Update tutorial.

diff --git a/pack-objects.c b/pack-objects.c
index feee5600b9c362ad1436db64e3624f646f064fc3..3d622787cc554eb2936995441e4591ec1986bded 100644 (file)
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -5,7 +5,7 @@
 #include "pack.h"
 #include "csum-file.h"
 
-static const char pack_usage[] = "git-pack-objects [--window=N] [--depth=N] {--stdout | base-name} < object-list";
+static const char pack_usage[] = "git-pack-objects [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 
 struct object_entry {
        unsigned char sha1[20];
@@ -18,6 +18,9 @@ struct object_entry {
        struct object_entry *delta;
 };
 
+static unsigned char object_list_sha1[20];
+static int non_empty = 0;
+static int incremental = 0;
 static struct object_entry **sorted_by_sha, **sorted_by_type;
 static struct object_entry *objects = NULL;
 static int nr_objects = 0, nr_alloc = 0;
@@ -34,7 +37,7 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
        if (!otherbuf)
                die("unable to read %s", sha1_to_hex(entry->delta->sha1));
         delta_buf = diff_delta(otherbuf, othersize,
-                              buf, size, &delta_size, ~0UL);
+                              buf, size, &delta_size, 0);
         if (!delta_buf || delta_size != entry->delta_size)
                die("delta size changed");
         free(buf);
@@ -51,32 +54,19 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
  */
 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 {
-       int n = 1, i;
+       int n = 1;
        unsigned char c;
 
        if (type < OBJ_COMMIT || type > OBJ_DELTA)
                die("bad type %d", type);
 
-       /*
-        * Shift the size up by 7 bits at a time,
-        * until you get bits in the "high four".
-        * That will be our beginning. We'll have
-        * four size bits in 28..31, then groups
-        * of seven in 21..27, 14..20, 7..13 and
-        * finally 0..6.
-        */
-       if (size) {
-               n = 5;
-               while (!(size & 0xfe000000)) {
-                       size <<= 7;
-                       n--;
-               }
-       }
-       c = (type << 4) | (size >> 28);
-       for (i = 1; i < n; i++) {
+       c = (type << 4) | (size & 15);
+       size >>= 4;
+       while (size) {
                *hdr++ = c | 0x80;
-               c = (size >> 21) & 0x7f;
-               size <<= 7;
+               c = size & 0x7f;
+               size >>= 7;
+               n++;
        }
        *hdr = c;
        return n;
@@ -146,9 +136,9 @@ static void write_pack_file(void)
        if (!base_name)
                f = sha1fd(1, "<stdout>");
        else
-               f = sha1create("%s.%s", base_name, "pack");
+               f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "pack");
        hdr.hdr_signature = htonl(PACK_SIGNATURE);
-       hdr.hdr_version = htonl(1);
+       hdr.hdr_version = htonl(PACK_VERSION);
        hdr.hdr_entries = htonl(nr_objects);
        sha1write(f, &hdr, sizeof(hdr));
        offset = sizeof(hdr);
@@ -163,7 +153,7 @@ static void write_pack_file(void)
 static void write_index_file(void)
 {
        int i;
-       struct sha1file *f = sha1create("%s.%s", base_name, "idx");
+       struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx");
        struct object_entry **list = sorted_by_sha;
        struct object_entry **last = list + nr_objects;
        unsigned int array[256];
@@ -200,11 +190,14 @@ static void write_index_file(void)
        sha1close(f, NULL, 1);
 }
 
-static void add_object_entry(unsigned char *sha1, unsigned int hash)
+static int add_object_entry(unsigned char *sha1, unsigned int hash)
 {
        unsigned int idx = nr_objects;
        struct object_entry *entry;
 
+       if (incremental && has_sha1_pack(sha1))
+               return 0;
+
        if (idx >= nr_alloc) {
                unsigned int needed = (idx + 1024) * 3 / 2;
                objects = xrealloc(objects, needed * sizeof(*entry));
@@ -215,6 +208,7 @@ static void add_object_entry(unsigned char *sha1, unsigned int hash)
        memcpy(entry->sha1, sha1, 20);
        entry->hash = hash;
        nr_objects = idx+1;
+       return 1;
 }
 
 static void check_object(struct object_entry *entry)
@@ -388,10 +382,15 @@ static void find_deltas(struct object_entry **list, int window, int depth)
                if (idx >= window)
                        idx = 0;
        }
+
+       for (i = 0; i < window; ++i)
+               free(array[i].data);
+       free(array);
 }
 
 int main(int argc, char **argv)
 {
+       SHA_CTX ctx;
        char line[PATH_MAX + 20];
        int window = 10, depth = 10, pack_to_stdout = 0;
        int i;
@@ -400,6 +399,14 @@ int main(int argc, char **argv)
                const char *arg = argv[i];
 
                if (*arg == '-') {
+                       if (!strcmp("--non-empty", arg)) {
+                               non_empty = 1;
+                               continue;
+                       }
+                       if (!strcmp("--incremental", arg)) {
+                               incremental = 1;
+                               continue;
+                       }
                        if (!strncmp("--window=", arg, 9)) {
                                char *end;
                                window = strtoul(arg+9, &end, 0);
@@ -428,6 +435,7 @@ int main(int argc, char **argv)
        if (pack_to_stdout != !base_name)
                usage(pack_usage);
 
+       SHA1_Init(&ctx);
        while (fgets(line, sizeof(line), stdin) != NULL) {
                unsigned int hash;
                char *p;
@@ -443,8 +451,12 @@ int main(int argc, char **argv)
                                continue;
                        hash = hash * 11 + c;
                }
-               add_object_entry(sha1, hash);
+               if (add_object_entry(sha1, hash))
+                       SHA1_Update(&ctx, sha1, 20);
        }
+       SHA1_Final(object_list_sha1, &ctx);
+       if (non_empty && !nr_objects)
+               return 0;
        get_object_details();
 
        fprintf(stderr, "Packing %d objects\n", nr_objects);
@@ -455,7 +467,9 @@ int main(int argc, char **argv)
                find_deltas(sorted_by_type, window+1, depth);
 
        write_pack_file();
-       if (!pack_to_stdout)
+       if (!pack_to_stdout) {
                write_index_file();
+               puts(sha1_to_hex(object_list_sha1));
+       }
        return 0;
 }