From: Junio C Hamano <junkio@cox.net>
To: "Sean" <seanlkml@sympatico.ca>
Cc: "Junio C Hamano" <junkio@cox.net>,
"Linus Torvalds" <torvalds@osdl.org>,
git@vger.kernel.org
Subject: Re: [PATCH] Introduce SHA1_FILE_DIRECTORIES
Date: Sat, 07 May 2005 12:51:04 -0700 [thread overview]
Message-ID: <7vacn6ak7r.fsf@assigned-by-dhcp.cox.net> (raw)
In-Reply-To: <7vbr7nbl89.fsf@assigned-by-dhcp.cox.net> (Junio C. Hamano's message of "Fri, 06 May 2005 23:31:34 -0700")
>>>>> "JCH" == Junio C Hamano <junkio@cox.net> writes:
>>>>> "S" == Sean <seanlkml@sympatico.ca> writes:
S> Perhaps I'm just missing something in your code,...
JCH> Thankfully I think Linus had rejected this part in the series.
JCH> I'll fix it up.
Here is the fixed one. The previous one was ugly and
inconvenient to use (thanks for noticing, Sean).
I'll keep it in the git-jc repository until Linus returns.
------------
Author: Junio C Hamano <junkio@cox.net>
Date: Sat May 7 00:38:04 2005 -0700
Introduce SHA1_FILE_DIRECTORIES to support multiple object databases.
SHA1_FILE_DIRECTORIES environment variable is a colon separated paths
used when looking for SHA1 files not found in the usual place for
reading. Creating a new SHA1 file does not use this alternate object
database location mechanism. This is useful to archive older, rarely
used objects into separate directories.
Signed-off-by: Junio C Hamano <junkio@cox.net>
--- a/cache.h
+++ b/cache.h
@@ -101,6 +101,7 @@ unsigned int active_nr, active_alloc, ac
#define DB_ENVIRONMENT "SHA1_FILE_DIRECTORY"
#define DEFAULT_DB_ENVIRONMENT ".git/objects"
+#define ALTERNATE_DB_ENVIRONMENT "SHA1_FILE_DIRECTORIES"
#define get_object_directory() (getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT)
--- a/fsck-cache.c
+++ b/fsck-cache.c
@@ -306,7 +306,7 @@ int main(int argc, char **argv)
usage("fsck-cache [--tags] [[--unreachable] [--cache] <head-sha1>*]");
}
- sha1_dir = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
+ sha1_dir = get_object_directory();
for (i = 0; i < 256; i++) {
static char dir[4096];
sprintf(dir, "%s/%02x", sha1_dir, i);
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -100,18 +100,34 @@ char * sha1_to_hex(const unsigned char *
return buffer;
}
+static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
+{
+ int i;
+ for (i = 0; i < 20; i++) {
+ static char hex[] = "0123456789abcdef";
+ unsigned int val = sha1[i];
+ char *pos = pathbuf + i*2 + (i > 0);
+ *pos++ = hex[val >> 4];
+ *pos = hex[val & 0xf];
+ }
+}
+
/*
* NOTE! This returns a statically allocated buffer, so you have to be
* careful about using it. Do a "strdup()" if you need to save the
* filename.
+ *
+ * Also note that this returns the location for creating. Reading
+ * SHA1 file can happen from any alternate directory listed in the
+ * SHA1_FILE_DIRECTORIES environment variable if it is not found in
+ * the primary object database.
*/
char *sha1_file_name(const unsigned char *sha1)
{
- int i;
static char *name, *base;
if (!base) {
- char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
+ char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
memcpy(base, sha1_file_directory, len);
@@ -120,16 +136,74 @@ char *sha1_file_name(const unsigned char
base[len+3] = '/';
name = base + len + 1;
}
- for (i = 0; i < 20; i++) {
- static char hex[] = "0123456789abcdef";
- unsigned int val = sha1[i];
- char *pos = name + i*2 + (i > 0);
- *pos++ = hex[val >> 4];
- *pos = hex[val & 0xf];
- }
+ fill_sha1_path(name, sha1);
return base;
}
+static struct alternate_object_database
+{
+ char *base;
+ char *name;
+} *alt_odb;
+
+static void prepare_alt_odb(void)
+{
+ int pass, totlen, i;
+ void *buf;
+ const char *cp, *last;
+ char *op = 0;
+ const char *alt = getenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
+
+ for (totlen = pass = 0; pass < 2; pass++) {
+ last = alt;
+ i = 0;
+ do {
+ cp = strchr(last, ':') ? : last + strlen(last);
+ if (last != cp) {
+ /* 43 = 40-byte + 2 '/' + terminating NUL */
+ int pfxlen = cp - last;
+ int entlen = pfxlen + 43;
+ if (pass == 0)
+ totlen += entlen;
+ else {
+ alt_odb[i].base = op;
+ alt_odb[i].name = op + pfxlen + 1;
+ memcpy(op, last, pfxlen);
+ op[pfxlen] = op[pfxlen + 3] = '/';
+ op[entlen-1] = 0;
+ op += entlen;
+ }
+ i++;
+ }
+ while (*cp && *cp == ':')
+ cp++;
+ last = cp;
+ } while (*cp);
+ if (pass)
+ break;
+ alt_odb = buf = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
+ alt_odb[i].base = alt_odb[i].name = 0;
+ op = (char*)(&alt_odb[i+1]);
+ }
+}
+
+static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
+{
+ int i;
+ char *name = sha1_file_name(sha1);
+
+ if (!stat(name, st))
+ return name;
+ if (!alt_odb)
+ prepare_alt_odb();
+ for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
+ fill_sha1_path(name, sha1);
+ if (!stat(alt_odb[i].base, st))
+ return alt_odb[i].base;
+ }
+ return NULL;
+}
+
int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size, const char *type)
{
char header[100];
@@ -145,10 +219,15 @@ int check_sha1_signature(unsigned char *
void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
{
- char *filename = sha1_file_name(sha1);
struct stat st;
void *map;
int fd;
+ char *filename = find_sha1_file(sha1, &st);
+
+ if (!filename) {
+ error("cannot map sha1 file %s", sha1_to_hex(sha1));
+ return NULL;
+ }
fd = open(filename, O_RDONLY | sha1_file_open_flag);
if (fd < 0) {
@@ -167,10 +246,6 @@ void *map_sha1_file(const unsigned char
/* If it failed once, it will probably fail again. Stop using O_NOATIME */
sha1_file_open_flag = 0;
}
- if (fstat(fd, &st) < 0) {
- close(fd);
- return NULL;
- }
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (-1 == (int)(long)map)
@@ -315,6 +390,7 @@ int write_sha1_file(char *buf, unsigned
}
snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
+
fd = mkstemp(tmpfile);
if (fd < 0) {
fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
@@ -442,12 +518,8 @@ int write_sha1_from_fd(const unsigned ch
int has_sha1_file(const unsigned char *sha1)
{
- char *filename = sha1_file_name(sha1);
struct stat st;
-
- if (!stat(filename, &st))
- return 1;
- return 0;
+ return !!find_sha1_file(sha1, &st);
}
int index_fd(unsigned char *sha1, int fd, struct stat *st)
next prev parent reply other threads:[~2005-05-07 19:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-06 23:35 [PATCH] Introduce SHA1_FILE_DIRECTORIES Junio C Hamano
2005-05-07 0:20 ` Sean
2005-05-07 0:24 ` Junio C Hamano
2005-05-07 0:32 ` Sean
2005-05-07 6:31 ` Junio C Hamano
2005-05-07 19:51 ` Junio C Hamano [this message]
2005-05-09 13:33 ` H. Peter Anvin
2005-05-09 16:38 ` Junio C Hamano
2005-05-09 16:41 ` Sean
2005-05-09 18:03 ` H. Peter Anvin
2005-05-09 18:50 ` Junio C Hamano
2005-05-09 20:05 ` [RFC] Renaming environment variables Junio C Hamano
2005-05-09 20:15 ` Thomas Glanzmann
2005-05-10 0:32 ` Petr Baudis
2005-05-09 21:04 ` Sean
2005-05-09 23:08 ` Daniel Barkalow
2005-05-10 0:09 ` Junio C Hamano
2005-05-10 0:13 ` Petr Baudis
2005-05-10 0:22 ` Junio C Hamano
2005-05-10 0:27 ` Petr Baudis
2005-05-10 0:38 ` Daniel Barkalow
2005-05-10 0:44 ` Petr Baudis
2005-05-10 0:53 ` Daniel Barkalow
2005-05-10 5:45 ` Junio C Hamano
2005-05-10 6:25 ` Introducing GIT_DIR environment variable Junio C Hamano
2005-05-10 23:39 ` Alex Riesen
2005-05-10 2:16 ` [RFC] Renaming environment variables Junio C Hamano
2005-05-10 3:23 ` Daniel Barkalow
2005-05-10 0:25 ` Petr Baudis
2005-05-10 1:02 ` Junio C Hamano
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