compat: Add simplified merge sort implementation from glibc
[gitweb.git] / fast-import.c
index 5e83296bf49f9b41b019185539cbd4ec1bf94513..a523b171e22f83d6a656b372cf20afe52d27d1b2 100644 (file)
@@ -149,7 +149,6 @@ Format of STDIN stream:
 #include "pack.h"
 #include "refs.h"
 #include "csum-file.h"
-#include "strbuf.h"
 #include "quote.h"
 
 #define PACK_ID_BITS 16
@@ -186,11 +185,10 @@ struct mark_set
 
 struct last_object
 {
-       void *data;
-       unsigned long len;
+       struct strbuf data;
        uint32_t offset;
        unsigned int depth;
-       unsigned no_free:1;
+       unsigned no_swap : 1;
 };
 
 struct mem_pool
@@ -198,7 +196,7 @@ struct mem_pool
        struct mem_pool *next_pool;
        char *next_free;
        char *end;
-       char space[FLEX_ARRAY]; /* more */
+       uintmax_t space[FLEX_ARRAY]; /* more */
 };
 
 struct atom_str
@@ -254,12 +252,6 @@ struct tag
        unsigned char sha1[20];
 };
 
-struct dbuf
-{
-       void *buffer;
-       size_t capacity;
-};
-
 struct hash_list
 {
        struct hash_list *next;
@@ -283,6 +275,8 @@ struct recent_command
 static unsigned long max_depth = 10;
 static off_t max_packsize = (1LL << 32) - 1;
 static int force_update;
+static int pack_compression_level = Z_DEFAULT_COMPRESSION;
+static int pack_compression_seen;
 
 /* Stats and misc. counters */
 static uintmax_t alloc_count;
@@ -320,15 +314,15 @@ static struct mark_set *marks;
 static const char* mark_file;
 
 /* Our last blob */
-static struct last_object last_blob;
+static struct last_object last_blob = { STRBUF_INIT, 0, 0, 0 };
 
 /* Tree management */
 static unsigned int tree_entry_alloc = 1000;
 static void *avail_tree_entry;
 static unsigned int avail_tree_table_sz = 100;
 static struct avail_tree_content **avail_tree_table;
-static struct dbuf old_tree;
-static struct dbuf new_tree;
+static struct strbuf old_tree = STRBUF_INIT;
+static struct strbuf new_tree = STRBUF_INIT;
 
 /* Branch data */
 static unsigned long max_active_branches = 5;
@@ -343,14 +337,14 @@ static struct tag *last_tag;
 
 /* Input stream parsing */
 static whenspec_type whenspec = WHENSPEC_RAW;
-static struct strbuf command_buf;
+static struct strbuf command_buf = STRBUF_INIT;
 static int unread_command_buf;
 static struct recent_command cmd_hist = {&cmd_hist, &cmd_hist, NULL};
 static struct recent_command *cmd_tail = &cmd_hist;
 static struct recent_command *rc_free;
 static unsigned int cmd_save = 100;
 static uintmax_t next_mark;
-static struct dbuf new_data;
+static struct strbuf new_data = STRBUF_INIT;
 
 static void write_branch_report(FILE *rpt, struct branch *b)
 {
@@ -542,15 +536,15 @@ static void *pool_alloc(size_t len)
                total_allocd += sizeof(struct mem_pool) + mem_pool_alloc;
                p = xmalloc(sizeof(struct mem_pool) + mem_pool_alloc);
                p->next_pool = mem_pool;
-               p->next_free = p->space;
+               p->next_free = (char *) p->space;
                p->end = p->next_free + mem_pool_alloc;
                mem_pool = p;
        }
 
        r = p->next_free;
-       /* round out to a pointer alignment */
-       if (len & (sizeof(void*) - 1))
-               len += sizeof(void*) - (len & (sizeof(void*) - 1));
+       /* round out to a 'uintmax_t' alignment */
+       if (len & (sizeof(uintmax_t) - 1))
+               len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
        p->next_free += len;
        return r;
 }
@@ -570,17 +564,6 @@ static char *pool_strdup(const char *s)
        return r;
 }
 
-static void size_dbuf(struct dbuf *b, size_t maxlen)
-{
-       if (b->buffer) {
-               if (b->capacity >= maxlen)
-                       return;
-               free(b->buffer);
-       }
-       b->capacity = ((maxlen / 1024) + 1) * 1024;
-       b->buffer = xmalloc(b->capacity);
-}
-
 static void insert_mark(uintmax_t idnum, struct object_entry *oe)
 {
        struct mark_set *s = marks;
@@ -661,8 +644,9 @@ static struct branch *new_branch(const char *name)
        if (b)
                die("Invalid attempt to create duplicate branch: %s", name);
        switch (check_ref_format(name)) {
-       case  0: break; /* its valid */
-       case -2: break; /* valid, but too few '/', allow anyway */
+       case 0: break; /* its valid */
+       case CHECK_REF_FORMAT_ONELEVEL:
+               break; /* valid, but too few '/', allow anyway */
        default:
                die("Branch name doesn't conform to GIT standards: %s", name);
        }
@@ -896,8 +880,9 @@ static char *keep_pack(char *curr_index_name)
        keep_fd = open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
        if (keep_fd < 0)
                die("cannot create keep file");
-       write(keep_fd, keep_msg, strlen(keep_msg));
-       close(keep_fd);
+       write_or_die(keep_fd, keep_msg, strlen(keep_msg));
+       if (close(keep_fd))
+               die("failed to write keep file");
 
        snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
                 get_object_directory(), sha1_to_hex(pack_data->sha1));
@@ -934,6 +919,7 @@ static void end_packfile(void)
                struct branch *b;
                struct tag *t;
 
+               close_pack_windows(pack_data);
                fixup_pack_header_footer(pack_data->pack_fd, pack_data->sha1,
                                    pack_data->pack_name, object_count);
                close(pack_data->pack_fd);
@@ -943,7 +929,6 @@ static void end_packfile(void)
                new_p = add_packed_git(idx_name, strlen(idx_name), 1);
                if (!new_p)
                        die("core git rejected index %s", idx_name);
-               new_p->windows = old_p->windows;
                all_packs[pack_id] = new_p;
                install_packed_git(new_p);
 
@@ -971,9 +956,7 @@ static void end_packfile(void)
        free(old_p);
 
        /* We can't carry a delta across packfiles. */
-       free(last_blob.data);
-       last_blob.data = NULL;
-       last_blob.len = 0;
+       strbuf_release(&last_blob.data);
        last_blob.offset = 0;
        last_blob.depth = 0;
 }
@@ -1009,8 +992,7 @@ static size_t encode_header(
 
 static int store_object(
        enum object_type type,
-       void *dat,
-       size_t datlen,
+       struct strbuf *dat,
        struct last_object *last,
        unsigned char *sha1out,
        uintmax_t mark)
@@ -1024,10 +1006,10 @@ static int store_object(
        z_stream s;
 
        hdrlen = sprintf((char*)hdr,"%s %lu", typename(type),
-               (unsigned long)datlen) + 1;
+               (unsigned long)dat->len) + 1;
        SHA1_Init(&c);
        SHA1_Update(&c, hdr, hdrlen);
-       SHA1_Update(&c, dat, datlen);
+       SHA1_Update(&c, dat->buf, dat->len);
        SHA1_Final(sha1, &c);
        if (sha1out)
                hashcpy(sha1out, sha1);
@@ -1046,11 +1028,11 @@ static int store_object(
                return 1;
        }
 
-       if (last && last->data && last->depth < max_depth) {
-               delta = diff_delta(last->data, last->len,
-                       dat, datlen,
+       if (last && last->data.buf && last->depth < max_depth) {
+               delta = diff_delta(last->data.buf, last->data.len,
+                       dat->buf, dat->len,
                        &deltalen, 0);
-               if (delta && deltalen >= datlen) {
+               if (delta && deltalen >= dat->len) {
                        free(delta);
                        delta = NULL;
                }
@@ -1058,13 +1040,13 @@ static int store_object(
                delta = NULL;
 
        memset(&s, 0, sizeof(s));
-       deflateInit(&s, zlib_compression_level);
+       deflateInit(&s, pack_compression_level);
        if (delta) {
                s.next_in = delta;
                s.avail_in = deltalen;
        } else {
-               s.next_in = dat;
-               s.avail_in = datlen;
+               s.next_in = (void *)dat->buf;
+               s.avail_in = dat->len;
        }
        s.avail_out = deflateBound(&s, s.avail_in);
        s.next_out = out = xmalloc(s.avail_out);
@@ -1086,9 +1068,9 @@ static int store_object(
                        delta = NULL;
 
                        memset(&s, 0, sizeof(s));
-                       deflateInit(&s, zlib_compression_level);
-                       s.next_in = dat;
-                       s.avail_in = datlen;
+                       deflateInit(&s, pack_compression_level);
+                       s.next_in = (void *)dat->buf;
+                       s.avail_in = dat->len;
                        s.avail_out = deflateBound(&s, s.avail_in);
                        s.next_out = out = xrealloc(out, s.avail_out);
                        while (deflate(&s, Z_FINISH) == Z_OK)
@@ -1121,7 +1103,7 @@ static int store_object(
                pack_size += sizeof(hdr) - pos;
        } else {
                e->depth = 0;
-               hdrlen = encode_header(type, datlen, hdr);
+               hdrlen = encode_header(type, dat->len, hdr);
                write_or_die(pack_data->pack_fd, hdr, hdrlen);
                pack_size += hdrlen;
        }
@@ -1132,24 +1114,60 @@ static int store_object(
        free(out);
        free(delta);
        if (last) {
-               if (!last->no_free)
-                       free(last->data);
-               last->data = dat;
+               if (last->no_swap) {
+                       last->data = *dat;
+               } else {
+                       strbuf_swap(&last->data, dat);
+               }
                last->offset = e->offset;
                last->depth = e->depth;
-               last->len = datlen;
        }
        return 0;
 }
 
+/* All calls must be guarded by find_object() or find_mark() to
+ * ensure the 'struct object_entry' passed was written by this
+ * process instance.  We unpack the entry by the offset, avoiding
+ * the need for the corresponding .idx file.  This unpacking rule
+ * works because we only use OBJ_REF_DELTA within the packfiles
+ * created by fast-import.
+ *
+ * oe must not be NULL.  Such an oe usually comes from giving
+ * an unknown SHA-1 to find_object() or an undefined mark to
+ * find_mark().  Callers must test for this condition and use
+ * the standard read_sha1_file() when it happens.
+ *
+ * oe->pack_id must not be MAX_PACK_ID.  Such an oe is usually from
+ * find_mark(), where the mark was reloaded from an existing marks
+ * file and is referencing an object that this fast-import process
+ * instance did not write out to a packfile.  Callers must test for
+ * this condition and use read_sha1_file() instead.
+ */
 static void *gfi_unpack_entry(
        struct object_entry *oe,
        unsigned long *sizep)
 {
        enum object_type type;
        struct packed_git *p = all_packs[oe->pack_id];
-       if (p == pack_data)
+       if (p == pack_data && p->pack_size < (pack_size + 20)) {
+               /* The object is stored in the packfile we are writing to
+                * and we have modified it since the last time we scanned
+                * back to read a previously written object.  If an old
+                * window covered [p->pack_size, p->pack_size + 20) its
+                * data is stale and is not valid.  Closing all windows
+                * and updating the packfile length ensures we can read
+                * the newly written data.
+                */
+               close_pack_windows(p);
+
+               /* We have to offer 20 bytes additional on the end of
+                * the packfile as the core unpacker code assumes the
+                * footer is present at the file end and must promise
+                * at least 20 bytes within any window it maps.  But
+                * we don't actually create the footer here.
+                */
                p->pack_size = pack_size + 20;
+       }
        return unpack_entry(p, oe->offset, &type, sizep);
 }
 
@@ -1233,14 +1251,10 @@ static int tecmp1 (const void *_a, const void *_b)
                b->name->str_dat, b->name->str_len, b->versions[1].mode);
 }
 
-static void mktree(struct tree_content *t,
-       int v,
-       unsigned long *szp,
-       struct dbuf *b)
+static void mktree(struct tree_content *t, int v, struct strbuf *b)
 {
        size_t maxlen = 0;
        unsigned int i;
-       char *c;
 
        if (!v)
                qsort(t->entries,t->entry_count,sizeof(t->entries[0]),tecmp0);
@@ -1252,28 +1266,23 @@ static void mktree(struct tree_content *t,
                        maxlen += t->entries[i]->name->str_len + 34;
        }
 
-       size_dbuf(b, maxlen);
-       c = b->buffer;
+       strbuf_reset(b);
+       strbuf_grow(b, maxlen);
        for (i = 0; i < t->entry_count; i++) {
                struct tree_entry *e = t->entries[i];
                if (!e->versions[v].mode)
                        continue;
-               c += sprintf(c, "%o", (unsigned int)e->versions[v].mode);
-               *c++ = ' ';
-               strcpy(c, e->name->str_dat);
-               c += e->name->str_len + 1;
-               hashcpy((unsigned char*)c, e->versions[v].sha1);
-               c += 20;
+               strbuf_addf(b, "%o %s%c", (unsigned int)e->versions[v].mode,
+                                       e->name->str_dat, '\0');
+               strbuf_add(b, e->versions[v].sha1, 20);
        }
-       *szp = c - (char*)b->buffer;
 }
 
 static void store_tree(struct tree_entry *root)
 {
        struct tree_content *t = root->tree;
        unsigned int i, j, del;
-       unsigned long new_len;
-       struct last_object lo;
+       struct last_object lo = { STRBUF_INIT, 0, 0, /* no_swap */ 1 };
        struct object_entry *le;
 
        if (!is_null_sha1(root->versions[1].sha1))
@@ -1285,23 +1294,15 @@ static void store_tree(struct tree_entry *root)
        }
 
        le = find_object(root->versions[0].sha1);
-       if (!S_ISDIR(root->versions[0].mode)
-               || !le
-               || le->pack_id != pack_id) {
-               lo.data = NULL;
-               lo.depth = 0;
-               lo.no_free = 0;
-       } else {
-               mktree(t, 0, &lo.len, &old_tree);
-               lo.data = old_tree.buffer;
+       if (S_ISDIR(root->versions[0].mode) && le && le->pack_id == pack_id) {
+               mktree(t, 0, &old_tree);
+               lo.data = old_tree;
                lo.offset = le->offset;
                lo.depth = t->delta_depth;
-               lo.no_free = 1;
        }
 
-       mktree(t, 1, &new_len, &new_tree);
-       store_object(OBJ_TREE, new_tree.buffer, new_len,
-               &lo, root->versions[1].sha1, 0);
+       mktree(t, 1, &new_tree);
+       store_object(OBJ_TREE, &new_tree, &lo, root->versions[1].sha1, 0);
 
        t->delta_depth = lo.depth;
        for (i = 0, j = 0, del = 0; i < t->entry_count; i++) {
@@ -1575,33 +1576,57 @@ static void dump_marks(void)
 
        f = fdopen(mark_fd, "w");
        if (!f) {
+               int saved_errno = errno;
                rollback_lock_file(&mark_lock);
                failure |= error("Unable to write marks file %s: %s",
-                       mark_file, strerror(errno));
+                       mark_file, strerror(saved_errno));
                return;
        }
 
+       /*
+        * Since the lock file was fdopen()'ed, it should not be close()'ed.
+        * Assign -1 to the lock file descriptor so that commit_lock_file()
+        * won't try to close() it.
+        */
+       mark_lock.fd = -1;
+
        dump_marks_helper(f, 0, marks);
-       fclose(f);
-       if (commit_lock_file(&mark_lock))
+       if (ferror(f) || fclose(f)) {
+               int saved_errno = errno;
+               rollback_lock_file(&mark_lock);
                failure |= error("Unable to write marks file %s: %s",
-                       mark_file, strerror(errno));
+                       mark_file, strerror(saved_errno));
+               return;
+       }
+
+       if (commit_lock_file(&mark_lock)) {
+               int saved_errno = errno;
+               rollback_lock_file(&mark_lock);
+               failure |= error("Unable to commit marks file %s: %s",
+                       mark_file, strerror(saved_errno));
+               return;
+       }
 }
 
-static void read_next_command(void)
+static int read_next_command(void)
 {
+       static int stdin_eof = 0;
+
+       if (stdin_eof) {
+               unread_command_buf = 0;
+               return EOF;
+       }
+
        do {
                if (unread_command_buf) {
                        unread_command_buf = 0;
-                       if (command_buf.eof)
-                               return;
                } else {
                        struct recent_command *rc;
 
-                       command_buf.buf = NULL;
-                       read_line(&command_buf, stdin, '\n');
-                       if (command_buf.eof)
-                               return;
+                       strbuf_detach(&command_buf, NULL);
+                       stdin_eof = strbuf_getline(&command_buf, stdin, '\n');
+                       if (stdin_eof)
+                               return EOF;
 
                        rc = rc_free;
                        if (rc)
@@ -1620,6 +1645,8 @@ static void read_next_command(void)
                        cmd_tail = rc;
                }
        } while (command_buf.buf[0] == '#');
+
+       return 0;
 }
 
 static void skip_optional_lf(void)
@@ -1639,42 +1666,36 @@ static void cmd_mark(void)
                next_mark = 0;
 }
 
-static void *cmd_data (size_t *size)
+static void cmd_data(struct strbuf *sb)
 {
-       size_t length;
-       char *buffer;
+       strbuf_reset(sb);
 
        if (prefixcmp(command_buf.buf, "data "))
                die("Expected 'data n' command, found: %s", command_buf.buf);
 
        if (!prefixcmp(command_buf.buf + 5, "<<")) {
                char *term = xstrdup(command_buf.buf + 5 + 2);
-               size_t sz = 8192, term_len = command_buf.len - 5 - 2;
-               length = 0;
-               buffer = xmalloc(sz);
-               command_buf.buf = NULL;
+               size_t term_len = command_buf.len - 5 - 2;
+
+               strbuf_detach(&command_buf, NULL);
                for (;;) {
-                       read_line(&command_buf, stdin, '\n');
-                       if (command_buf.eof)
+                       if (strbuf_getline(&command_buf, stdin, '\n') == EOF)
                                die("EOF in data (terminator '%s' not found)", term);
                        if (term_len == command_buf.len
                                && !strcmp(term, command_buf.buf))
                                break;
-                       ALLOC_GROW(buffer, length + command_buf.len, sz);
-                       memcpy(buffer + length,
-                               command_buf.buf,
-                               command_buf.len - 1);
-                       length += command_buf.len - 1;
-                       buffer[length++] = '\n';
+                       strbuf_addbuf(sb, &command_buf);
+                       strbuf_addch(sb, '\n');
                }
                free(term);
        }
        else {
-               size_t n = 0;
+               size_t n = 0, length;
+
                length = strtoul(command_buf.buf + 5, NULL, 10);
-               buffer = xmalloc(length);
+
                while (n < length) {
-                       size_t s = fread(buffer + n, 1, length - n, stdin);
+                       size_t s = strbuf_fread(sb, length - n, stdin);
                        if (!s && feof(stdin))
                                die("EOF in data (%lu bytes remaining)",
                                        (unsigned long)(length - n));
@@ -1683,8 +1704,6 @@ static void *cmd_data (size_t *size)
        }
 
        skip_optional_lf();
-       *size = length;
-       return buffer;
 }
 
 static int validate_raw_date(const char *src, char *result, int maxlen)
@@ -1747,15 +1766,12 @@ static char *parse_ident(const char *buf)
 
 static void cmd_new_blob(void)
 {
-       size_t l;
-       void *d;
+       static struct strbuf buf = STRBUF_INIT;
 
        read_next_command();
        cmd_mark();
-       d = cmd_data(&l);
-
-       if (store_object(OBJ_BLOB, d, l, &last_blob, NULL, next_mark))
-               free(d);
+       cmd_data(&buf);
+       store_object(OBJ_BLOB, &buf, &last_blob, NULL, next_mark);
 }
 
 static void unload_one_branch(void)
@@ -1805,7 +1821,7 @@ static void load_branch(struct branch *b)
 static void file_change_m(struct branch *b)
 {
        const char *p = command_buf.buf + 2;
-       char *p_uq;
+       static struct strbuf uq = STRBUF_INIT;
        const char *endp;
        struct object_entry *oe = oe;
        unsigned char sha1[20];
@@ -1843,22 +1859,23 @@ static void file_change_m(struct branch *b)
        if (*p++ != ' ')
                die("Missing space after SHA1: %s", command_buf.buf);
 
-       p_uq = unquote_c_style(p, &endp);
-       if (p_uq) {
+       strbuf_reset(&uq);
+       if (!unquote_c_style(&uq, p, &endp)) {
                if (*endp)
                        die("Garbage after path in: %s", command_buf.buf);
-               p = p_uq;
+               p = uq.buf;
        }
 
        if (inline_data) {
-               size_t l;
-               void *d;
-               if (!p_uq)
-                       p = p_uq = xstrdup(p);
+               static struct strbuf buf = STRBUF_INIT;
+
+               if (p != uq.buf) {
+                       strbuf_addstr(&uq, p);
+                       p = uq.buf;
+               }
                read_next_command();
-               d = cmd_data(&l);
-               if (store_object(OBJ_BLOB, d, l, &last_blob, sha1, 0))
-                       free(d);
+               cmd_data(&buf);
+               store_object(OBJ_BLOB, &buf, &last_blob, sha1, 0);
        } else if (oe) {
                if (oe->type != OBJ_BLOB)
                        die("Not a blob (actually a %s): %s",
@@ -1873,58 +1890,54 @@ static void file_change_m(struct branch *b)
        }
 
        tree_content_set(&b->branch_tree, p, sha1, S_IFREG | mode, NULL);
-       free(p_uq);
 }
 
 static void file_change_d(struct branch *b)
 {
        const char *p = command_buf.buf + 2;
-       char *p_uq;
+       static struct strbuf uq = STRBUF_INIT;
        const char *endp;
 
-       p_uq = unquote_c_style(p, &endp);
-       if (p_uq) {
+       strbuf_reset(&uq);
+       if (!unquote_c_style(&uq, p, &endp)) {
                if (*endp)
                        die("Garbage after path in: %s", command_buf.buf);
-               p = p_uq;
+               p = uq.buf;
        }
        tree_content_remove(&b->branch_tree, p, NULL);
-       free(p_uq);
 }
 
 static void file_change_cr(struct branch *b, int rename)
 {
        const char *s, *d;
-       char *s_uq, *d_uq;
+       static struct strbuf s_uq = STRBUF_INIT;
+       static struct strbuf d_uq = STRBUF_INIT;
        const char *endp;
        struct tree_entry leaf;
 
        s = command_buf.buf + 2;
-       s_uq = unquote_c_style(s, &endp);
-       if (s_uq) {
+       strbuf_reset(&s_uq);
+       if (!unquote_c_style(&s_uq, s, &endp)) {
                if (*endp != ' ')
                        die("Missing space after source: %s", command_buf.buf);
-       }
-       else {
+       } else {
                endp = strchr(s, ' ');
                if (!endp)
                        die("Missing space after source: %s", command_buf.buf);
-               s_uq = xmalloc(endp - s + 1);
-               memcpy(s_uq, s, endp - s);
-               s_uq[endp - s] = 0;
+               strbuf_add(&s_uq, s, endp - s);
        }
-       s = s_uq;
+       s = s_uq.buf;
 
        endp++;
        if (!*endp)
                die("Missing dest: %s", command_buf.buf);
 
        d = endp;
-       d_uq = unquote_c_style(d, &endp);
-       if (d_uq) {
+       strbuf_reset(&d_uq);
+       if (!unquote_c_style(&d_uq, d, &endp)) {
                if (*endp)
                        die("Garbage after dest in: %s", command_buf.buf);
-               d = d_uq;
+               d = d_uq.buf;
        }
 
        memset(&leaf, 0, sizeof(leaf));
@@ -1938,9 +1951,6 @@ static void file_change_cr(struct branch *b, int rename)
                leaf.versions[1].sha1,
                leaf.versions[1].mode,
                leaf.tree);
-
-       free(s_uq);
-       free(d_uq);
 }
 
 static void file_change_deleteall(struct branch *b)
@@ -2065,9 +2075,8 @@ static struct hash_list *cmd_merge(unsigned int *count)
 
 static void cmd_new_commit(void)
 {
+       static struct strbuf msg = STRBUF_INIT;
        struct branch *b;
-       void *msg;
-       size_t msglen;
        char *sp;
        char *author = NULL;
        char *committer = NULL;
@@ -2092,7 +2101,7 @@ static void cmd_new_commit(void)
        }
        if (!committer)
                die("Expected committer but didn't get one");
-       msg = cmd_data(&msglen);
+       cmd_data(&msg);
        read_next_command();
        cmd_from(b);
        merge_list = cmd_merge(&merge_count);
@@ -2104,7 +2113,7 @@ static void cmd_new_commit(void)
        }
 
        /* file_change* */
-       while (!command_buf.eof && command_buf.len > 1) {
+       while (command_buf.len > 0) {
                if (!prefixcmp(command_buf.buf, "M "))
                        file_change_m(b);
                else if (!prefixcmp(command_buf.buf, "D "))
@@ -2119,53 +2128,47 @@ static void cmd_new_commit(void)
                        unread_command_buf = 1;
                        break;
                }
-               read_next_command();
+               if (read_next_command() == EOF)
+                       break;
        }
 
        /* build the tree and the commit */
        store_tree(&b->branch_tree);
        hashcpy(b->branch_tree.versions[0].sha1,
                b->branch_tree.versions[1].sha1);
-       size_dbuf(&new_data, 114 + msglen
-               + merge_count * 49
-               + (author
-                       ? strlen(author) + strlen(committer)
-                       : 2 * strlen(committer)));
-       sp = new_data.buffer;
-       sp += sprintf(sp, "tree %s\n",
+
+       strbuf_reset(&new_data);
+       strbuf_addf(&new_data, "tree %s\n",
                sha1_to_hex(b->branch_tree.versions[1].sha1));
        if (!is_null_sha1(b->sha1))
-               sp += sprintf(sp, "parent %s\n", sha1_to_hex(b->sha1));
+               strbuf_addf(&new_data, "parent %s\n", sha1_to_hex(b->sha1));
        while (merge_list) {
                struct hash_list *next = merge_list->next;
-               sp += sprintf(sp, "parent %s\n", sha1_to_hex(merge_list->sha1));
+               strbuf_addf(&new_data, "parent %s\n", sha1_to_hex(merge_list->sha1));
                free(merge_list);
                merge_list = next;
        }
-       sp += sprintf(sp, "author %s\n", author ? author : committer);
-       sp += sprintf(sp, "committer %s\n", committer);
-       *sp++ = '\n';
-       memcpy(sp, msg, msglen);
-       sp += msglen;
+       strbuf_addf(&new_data,
+               "author %s\n"
+               "committer %s\n"
+               "\n",
+               author ? author : committer, committer);
+       strbuf_addbuf(&new_data, &msg);
        free(author);
        free(committer);
-       free(msg);
 
-       if (!store_object(OBJ_COMMIT,
-               new_data.buffer, sp - (char*)new_data.buffer,
-               NULL, b->sha1, next_mark))
+       if (!store_object(OBJ_COMMIT, &new_data, NULL, b->sha1, next_mark))
                b->pack_id = pack_id;
        b->last_commit = object_count_by_type[OBJ_COMMIT];
 }
 
 static void cmd_new_tag(void)
 {
+       static struct strbuf msg = STRBUF_INIT;
        char *sp;
        const char *from;
        char *tagger;
        struct branch *s;
-       void *msg;
-       size_t msglen;
        struct tag *t;
        uintmax_t from_mark = 0;
        unsigned char sha1[20];
@@ -2216,24 +2219,21 @@ static void cmd_new_tag(void)
 
        /* tag payload/message */
        read_next_command();
-       msg = cmd_data(&msglen);
+       cmd_data(&msg);
 
        /* build the tag object */
-       size_dbuf(&new_data, 67+strlen(t->name)+strlen(tagger)+msglen);
-       sp = new_data.buffer;
-       sp += sprintf(sp, "object %s\n", sha1_to_hex(sha1));
-       sp += sprintf(sp, "type %s\n", commit_type);
-       sp += sprintf(sp, "tag %s\n", t->name);
-       sp += sprintf(sp, "tagger %s\n", tagger);
-       *sp++ = '\n';
-       memcpy(sp, msg, msglen);
-       sp += msglen;
+       strbuf_reset(&new_data);
+       strbuf_addf(&new_data,
+               "object %s\n"
+               "type %s\n"
+               "tag %s\n"
+               "tagger %s\n"
+               "\n",
+               sha1_to_hex(sha1), commit_type, t->name, tagger);
+       strbuf_addbuf(&new_data, &msg);
        free(tagger);
-       free(msg);
 
-       if (store_object(OBJ_TAG, new_data.buffer,
-               sp - (char*)new_data.buffer,
-               NULL, t->sha1, 0))
+       if (store_object(OBJ_TAG, &new_data, NULL, t->sha1, 0))
                t->pack_id = MAX_PACK_ID;
        else
                t->pack_id = pack_id;
@@ -2259,7 +2259,7 @@ static void cmd_reset_branch(void)
        else
                b = new_branch(sp);
        read_next_command();
-       if (!cmd_from(b) && command_buf.len > 1)
+       if (!cmd_from(b) && command_buf.len > 0)
                unread_command_buf = 1;
 }
 
@@ -2276,7 +2276,7 @@ static void cmd_checkpoint(void)
 
 static void cmd_progress(void)
 {
-       fwrite(command_buf.buf, 1, command_buf.len - 1, stdout);
+       fwrite(command_buf.buf, 1, command_buf.len, stdout);
        fputc('\n', stdout);
        fflush(stdout);
        skip_optional_lf();
@@ -2317,6 +2317,27 @@ static void import_marks(const char *input_file)
        fclose(f);
 }
 
+static int git_pack_config(const char *k, const char *v)
+{
+       if (!strcmp(k, "pack.depth")) {
+               max_depth = git_config_int(k, v);
+               if (max_depth > MAX_DEPTH)
+                       max_depth = MAX_DEPTH;
+               return 0;
+       }
+       if (!strcmp(k, "pack.compression")) {
+               int level = git_config_int(k, v);
+               if (level == -1)
+                       level = Z_DEFAULT_COMPRESSION;
+               else if (level < 0 || level > Z_BEST_COMPRESSION)
+                       die("bad pack compression level %d", level);
+               pack_compression_level = level;
+               pack_compression_seen = 1;
+               return 0;
+       }
+       return git_default_config(k, v);
+}
+
 static const char fast_import_usage[] =
 "git-fast-import [--date-format=f] [--max-pack-size=n] [--depth=n] [--active-branches=n] [--export-marks=marks.file]";
 
@@ -2324,9 +2345,12 @@ int main(int argc, const char **argv)
 {
        unsigned int i, show_stats = 1;
 
-       git_config(git_default_config);
+       git_config(git_pack_config);
+       if (!pack_compression_seen && core_compression_seen)
+               pack_compression_level = core_compression_level;
+
        alloc_objects(object_entry_alloc);
-       strbuf_init(&command_buf);
+       strbuf_init(&command_buf, 0);
        atom_table = xcalloc(atom_table_sz, sizeof(struct atom_str*));
        branch_table = xcalloc(branch_table_sz, sizeof(struct branch*));
        avail_tree_table = xcalloc(avail_tree_table_sz, sizeof(struct avail_tree_content*));
@@ -2387,11 +2411,8 @@ int main(int argc, const char **argv)
        prepare_packed_git();
        start_packfile();
        set_die_routine(die_nicely);
-       for (;;) {
-               read_next_command();
-               if (command_buf.eof)
-                       break;
-               else if (!strcmp("blob", command_buf.buf))
+       while (read_next_command() != EOF) {
+               if (!strcmp("blob", command_buf.buf))
                        cmd_new_blob();
                else if (!prefixcmp(command_buf.buf, "commit "))
                        cmd_new_commit();