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vcs-svn: implement perfect hash for node-prop keys

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Instead of interning property names and comparing their string_pool
keys, look them up in a table by string length, which should be about
as fast.

This is a small step towards removing dependence on string_pool.

Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
This commit is contained in:
David Barr 2010-12-13 19:13:24 +11:00 committed by Jonathan Nieder
parent c9d1c8ba05
commit 044ad2906a
1 changed files with 43 additions and 19 deletions
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62
vcs-svn/svndump.c
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@ -14,6 +14,12 @@
#include "obj_pool.h"
#include "string_pool.h"
/*
* Compare start of string to literal of equal length;
* must be guarded by length test.
*/
#define constcmp(s, ref) memcmp(s, ref, sizeof(ref) - 1)
#define NODEACT_REPLACE 4
#define NODEACT_DELETE 3
#define NODEACT_ADD 2
@ -58,8 +64,7 @@ static struct {
} dump_ctx;
static struct {
uint32_t svn_log, svn_author, svn_date, svn_executable, svn_special, uuid,
revision_number, node_path, node_kind, node_action,
uint32_t uuid, revision_number, node_path, node_kind, node_action,
node_copyfrom_path, node_copyfrom_rev, text_content_length,
prop_content_length, content_length, svn_fs_dump_format_version,
/* version 3 format */
@ -96,11 +101,6 @@ static void reset_dump_ctx(uint32_t url)
static void init_keys(void)
{
keys.svn_log = pool_intern("svn:log");
keys.svn_author = pool_intern("svn:author");
keys.svn_date = pool_intern("svn:date");
keys.svn_executable = pool_intern("svn:executable");
keys.svn_special = pool_intern("svn:special");
keys.uuid = pool_intern("UUID");
keys.revision_number = pool_intern("Revision-number");
keys.node_path = pool_intern("Node-path");
@ -117,22 +117,43 @@ static void init_keys(void)
keys.prop_delta = pool_intern("Prop-delta");
}
static void handle_property(uint32_t key, const char *val, uint32_t len,
static void handle_property(const struct strbuf *key_buf,
const char *val, uint32_t len,
uint32_t *type_set)
{
if (key == keys.svn_log) {
const char *key = key_buf->buf;
size_t keylen = key_buf->len;
switch (keylen + 1) {
case sizeof("svn:log"):
if (constcmp(key, "svn:log"))
break;
if (!val)
die("invalid dump: unsets svn:log");
/* Value length excludes terminating nul. */
rev_ctx.log = log_copy(len + 1, val);
} else if (key == keys.svn_author) {
break;
case sizeof("svn:author"):
if (constcmp(key, "svn:author"))
break;
rev_ctx.author = pool_intern(val);
} else if (key == keys.svn_date) {
break;
case sizeof("svn:date"):
if (constcmp(key, "svn:date"))
break;
if (!val)
die("invalid dump: unsets svn:date");
if (parse_date_basic(val, &rev_ctx.timestamp, NULL))
warning("invalid timestamp: %s", val);
} else if (key == keys.svn_executable || key == keys.svn_special) {
break;
case sizeof("svn:executable"):
case sizeof("svn:special"):
if (keylen == strlen("svn:executable") &&
constcmp(key, "svn:executable"))
break;
if (keylen == strlen("svn:special") &&
constcmp(key, "svn:special"))
break;
if (*type_set) {
if (!val)
return;
@ -143,7 +164,7 @@ static void handle_property(uint32_t key, const char *val, uint32_t len,
return;
}
*type_set = 1;
node_ctx.type = key == keys.svn_executable ?
node_ctx.type = keylen == strlen("svn:executable") ?
REPO_MODE_EXE :
REPO_MODE_LNK;
}
@ -158,7 +179,7 @@ static void die_short_read(void)
static void read_props(void)
{
uint32_t key = ~0;
static struct strbuf key = STRBUF_INIT;
const char *t;
/*
* NEEDSWORK: to support simple mode changes like
@ -195,16 +216,19 @@ static void read_props(void)
switch (type) {
case 'K':
key = pool_intern(val);
continue;
case 'D':
key = pool_intern(val);
strbuf_reset(&key);
if (val)
strbuf_add(&key, val, len);
if (type == 'K')
continue;
assert(type == 'D');
val = NULL;
len = 0;
/* fall through */
case 'V':
handle_property(key, val, len, &type_set);
key = ~0;
handle_property(&key, val, len, &type_set);
strbuf_reset(&key);
continue;
default:
die("invalid property line: %s\n", t);