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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-07 22:13:13 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-07 22:13:13 (GMT)
commite83c5163316f89bfbde7d9ab23ca2e25604af290 (patch)
tree2b5bfdf7798569e0b59b16eb9602d5fa572d6038 /read-cache.c
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Initial revision of "git", the information manager from hell
Diffstat (limited to 'read-cache.c')
-rw-r--r--read-cache.c259
1 files changed, 259 insertions, 0 deletions
diff --git a/read-cache.c b/read-cache.c
new file mode 100644
index 0000000..c924a6e
--- /dev/null
+++ b/read-cache.c
@@ -0,0 +1,259 @@
+#include "cache.h"
+
+const char *sha1_file_directory = NULL;
+struct cache_entry **active_cache = NULL;
+unsigned int active_nr = 0, active_alloc = 0;
+
+void usage(const char *err)
+{
+ fprintf(stderr, "read-tree: %s\n", err);
+ exit(1);
+}
+
+static unsigned hexval(char c)
+{
+ if (c >= '0' && c <= '9')
+ return c - '0';
+ if (c >= 'a' && c <= 'f')
+ return c - 'a' + 10;
+ if (c >= 'A' && c <= 'F')
+ return c - 'A' + 10;
+ return ~0;
+}
+
+int get_sha1_hex(char *hex, unsigned char *sha1)
+{
+ int i;
+ for (i = 0; i < 20; i++) {
+ unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
+ if (val & ~0xff)
+ return -1;
+ *sha1++ = val;
+ hex += 2;
+ }
+ return 0;
+}
+
+char * sha1_to_hex(unsigned char *sha1)
+{
+ static char buffer[50];
+ static const char hex[] = "0123456789abcdef";
+ char *buf = buffer;
+ int i;
+
+ for (i = 0; i < 20; i++) {
+ unsigned int val = *sha1++;
+ *buf++ = hex[val >> 4];
+ *buf++ = hex[val & 0xf];
+ }
+ return buffer;
+}
+
+/*
+ * 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.
+ */
+char *sha1_file_name(unsigned char *sha1)
+{
+ int i;
+ static char *name, *base;
+
+ if (!base) {
+ char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
+ int len = strlen(sha1_file_directory);
+ base = malloc(len + 60);
+ memcpy(base, sha1_file_directory, len);
+ memset(base+len, 0, 60);
+ base[len] = '/';
+ 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];
+ }
+ return base;
+}
+
+void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
+{
+ z_stream stream;
+ char buffer[8192];
+ struct stat st;
+ int i, fd, ret, bytes;
+ void *map, *buf;
+ char *filename = sha1_file_name(sha1);
+
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ perror(filename);
+ return NULL;
+ }
+ 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)
+ return NULL;
+
+ /* Get the data stream */
+ memset(&stream, 0, sizeof(stream));
+ stream.next_in = map;
+ stream.avail_in = st.st_size;
+ stream.next_out = buffer;
+ stream.avail_out = sizeof(buffer);
+
+ inflateInit(&stream);
+ ret = inflate(&stream, 0);
+ if (sscanf(buffer, "%10s %lu", type, size) != 2)
+ return NULL;
+ bytes = strlen(buffer) + 1;
+ buf = malloc(*size);
+ if (!buf)
+ return NULL;
+
+ memcpy(buf, buffer + bytes, stream.total_out - bytes);
+ bytes = stream.total_out - bytes;
+ if (bytes < *size && ret == Z_OK) {
+ stream.next_out = buf + bytes;
+ stream.avail_out = *size - bytes;
+ while (inflate(&stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ }
+ inflateEnd(&stream);
+ return buf;
+}
+
+int write_sha1_file(char *buf, unsigned len)
+{
+ int size;
+ char *compressed;
+ z_stream stream;
+ unsigned char sha1[20];
+ SHA_CTX c;
+
+ /* Set it up */
+ memset(&stream, 0, sizeof(stream));
+ deflateInit(&stream, Z_BEST_COMPRESSION);
+ size = deflateBound(&stream, len);
+ compressed = malloc(size);
+
+ /* Compress it */
+ stream.next_in = buf;
+ stream.avail_in = len;
+ stream.next_out = compressed;
+ stream.avail_out = size;
+ while (deflate(&stream, Z_FINISH) == Z_OK)
+ /* nothing */;
+ deflateEnd(&stream);
+ size = stream.total_out;
+
+ /* Sha1.. */
+ SHA1_Init(&c);
+ SHA1_Update(&c, compressed, size);
+ SHA1_Final(sha1, &c);
+
+ if (write_sha1_buffer(sha1, compressed, size) < 0)
+ return -1;
+ printf("%s\n", sha1_to_hex(sha1));
+ return 0;
+}
+
+int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
+{
+ char *filename = sha1_file_name(sha1);
+ int i, fd;
+
+ fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
+ if (fd < 0)
+ return (errno == EEXIST) ? 0 : -1;
+ write(fd, buf, size);
+ close(fd);
+ return 0;
+}
+
+static int error(const char * string)
+{
+ fprintf(stderr, "error: %s\n", string);
+ return -1;
+}
+
+static int verify_hdr(struct cache_header *hdr, unsigned long size)
+{
+ SHA_CTX c;
+ unsigned char sha1[20];
+
+ if (hdr->signature != CACHE_SIGNATURE)
+ return error("bad signature");
+ if (hdr->version != 1)
+ return error("bad version");
+ SHA1_Init(&c);
+ SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
+ SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
+ SHA1_Final(sha1, &c);
+ if (memcmp(sha1, hdr->sha1, 20))
+ return error("bad header sha1");
+ return 0;
+}
+
+int read_cache(void)
+{
+ int fd, i;
+ struct stat st;
+ unsigned long size, offset;
+ void *map;
+ struct cache_header *hdr;
+
+ errno = EBUSY;
+ if (active_cache)
+ return error("more than one cachefile");
+ errno = ENOENT;
+ sha1_file_directory = getenv(DB_ENVIRONMENT);
+ if (!sha1_file_directory)
+ sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
+ if (access(sha1_file_directory, X_OK) < 0)
+ return error("no access to SHA1 file directory");
+ fd = open(".dircache/index", O_RDONLY);
+ if (fd < 0)
+ return (errno == ENOENT) ? 0 : error("open failed");
+
+ map = (void *)-1;
+ if (!fstat(fd, &st)) {
+ map = NULL;
+ size = st.st_size;
+ errno = EINVAL;
+ if (size > sizeof(struct cache_header))
+ map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ }
+ close(fd);
+ if (-1 == (int)(long)map)
+ return error("mmap failed");
+
+ hdr = map;
+ if (verify_hdr(hdr, size) < 0)
+ goto unmap;
+
+ active_nr = hdr->entries;
+ active_alloc = alloc_nr(active_nr);
+ active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
+
+ offset = sizeof(*hdr);
+ for (i = 0; i < hdr->entries; i++) {
+ struct cache_entry *ce = map + offset;
+ offset = offset + ce_size(ce);
+ active_cache[i] = ce;
+ }
+ return active_nr;
+
+unmap:
+ munmap(map, size);
+ errno = EINVAL;
+ return error("verify header failed");
+}
+