patch);
if (git_hdr_len < 0)
continue;
@ -470,7 +486,7 @@ static int find_header(char *line, unsigned long size, int *hdrsize)
continue;
/* Ok, we'll consider it a patch */
parse_traditional_patch(line, line+len);
parse_traditional_patch(line, line+len, patch);
*hdrsize = len + nextlen;
linenr += 2;
return offset;
@ -485,21 +501,21 @@ static int find_header(char *line, unsigned long size, int *hdrsize)
* part of a patch, and a "---" that starts the next
* patch is to look at the line counts..
*/
static int apply_fragment(char *line, unsigned long size)
static int parse_fragment(char *line, unsigned long size, struct patch *patch, struct fragment *fragment)
{
int len = linelen(line, size), offset;
unsigned long pos[4], oldlines, newlines;
offset = parse_fragment_header(line, len, pos);
offset = parse_fragment_header(line, len, fragment);
if (offset < 0)
return -1;
oldlines = pos[1];
newlines = pos[3];
oldlines = fragment->oldlines;
newlines = fragment->newlines;
if (is_new < 0 && (pos[0] || oldlines))
is_new = 0;
if (is_delete < 0 && (pos[1] || newlines))
is_delete = 0;
if (patch->is_new < 0 && (pos[0] || oldlines))
patch->is_new = 0;
if (patch->is_delete < 0 && (pos[1] || newlines))
patch->is_delete = 0;
/* Parse the thing.. */
line += len;
@ -529,16 +545,26 @@ static int apply_fragment(char *line, unsigned long size)
return offset;
}
static int apply_single_patch(char *line, unsigned long size)
static int parse_single_patch(char *line, unsigned long size, struct patch *patch)
{
unsigned long offset = 0;
struct fragment **fragp = &patch->fragments;
while (size > 4 && !memcmp(line, "@@ -", 4)) {
int len = apply_fragment(line, size);
struct fragment *fragment;
int len;
fragment = xmalloc(sizeof(*fragment));
memset(fragment, 0, sizeof(*fragment));
len = parse_fragment(line, size, patch, fragment);
if (len <= 0)
die("corrupt patch at line %d", linenr);
printf("applying fragment:\n%.*s\n\n", len, line);
fragment->patch = line;
fragment->size = len;
*fragp = fragment;
fragp = &fragment->next;
offset += len;
line += len;
@ -547,52 +573,82 @@ printf("applying fragment:\n%.*s\n\n", len, line);
return offset;
}
static int apply_chunk(char *buffer, unsigned long size)
static int parse_chunk(char *buffer, unsigned long size, struct patch *patch)
{
int hdrsize, patchsize;
int offset = find_header(buffer, size, &hdrsize);
char *header, *patch;
int offset = find_header(buffer, size, &hdrsize, patch);
if (offset < 0)
return offset;
header = buffer + offset;
printf("Found header:\n%.*s\n\n", hdrsize, header);
printf("Rename: %d\n", is_rename);
printf("Copy: %d\n", is_copy);
printf("New: %d\n", is_new);
printf("Delete: %d\n", is_delete);
printf("Mode: %o:%o\n", old_mode, new_mode);
printf("Name: '%s':'%s'\n", old_name, new_name);
if (old_name && cache_name_pos(old_name, strlen(old_name)) < 0)
die("file %s does not exist", old_name);
if (new_name && (is_new | is_rename | is_copy)) {
if (cache_name_pos(new_name, strlen(new_name)) >= 0)
die("file %s already exists", new_name);
}
patch = header + hdrsize;
patchsize = apply_single_patch(patch, size - offset - hdrsize);
patchsize = parse_single_patch(buffer + offset + hdrsize, size - offset - hdrsize, patch);
return offset + hdrsize + patchsize;
}
static void apply_patch_list(struct patch *patch)
{
if (!patch)
die("no patch found");
do {
const char *old_name = patch->old_name;
const char *new_name = patch->new_name;
struct fragment *frag;
if (old_name) {
if (cache_name_pos(old_name, strlen(old_name)) < 0)
die("file %s does not exist", old_name);
if (patch->is_new < 0)
patch->is_new = 0;
}
if (new_name && (patch->is_new | patch->is_rename | patch->is_copy)) {
if (cache_name_pos(new_name, strlen(new_name)) >= 0)
die("file %s already exists", new_name);
}
printf("Applying patch to %s\n", new_name);
printf(" new=%d delete=%d copy=%d rename=%d\n",
patch->is_new, patch->is_delete, patch->is_copy, patch->is_rename);
if (patch->old_mode != patch->new_mode)
printf(" %o->%o\n", patch->old_mode, patch->new_mode);
frag = patch->fragments;
while (frag) {
printf("Fragment %lu,%lu -> %lu,%lu\n%.*s",
frag->oldpos, frag->oldlines,
frag->newpos, frag->newlines,
frag->size, frag->patch);
frag = frag->next;
}
} while ((patch = patch->next) != NULL);
}
static int apply_patch(int fd)
{
unsigned long offset, size;
char *buffer = read_patch_file(fd, &size);
struct patch *list = NULL, **listp = &list;
if (!buffer)
return -1;
offset = 0;
while (size > 0) {
int nr = apply_chunk(buffer + offset, size);
struct patch *patch;
int nr;
patch = xmalloc(sizeof(*patch));
memset(patch, 0, sizeof(*patch));
nr = parse_chunk(buffer + offset, size, patch);
if (nr < 0)
break;
*listp = patch;
listp = &patch->next;
offset += nr;
size -= nr;
}
apply_patch_list(list);
free(buffer);
return 0;
}