From: David Barr Date: Mon, 13 Dec 2010 08:13:24 +0000 (+1100) Subject: vcs-svn: implement perfect hash for node-prop keys X-Git-Tag: v1.7.5-rc0~3^2~8^2~2 X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=044ad2906a5e4b805bc8c8d121466d8ff94ecbfb;p=git.git vcs-svn: implement perfect hash for node-prop keys 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 Signed-off-by: Jonathan Nieder --- diff --git a/vcs-svn/svndump.c b/vcs-svn/svndump.c index 15f822ea8..322d1cd30 100644 --- a/vcs-svn/svndump.c +++ b/vcs-svn/svndump.c @@ -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);