tree-diff: consolidate code for emitting diffs and recursion in one place
[gitweb.git] / tree-diff.c
index 11c3550177dbaab30596be2fc3c1633f2a0485f8..1af82190339b058549cb2197b92edb1369c0ba42 100644 (file)
@@ -6,8 +6,8 @@
 #include "diffcore.h"
 #include "tree.h"
 
-static void show_entry(struct diff_options *opt, const char *prefix,
-                      struct tree_desc *desc, struct strbuf *base);
+static void show_path(struct strbuf *base, struct diff_options *opt,
+                     struct tree_desc *t1, struct tree_desc *t2);
 
 static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
                              struct strbuf *base, struct diff_options *opt)
@@ -16,111 +16,130 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
        const char *path1, *path2;
        const unsigned char *sha1, *sha2;
        int cmp, pathlen1, pathlen2;
-       int old_baselen = base->len;
 
        sha1 = tree_entry_extract(t1, &path1, &mode1);
        sha2 = tree_entry_extract(t2, &path2, &mode2);
 
        pathlen1 = tree_entry_len(&t1->entry);
        pathlen2 = tree_entry_len(&t2->entry);
+
+       /*
+        * NOTE files and directories *always* compare differently,
+        * even when having the same name.
+        */
        cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
        if (cmp < 0) {
-               show_entry(opt, "-", t1, base);
+               show_path(base, opt, t1, /*t2=*/NULL);
                return -1;
        }
        if (cmp > 0) {
-               show_entry(opt, "+", t2, base);
+               show_path(base, opt, /*t1=*/NULL, t2);
                return 1;
        }
        if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
                return 0;
 
-       /*
-        * If the filemode has changed to/from a directory from/to a regular
-        * file, we need to consider it a remove and an add.
-        */
-       if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
-               show_entry(opt, "-", t1, base);
-               show_entry(opt, "+", t2, base);
-               return 0;
-       }
-
-       strbuf_add(base, path1, pathlen1);
-       if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
-               if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
-                       opt->change(opt, mode1, mode2,
-                                   sha1, sha2, 1, 1, base->buf, 0, 0);
-               }
-               strbuf_addch(base, '/');
-               diff_tree_sha1(sha1, sha2, base->buf, opt);
-       } else {
-               opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0);
-       }
-       strbuf_setlen(base, old_baselen);
+       show_path(base, opt, t1, t2);
        return 0;
 }
 
-/* A whole sub-tree went away or appeared */
-static void show_tree(struct diff_options *opt, const char *prefix,
-                     struct tree_desc *desc, struct strbuf *base)
+
+/* convert path, t1/t2 -> opt->diff_*() callbacks */
+static void emit_diff(struct diff_options *opt, struct strbuf *path,
+                     struct tree_desc *t1, struct tree_desc *t2)
 {
-       enum interesting match = entry_not_interesting;
-       for (; desc->size; update_tree_entry(desc)) {
-               if (match != all_entries_interesting) {
-                       match = tree_entry_interesting(&desc->entry, base, 0,
-                                                      &opt->pathspec);
-                       if (match == all_entries_not_interesting)
-                               break;
-                       if (match == entry_not_interesting)
-                               continue;
+       unsigned int mode1 = t1 ? t1->entry.mode : 0;
+       unsigned int mode2 = t2 ? t2->entry.mode : 0;
+
+       if (mode1 && mode2) {
+               opt->change(opt, mode1, mode2, t1->entry.sha1, t2->entry.sha1,
+                       1, 1, path->buf, 0, 0);
+       }
+       else {
+               const unsigned char *sha1;
+               unsigned int mode;
+               int addremove;
+
+               if (mode2) {
+                       addremove = '+';
+                       sha1 = t2->entry.sha1;
+                       mode = mode2;
+               } else {
+                       addremove = '-';
+                       sha1 = t1->entry.sha1;
+                       mode = mode1;
                }
-               show_entry(opt, prefix, desc, base);
+
+               opt->add_remove(opt, addremove, mode, sha1, 1, path->buf, 0);
        }
 }
 
-/* A file entry went away or appeared */
-static void show_entry(struct diff_options *opt, const char *prefix,
-                      struct tree_desc *desc, struct strbuf *base)
+
+/* new path should be added to diff
+ *
+ * 3 cases on how/when it should be called and behaves:
+ *
+ *     !t1,  t2        -> path added, parent lacks it
+ *      t1, !t2        -> path removed from parent
+ *      t1,  t2        -> path modified
+ */
+static void show_path(struct strbuf *base, struct diff_options *opt,
+                     struct tree_desc *t1, struct tree_desc *t2)
 {
        unsigned mode;
        const char *path;
-       const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
-       int pathlen = tree_entry_len(&desc->entry);
+       int pathlen;
        int old_baselen = base->len;
+       int isdir, recurse = 0, emitthis = 1;
 
-       strbuf_add(base, path, pathlen);
-       if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
-               enum object_type type;
-               struct tree_desc inner;
-               void *tree;
-               unsigned long size;
+       /* at least something has to be valid */
+       assert(t1 || t2);
+
+       if (t2) {
+               /* path present in resulting tree */
+               tree_entry_extract(t2, &path, &mode);
+               pathlen = tree_entry_len(&t2->entry);
+               isdir = S_ISDIR(mode);
+       } else {
+               /*
+                * a path was removed - take path from parent. Also take
+                * mode from parent, to decide on recursion.
+                */
+               tree_entry_extract(t1, &path, &mode);
+               pathlen = tree_entry_len(&t1->entry);
 
-               tree = read_sha1_file(sha1, &type, &size);
-               if (!tree || type != OBJ_TREE)
-                       die("corrupt tree sha %s", sha1_to_hex(sha1));
+               isdir = S_ISDIR(mode);
+               mode = 0;
+       }
 
-               if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
-                       opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0);
+       if (DIFF_OPT_TST(opt, RECURSIVE) && isdir) {
+               recurse = 1;
+               emitthis = DIFF_OPT_TST(opt, TREE_IN_RECURSIVE);
+       }
 
-               strbuf_addch(base, '/');
+       strbuf_add(base, path, pathlen);
 
-               init_tree_desc(&inner, tree, size);
-               show_tree(opt, prefix, &inner, base);
-               free(tree);
-       } else
-               opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0);
+       if (emitthis)
+               emit_diff(opt, base, t1, t2);
+
+       if (recurse) {
+               strbuf_addch(base, '/');
+               diff_tree_sha1(t1 ? t1->entry.sha1 : NULL,
+                              t2 ? t2->entry.sha1 : NULL, base->buf, opt);
+       }
 
        strbuf_setlen(base, old_baselen);
 }
 
 static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
-                              struct diff_options *opt,
-                              enum interesting *match)
+                              struct diff_options *opt)
 {
+       enum interesting match;
+
        while (t->size) {
-               *match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
-               if (*match) {
-                       if (*match == all_entries_not_interesting)
+               match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
+               if (match) {
+                       if (match == all_entries_not_interesting)
                                t->size = 0;
                        break;
                }
@@ -133,8 +152,6 @@ int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
 {
        struct strbuf base;
        int baselen = strlen(base_str);
-       enum interesting t1_match = entry_not_interesting;
-       enum interesting t2_match = entry_not_interesting;
 
        /* Enable recursion indefinitely */
        opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
@@ -146,18 +163,18 @@ int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
                if (diff_can_quit_early(opt))
                        break;
                if (opt->pathspec.nr) {
-                       skip_uninteresting(t1, &base, opt, &t1_match);
-                       skip_uninteresting(t2, &base, opt, &t2_match);
+                       skip_uninteresting(t1, &base, opt);
+                       skip_uninteresting(t2, &base, opt);
                }
                if (!t1->size) {
                        if (!t2->size)
                                break;
-                       show_entry(opt, "+", t2, &base);
+                       show_path(&base, opt, /*t1=*/NULL, t2);
                        update_tree_entry(t2);
                        continue;
                }
                if (!t2->size) {
-                       show_entry(opt, "-", t1, &base);
+                       show_path(&base, opt, t1, /*t2=*/NULL);
                        update_tree_entry(t1);
                        continue;
                }