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git/commit.c
Sergey Vlasov 4a4e6fd74f Rework object refs tracking to reduce memory usage
Store pointers to referenced objects in a variable sized array instead
of linked list.  This cuts down memory usage of utilities which use
object references; e.g., git-fsck-objects --full on the git.git
repository consumes about 2 MB of memory tracked by Massif instead of
7 MB before the change.  Object refs are still the biggest consumer of
memory (57%), but the malloc overhead for a single block instead of a
linked list is substantially smaller.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-11-15 11:42:29 -08:00

637 lines
14 KiB
C

#include "tag.h"
#include "commit.h"
#include "cache.h"
int save_commit_buffer = 1;
struct sort_node
{
/*
* the number of children of the associated commit
* that also occur in the list being sorted.
*/
unsigned int indegree;
/*
* reference to original list item that we will re-use
* on output.
*/
struct commit_list * list_item;
};
const char *commit_type = "commit";
enum cmit_fmt get_commit_format(const char *arg)
{
if (!*arg)
return CMIT_FMT_DEFAULT;
if (!strcmp(arg, "=raw"))
return CMIT_FMT_RAW;
if (!strcmp(arg, "=medium"))
return CMIT_FMT_MEDIUM;
if (!strcmp(arg, "=short"))
return CMIT_FMT_SHORT;
if (!strcmp(arg, "=full"))
return CMIT_FMT_FULL;
if (!strcmp(arg, "=fuller"))
return CMIT_FMT_FULLER;
if (!strcmp(arg, "=oneline"))
return CMIT_FMT_ONELINE;
die("invalid --pretty format");
}
static struct commit *check_commit(struct object *obj,
const unsigned char *sha1,
int quiet)
{
if (obj->type != commit_type) {
if (!quiet)
error("Object %s is a %s, not a commit",
sha1_to_hex(sha1), obj->type);
return NULL;
}
return (struct commit *) obj;
}
struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
int quiet)
{
struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
if (!obj)
return NULL;
return check_commit(obj, sha1, quiet);
}
struct commit *lookup_commit_reference(const unsigned char *sha1)
{
return lookup_commit_reference_gently(sha1, 0);
}
struct commit *lookup_commit(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj) {
struct commit *ret = xmalloc(sizeof(struct commit));
memset(ret, 0, sizeof(struct commit));
created_object(sha1, &ret->object);
ret->object.type = commit_type;
return ret;
}
if (!obj->type)
obj->type = commit_type;
return check_commit(obj, sha1, 0);
}
static unsigned long parse_commit_date(const char *buf)
{
unsigned long date;
if (memcmp(buf, "author", 6))
return 0;
while (*buf++ != '\n')
/* nada */;
if (memcmp(buf, "committer", 9))
return 0;
while (*buf++ != '>')
/* nada */;
date = strtoul(buf, NULL, 10);
if (date == ULONG_MAX)
date = 0;
return date;
}
static struct commit_graft {
unsigned char sha1[20];
int nr_parent;
unsigned char parent[0][20]; /* more */
} **commit_graft;
static int commit_graft_alloc, commit_graft_nr;
static int commit_graft_pos(const unsigned char *sha1)
{
int lo, hi;
lo = 0;
hi = commit_graft_nr;
while (lo < hi) {
int mi = (lo + hi) / 2;
struct commit_graft *graft = commit_graft[mi];
int cmp = memcmp(sha1, graft->sha1, 20);
if (!cmp)
return mi;
if (cmp < 0)
hi = mi;
else
lo = mi + 1;
}
return -lo - 1;
}
static void prepare_commit_graft(void)
{
char *graft_file = get_graft_file();
FILE *fp = fopen(graft_file, "r");
char buf[1024];
if (!fp) {
commit_graft = (struct commit_graft **) "hack";
return;
}
while (fgets(buf, sizeof(buf), fp)) {
/* The format is just "Commit Parent1 Parent2 ...\n" */
int len = strlen(buf);
int i;
struct commit_graft *graft = NULL;
if (buf[len-1] == '\n')
buf[--len] = 0;
if (buf[0] == '#')
continue;
if ((len + 1) % 41) {
bad_graft_data:
error("bad graft data: %s", buf);
free(graft);
continue;
}
i = (len + 1) / 41 - 1;
graft = xmalloc(sizeof(*graft) + 20 * i);
graft->nr_parent = i;
if (get_sha1_hex(buf, graft->sha1))
goto bad_graft_data;
for (i = 40; i < len; i += 41) {
if (buf[i] != ' ')
goto bad_graft_data;
if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
goto bad_graft_data;
}
i = commit_graft_pos(graft->sha1);
if (0 <= i) {
error("duplicate graft data: %s", buf);
free(graft);
continue;
}
i = -i - 1;
if (commit_graft_alloc <= ++commit_graft_nr) {
commit_graft_alloc = alloc_nr(commit_graft_alloc);
commit_graft = xrealloc(commit_graft,
sizeof(*commit_graft) *
commit_graft_alloc);
}
if (i < commit_graft_nr)
memmove(commit_graft + i + 1,
commit_graft + i,
(commit_graft_nr - i - 1) *
sizeof(*commit_graft));
commit_graft[i] = graft;
}
fclose(fp);
}
static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
{
int pos;
if (!commit_graft)
prepare_commit_graft();
pos = commit_graft_pos(sha1);
if (pos < 0)
return NULL;
return commit_graft[pos];
}
int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
{
char *bufptr = buffer;
unsigned char parent[20];
struct commit_list **pptr;
struct commit_graft *graft;
unsigned n_refs = 0;
if (item->object.parsed)
return 0;
item->object.parsed = 1;
if (memcmp(bufptr, "tree ", 5))
return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
if (get_sha1_hex(bufptr + 5, parent) < 0)
return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
item->tree = lookup_tree(parent);
if (item->tree)
n_refs++;
bufptr += 46; /* "tree " + "hex sha1" + "\n" */
pptr = &item->parents;
graft = lookup_commit_graft(item->object.sha1);
while (!memcmp(bufptr, "parent ", 7)) {
struct commit *new_parent;
if (get_sha1_hex(bufptr + 7, parent) || bufptr[47] != '\n')
return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
bufptr += 48;
if (graft)
continue;
new_parent = lookup_commit(parent);
if (new_parent) {
pptr = &commit_list_insert(new_parent, pptr)->next;
n_refs++;
}
}
if (graft) {
int i;
struct commit *new_parent;
for (i = 0; i < graft->nr_parent; i++) {
new_parent = lookup_commit(graft->parent[i]);
if (!new_parent)
continue;
pptr = &commit_list_insert(new_parent, pptr)->next;
n_refs++;
}
}
item->date = parse_commit_date(bufptr);
if (track_object_refs) {
unsigned i = 0;
struct commit_list *p;
struct object_refs *refs = alloc_object_refs(n_refs);
if (item->tree)
refs->ref[i++] = &item->tree->object;
for (p = item->parents; p; p = p->next)
refs->ref[i++] = &p->item->object;
set_object_refs(&item->object, refs);
}
return 0;
}
int parse_commit(struct commit *item)
{
char type[20];
void *buffer;
unsigned long size;
int ret;
if (item->object.parsed)
return 0;
buffer = read_sha1_file(item->object.sha1, type, &size);
if (!buffer)
return error("Could not read %s",
sha1_to_hex(item->object.sha1));
if (strcmp(type, commit_type)) {
free(buffer);
return error("Object %s not a commit",
sha1_to_hex(item->object.sha1));
}
ret = parse_commit_buffer(item, buffer, size);
if (save_commit_buffer && !ret) {
item->buffer = buffer;
return 0;
}
free(buffer);
return ret;
}
struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
{
struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
new_list->item = item;
new_list->next = *list_p;
*list_p = new_list;
return new_list;
}
void free_commit_list(struct commit_list *list)
{
while (list) {
struct commit_list *temp = list;
list = temp->next;
free(temp);
}
}
struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
{
struct commit_list **pp = list;
struct commit_list *p;
while ((p = *pp) != NULL) {
if (p->item->date < item->date) {
break;
}
pp = &p->next;
}
return commit_list_insert(item, pp);
}
void sort_by_date(struct commit_list **list)
{
struct commit_list *ret = NULL;
while (*list) {
insert_by_date((*list)->item, &ret);
*list = (*list)->next;
}
*list = ret;
}
struct commit *pop_most_recent_commit(struct commit_list **list,
unsigned int mark)
{
struct commit *ret = (*list)->item;
struct commit_list *parents = ret->parents;
struct commit_list *old = *list;
*list = (*list)->next;
free(old);
while (parents) {
struct commit *commit = parents->item;
parse_commit(commit);
if (!(commit->object.flags & mark)) {
commit->object.flags |= mark;
insert_by_date(commit, list);
}
parents = parents->next;
}
return ret;
}
/*
* Generic support for pretty-printing the header
*/
static int get_one_line(const char *msg, unsigned long len)
{
int ret = 0;
while (len--) {
char c = *msg++;
ret++;
if (c == '\n')
break;
if (!c)
return 0;
}
return ret;
}
static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
{
char *date;
int namelen;
unsigned long time;
int tz, ret;
const char *filler = " ";
if (fmt == CMIT_FMT_ONELINE)
return 0;
date = strchr(line, '>');
if (!date)
return 0;
namelen = ++date - line;
time = strtoul(date, &date, 10);
tz = strtol(date, NULL, 10);
ret = sprintf(buf, "%s: %.*s%.*s\n", what,
(fmt == CMIT_FMT_FULLER) ? 4 : 0,
filler, namelen, line);
switch (fmt) {
case CMIT_FMT_MEDIUM:
ret += sprintf(buf + ret, "Date: %s\n", show_date(time, tz));
break;
case CMIT_FMT_FULLER:
ret += sprintf(buf + ret, "%sDate: %s\n", what, show_date(time, tz));
break;
default:
/* notin' */
break;
}
return ret;
}
static int is_empty_line(const char *line, int len)
{
while (len && isspace(line[len-1]))
len--;
return !len;
}
static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
{
int offset = 0;
if (fmt == CMIT_FMT_ONELINE)
return offset;
switch (parents) {
case 1:
break;
case 2:
/* Go back to the previous line: 40 characters of previous parent, and one '\n' */
offset = sprintf(buf, "Merge: %.40s\n", line-41);
/* Fallthrough */
default:
/* Replace the previous '\n' with a space */
buf[offset-1] = ' ';
offset += sprintf(buf + offset, "%.40s\n", line+7);
}
return offset;
}
unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
{
int hdr = 1, body = 0;
unsigned long offset = 0;
int parents = 0;
int indent = (fmt == CMIT_FMT_ONELINE) ? 0 : 4;
for (;;) {
const char *line = msg;
int linelen = get_one_line(msg, len);
if (!linelen)
break;
/*
* We want some slop for indentation and a possible
* final "...". Thus the "+ 20".
*/
if (offset + linelen + 20 > space) {
memcpy(buf + offset, " ...\n", 8);
offset += 8;
break;
}
msg += linelen;
len -= linelen;
if (hdr) {
if (linelen == 1) {
hdr = 0;
if (fmt != CMIT_FMT_ONELINE)
buf[offset++] = '\n';
continue;
}
if (fmt == CMIT_FMT_RAW) {
memcpy(buf + offset, line, linelen);
offset += linelen;
continue;
}
if (!memcmp(line, "parent ", 7)) {
if (linelen != 48)
die("bad parent line in commit");
offset += add_parent_info(fmt, buf + offset, line, ++parents);
}
/*
* MEDIUM == DEFAULT shows only author with dates.
* FULL shows both authors but not dates.
* FULLER shows both authors and dates.
*/
if (!memcmp(line, "author ", 7))
offset += add_user_info("Author", fmt,
buf + offset,
line + 7);
if (!memcmp(line, "committer ", 10) &&
(fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
offset += add_user_info("Commit", fmt,
buf + offset,
line + 10);
continue;
}
if (is_empty_line(line, linelen)) {
if (!body)
continue;
if (fmt == CMIT_FMT_SHORT)
break;
} else {
body = 1;
}
memset(buf + offset, ' ', indent);
memcpy(buf + offset + indent, line, linelen);
offset += linelen + indent;
if (fmt == CMIT_FMT_ONELINE)
break;
}
if (fmt == CMIT_FMT_ONELINE) {
/* We do not want the terminating newline */
if (buf[offset - 1] == '\n')
offset--;
}
else {
/* Make sure there is an EOLN */
if (buf[offset - 1] != '\n')
buf[offset++] = '\n';
}
buf[offset] = '\0';
return offset;
}
struct commit *pop_commit(struct commit_list **stack)
{
struct commit_list *top = *stack;
struct commit *item = top ? top->item : NULL;
if (top) {
*stack = top->next;
free(top);
}
return item;
}
int count_parents(struct commit * commit)
{
int count = 0;
struct commit_list * parents = commit->parents;
for (count=0;parents; parents=parents->next,count++)
;
return count;
}
/*
* Performs an in-place topological sort on the list supplied.
*/
void sort_in_topological_order(struct commit_list ** list)
{
struct commit_list * next = *list;
struct commit_list * work = NULL, **insert;
struct commit_list ** pptr = list;
struct sort_node * nodes;
struct sort_node * next_nodes;
int count = 0;
/* determine the size of the list */
while (next) {
next = next->next;
count++;
}
/* allocate an array to help sort the list */
nodes = xcalloc(count, sizeof(*nodes));
/* link the list to the array */
next_nodes = nodes;
next=*list;
while (next) {
next_nodes->list_item = next;
next->item->object.util = next_nodes;
next_nodes++;
next = next->next;
}
/* update the indegree */
next=*list;
while (next) {
struct commit_list * parents = next->item->parents;
while (parents) {
struct commit * parent=parents->item;
struct sort_node * pn = (struct sort_node *)parent->object.util;
if (pn)
pn->indegree++;
parents=parents->next;
}
next=next->next;
}
/*
* find the tips
*
* tips are nodes not reachable from any other node in the list
*
* the tips serve as a starting set for the work queue.
*/
next=*list;
insert = &work;
while (next) {
struct sort_node * node = (struct sort_node *)next->item->object.util;
if (node->indegree == 0) {
insert = &commit_list_insert(next->item, insert)->next;
}
next=next->next;
}
/* process the list in topological order */
while (work) {
struct commit * work_item = pop_commit(&work);
struct sort_node * work_node = (struct sort_node *)work_item->object.util;
struct commit_list * parents = work_item->parents;
while (parents) {
struct commit * parent=parents->item;
struct sort_node * pn = (struct sort_node *)parent->object.util;
if (pn) {
/*
* parents are only enqueued for emission
* when all their children have been emitted thereby
* guaranteeing topological order.
*/
pn->indegree--;
if (!pn->indegree)
commit_list_insert(parent, &work);
}
parents=parents->next;
}
/*
* work_item is a commit all of whose children
* have already been emitted. we can emit it now.
*/
*pptr = work_node->list_item;
pptr = &(*pptr)->next;
*pptr = NULL;
work_item->object.util = NULL;
}
free(nodes);
}