Make "rev-tree" more efficient and more useful.

Slight change of output format: it now lists all parents on the same line.

This allows it to work on initial commits too (which have no parents), and
also makes the output format a lot more intuitive.

diff --git a/rev-tree.c b/rev-tree.c
index bbf6281..73c9d1f 100644 (file)
--- a/rev-tree.c
+++ b/rev-tree.c
@@ -1,28 +1,33 @@
 #include "cache.h"
 
-struct relationship {
+#define SEEN 1
+
+struct parent {
+       struct revision *parent;
+       struct parent *next;
+};
+
+struct revision {
+       unsigned int flags;
        unsigned char sha1[20];
-       unsigned char parent[20];
+       struct parent *parent;
 };
 
-static struct relationship **rels;
-static int nr_rels, rel_allocs;
+static struct revision **revs;
+static int nr_revs, rev_allocs;
 
-static int find_relationship(unsigned char *sha1, unsigned char *parent)
+static int find_rev(unsigned char *sha1)
 {
-       int first = 0, last = nr_rels;
+       int first = 0, last = nr_revs;
 
        while (first < last) {
                int next = (first + last) / 2;
-               struct relationship *rel = rels[next];
+               struct revision *rev = revs[next];
                int cmp;
 
-               cmp = memcmp(sha1, rel->sha1, 20);
-               if (!cmp) {
-                       cmp = memcmp(parent, rel->parent, 20);
-                       if (!cmp)
-                               return next;
-               }
+               cmp = memcmp(sha1, rev->sha1, 20);
+               if (!cmp)
+                       return next;
                if (cmp < 0) {
                        last = next;
                        continue;
@@ -32,56 +37,69 @@ static int find_relationship(unsigned char *sha1, unsigned char *parent)
        return -first-1;
 }
 
-static int add_relationship(unsigned char *sha1, unsigned char *parent)
+static struct revision *lookup_rev(unsigned char *sha1)
 {
-       struct relationship *n;
-       int pos;
+       int pos = find_rev(sha1);
+       struct revision *n;
 
-       pos = find_relationship(sha1, parent);
        if (pos >= 0)
-               return 0;
+               return revs[pos];
+       
        pos = -pos-1;
 
-       if (rel_allocs == nr_rels) {
-               rel_allocs = alloc_nr(rel_allocs);
-               rels = realloc(rels, rel_allocs * sizeof(struct relationship *));
+       if (rev_allocs == nr_revs) {
+               rev_allocs = alloc_nr(rev_allocs);
+               revs = realloc(revs, rev_allocs * sizeof(struct revision *));
        }
-       n = malloc(sizeof(struct relationship));
-       
-       memmove(rels + pos + 1, rels + pos, (nr_rels - pos) * sizeof(struct relationship *));
-       rels[pos] = n;
-       nr_rels++;
+       n = malloc(sizeof(struct revision));
+
+       n->flags = 0;
        memcpy(n->sha1, sha1, 20);
-       memcpy(n->parent, parent, 20);
-       return 1;
+       n->parent = NULL;
+
+       /* Insert it into the right place */
+       memmove(revs + pos + 1, revs + pos, (nr_revs - pos) * sizeof(struct revision *));
+       revs[pos] = n;
+       nr_revs++;
+
+       return n;
 }
 
-static int already_seen(unsigned char *sha1)
+static int add_relationship(struct revision *rev, unsigned char *parent_sha)
 {
-       static char null_sha[20];
-       int pos = find_relationship(sha1, null_sha);
+       struct revision *parent_rev = lookup_rev(parent_sha);
+       struct parent **pp = &rev->parent, *p;
 
-       if (pos < 0) 
-               pos = -pos-1;
-       if (pos < nr_rels && !memcmp(sha1, rels[pos]->sha1, 20))
-               return 1;
-       return 0;
+       while ((p = *pp) != NULL) {
+               if (p->parent == parent_rev)
+                       return 0;
+               pp = &p->next;
+       }
+
+       p = malloc(sizeof(*p));
+       p->parent = parent_rev;
+       p->next = NULL;
+       *pp = p;
+       return 1;
 }
 
 static int parse_commit(unsigned char *sha1)
 {
-       if (!already_seen(sha1)) {
+       struct revision *rev = lookup_rev(sha1);
+
+       if (!(rev->flags & SEEN)) {
                void *buffer;
                unsigned long size;
                char type[20];
                unsigned char parent[20];
 
+               rev->flags |= SEEN;
                buffer = read_sha1_file(sha1, type, &size);
                if (!buffer || strcmp(type, "commit"))
                        return -1;
                buffer += 46; /* "tree " + "hex sha1" + "\n" */
                while (!memcmp(buffer, "parent ", 7) && !get_sha1_hex(buffer+7, parent)) {
-                       add_relationship(sha1, parent);
+                       add_relationship(rev, parent);
                        parse_commit(parent);
                        buffer += 48;   /* "parent " + "hex sha1" + "\n" */
                }
@@ -98,7 +116,7 @@ static void read_cache_file(const char *path)
                unsigned char sha1[20], parent[20];
                if (get_sha1_hex(line, sha1) || get_sha1_hex(line + 41, parent))
                        usage("bad rev-tree cache file %s", path);
-               add_relationship(sha1, parent);
+               add_relationship(lookup_rev(sha1), parent);
        }
        fclose(file);
 }
@@ -128,11 +146,17 @@ int main(int argc, char **argv)
        if (argc != 2 || get_sha1_hex(argv[1], sha1))
                usage("rev-tree [--cache <cache-file>] <commit-id>");
        parse_commit(sha1);
-       for (i = 0; i < nr_rels; i++) {
-               char parent[60];
-               struct relationship *rel = rels[i];
-               strcpy(parent, sha1_to_hex(rel->parent));
-               printf("%s %s\n", sha1_to_hex(rel->sha1), parent);
+       for (i = 0; i < nr_revs; i++) {
+               struct revision *rev = revs[i];
+               struct parent *p;
+
+               printf("%s", sha1_to_hex(rev->sha1));
+               p = rev->parent;
+               while (p) {
+                       printf(" %s", sha1_to_hex(p->parent->sha1));
+                       p = p->next;
+               }
+               printf("\n");
        }
        return 0;
 }