Refactored fast-import's internals for future additions.

Too many globals variables were being used not not enough
code was resuable to process trees and commits so this is
a simple refactoring of the existing blob processing code
to get into a state that will be easier to handle trees
and commits in.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/fast-import.c b/fast-import.c
index 3856c87c4e03a91ad0cea36e5a9d00676e80833a..8b4be28f606b812e27d513e7907f3e8032a96056 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -18,22 +18,34 @@ struct object_entry_block
        struct object_entry_block *next_block;
        struct object_entry *next_free;
        struct object_entry *end;
-       struct object_entry entries[0];
+       struct object_entry entries[FLEX_ARRAY]; /* more */
 };
 
+struct last_object
+{
+       void *data;
+       unsigned long len;
+       int depth;
+       unsigned char sha1[20];
+};
+
+/* Stats and misc. counters. */
 static int max_depth = 10;
 static unsigned long alloc_count;
 static unsigned long object_count;
 static unsigned long duplicate_count;
-static unsigned long packoff;
-static int packfd;
-static int current_depth;
-static void *lastdat;
-static unsigned long lastdatlen;
-static unsigned char lastsha1[20];
-static unsigned char packsha1[20];
-struct object_entry *object_table[1 << 16];
+
+/* The .pack file */
+static int pack_fd;
+static unsigned long pack_offset;
+static unsigned char pack_sha1[20];
+
+/* Table of objects we've written. */
 struct object_entry_block *blocks;
+struct object_entry *object_table[1 << 16];
+
+/* Our last blob */
+struct last_object last_blob;
 
 static void alloc_objects(int cnt)
 {
@@ -115,7 +127,10 @@ static ssize_t ywrite(int fd, void *buffer, size_t length)
        return ret;
 }
 
-static unsigned long encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
+static unsigned long encode_header(
+       enum object_type type,
+       unsigned long size,
+       unsigned char *hdr)
 {
        int n = 1;
        unsigned char c;
@@ -135,41 +150,62 @@ static unsigned long encode_header(enum object_type type, unsigned long size, un
        return n;
 }
 
-static void write_blob(void *dat, unsigned long datlen)
+static int store_object(
+       enum object_type type,
+       void *dat,
+       unsigned long datlen,
+       struct last_object *last)
 {
-       z_stream s;
        void *out, *delta;
-       unsigned char hdr[64];
+       struct object_entry *e;
+       unsigned char hdr[96];
+       unsigned char sha1[20];
        unsigned long hdrlen, deltalen;
+       SHA_CTX c;
+       z_stream s;
+
+       hdrlen = sprintf((char*)hdr,"%s %lu",type_names[type],datlen) + 1;
+       SHA1_Init(&c);
+       SHA1_Update(&c, hdr, hdrlen);
+       SHA1_Update(&c, dat, datlen);
+       SHA1_Final(sha1, &c);
+
+       e = insert_object(sha1);
+       if (e->offset) {
+               duplicate_count++;
+               return 0;
+       }
+       e->offset = pack_offset;
+       object_count++;
 
-       if (lastdat && current_depth < max_depth) {
-               delta = diff_delta(lastdat, lastdatlen,
+       if (last->data && last->depth < max_depth)
+               delta = diff_delta(last->data, last->len,
                        dat, datlen,
                        &deltalen, 0);
-       } else
+       else
                delta = 0;
 
        memset(&s, 0, sizeof(s));
        deflateInit(&s, zlib_compression_level);
 
        if (delta) {
-               current_depth++;
+               last->depth++;
                s.next_in = delta;
                s.avail_in = deltalen;
                hdrlen = encode_header(OBJ_DELTA, deltalen, hdr);
-               if (ywrite(packfd, hdr, hdrlen) != hdrlen)
+               if (ywrite(pack_fd, hdr, hdrlen) != hdrlen)
                        die("Can't write object header: %s", strerror(errno));
-               if (ywrite(packfd, lastsha1, sizeof(lastsha1)) != sizeof(lastsha1))
+               if (ywrite(pack_fd, last->sha1, sizeof(sha1)) != sizeof(sha1))
                        die("Can't write object base: %s", strerror(errno));
-               packoff += hdrlen + sizeof(lastsha1);
+               pack_offset += hdrlen + sizeof(sha1);
        } else {
-               current_depth = 0;
+               last->depth = 0;
                s.next_in = dat;
                s.avail_in = datlen;
-               hdrlen = encode_header(OBJ_BLOB, datlen, hdr);
-               if (ywrite(packfd, hdr, hdrlen) != hdrlen)
+               hdrlen = encode_header(type, datlen, hdr);
+               if (ywrite(pack_fd, hdr, hdrlen) != hdrlen)
                        die("Can't write object header: %s", strerror(errno));
-               packoff += hdrlen;
+               pack_offset += hdrlen;
        }
 
        s.avail_out = deflateBound(&s, s.avail_in);
@@ -178,13 +214,19 @@ static void write_blob(void *dat, unsigned long datlen)
                /* nothing */;
        deflateEnd(&s);
 
-       if (ywrite(packfd, out, s.total_out) != s.total_out)
+       if (ywrite(pack_fd, out, s.total_out) != s.total_out)
                die("Failed writing compressed data %s", strerror(errno));
-       packoff += s.total_out;
+       pack_offset += s.total_out;
 
        free(out);
        if (delta)
                free(delta);
+       if (last->data)
+               free(last->data);
+       last->data = dat;
+       last->len = datlen;
+       memcpy(last->sha1, sha1, sizeof(sha1));
+       return 1;
 }
 
 static void init_pack_header()
@@ -195,13 +237,13 @@ static void init_pack_header()
 
        version = htonl(version);
 
-       if (ywrite(packfd, (char*)magic, 4) != 4)
+       if (ywrite(pack_fd, (char*)magic, 4) != 4)
                die("Can't write pack magic: %s", strerror(errno));
-       if (ywrite(packfd, &version, 4) != 4)
+       if (ywrite(pack_fd, &version, 4) != 4)
                die("Can't write pack version: %s", strerror(errno));
-       if (ywrite(packfd, &zero, 4) != 4)
+       if (ywrite(pack_fd, &zero, 4) != 4)
                die("Can't write 0 object count: %s", strerror(errno));
-       packoff = 4 * 3;
+       pack_offset = 4 * 3;
 }
 
 static void fixup_header_footer()
@@ -212,30 +254,30 @@ static void fixup_header_footer()
        char *buf;
        size_t n;
 
-       if (lseek(packfd, 0, SEEK_SET) != 0)
+       if (lseek(pack_fd, 0, SEEK_SET) != 0)
                die("Failed seeking to start: %s", strerror(errno));
 
        SHA1_Init(&c);
-       if (yread(packfd, hdr, 8) != 8)
+       if (yread(pack_fd, hdr, 8) != 8)
                die("Failed reading header: %s", strerror(errno));
        SHA1_Update(&c, hdr, 8);
 
        cnt = htonl(object_count);
        SHA1_Update(&c, &cnt, 4);
-       if (ywrite(packfd, &cnt, 4) != 4)
+       if (ywrite(pack_fd, &cnt, 4) != 4)
                die("Failed writing object count: %s", strerror(errno));
 
        buf = xmalloc(128 * 1024);
        for (;;) {
-               n = xread(packfd, buf, 128 * 1024);
+               n = xread(pack_fd, buf, 128 * 1024);
                if (n <= 0)
                        break;
                SHA1_Update(&c, buf, n);
        }
        free(buf);
 
-       SHA1_Final(packsha1, &c);
-       if (ywrite(packfd, packsha1, sizeof(packsha1)) != sizeof(packsha1))
+       SHA1_Final(pack_sha1, &c);
+       if (ywrite(pack_fd, pack_sha1, sizeof(pack_sha1)) != sizeof(pack_sha1))
                die("Failed writing pack checksum: %s", strerror(errno));
 }
 
@@ -284,7 +326,7 @@ static void write_index(const char *idx_name)
                sha1write(f, &offset, 4);
                sha1write(f, (*c)->sha1, sizeof((*c)->sha1));
        }
-       sha1write(f, packsha1, sizeof(packsha1));
+       sha1write(f, pack_sha1, sizeof(pack_sha1));
        sha1close(f, NULL, 1);
        free(idx);
 }
@@ -301,53 +343,28 @@ int main(int argc, const char **argv)
        idx_name = xmalloc(strlen(base_name) + 5);
        sprintf(idx_name, "%s.idx", base_name);
 
-       packfd = open(pack_name, O_RDWR|O_CREAT|O_EXCL, 0666);
-       if (packfd < 0)
+       pack_fd = open(pack_name, O_RDWR|O_CREAT|O_EXCL, 0666);
+       if (pack_fd < 0)
                die("Can't create pack file %s: %s", pack_name, strerror(errno));
 
        alloc_objects(est_obj_cnt);
        init_pack_header();
        for (;;) {
                unsigned long datlen;
-               int hdrlen;
                void *dat;
-               char hdr[128];
-               unsigned char sha1[20];
-               SHA_CTX c;
-               struct object_entry *e;
 
                if (yread(0, &datlen, 4) != 4)
-
                        break;
 
                dat = xmalloc(datlen);
                if (yread(0, dat, datlen) != datlen)
                        break;
 
-               hdrlen = sprintf(hdr, "blob %lu", datlen) + 1;
-               SHA1_Init(&c);
-               SHA1_Update(&c, hdr, hdrlen);
-               SHA1_Update(&c, dat, datlen);
-               SHA1_Final(sha1, &c);
-
-               e = insert_object(sha1);
-               if (!e->offset) {
-                       e->offset = packoff;
-                       write_blob(dat, datlen);
-                       object_count++;
-
-                       if (lastdat)
-                               free(lastdat);
-                       lastdat = dat;
-                       lastdatlen = datlen;
-                       memcpy(lastsha1, sha1, sizeof(sha1));
-               } else {
-                       duplicate_count++;
+               if (!store_object(OBJ_BLOB, dat, datlen, &last_blob))
                        free(dat);
-               }
        }
        fixup_header_footer();
-       close(packfd);
+       close(pack_fd);
        write_index(idx_name);
 
        fprintf(stderr, "%lu objects, %lu duplicates, %lu allocated (%lu overflow)\n",