Make "diff-tree" take commit objects too, like "diff-cache" does.
[git] / diff-tree.c
1 #include "cache.h"
2
3 static int recursive = 0;
4 static int line_termination = '\n';
5
6 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
7
8 static void update_tree_entry(void **bufp, unsigned long *sizep)
9 {
10         void *buf = *bufp;
11         unsigned long size = *sizep;
12         int len = strlen(buf) + 1 + 20;
13
14         if (size < len)
15                 die("corrupt tree file");
16         *bufp = buf + len;
17         *sizep = size - len;
18 }
19
20 static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
21 {
22         int len = strlen(tree)+1;
23         const unsigned char *sha1 = tree + len;
24         const char *path = strchr(tree, ' ');
25
26         if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
27                 die("corrupt tree file");
28         *pathp = path+1;
29         return sha1;
30 }
31
32 static char *malloc_base(const char *base, const char *path, int pathlen)
33 {
34         int baselen = strlen(base);
35         char *newbase = malloc(baselen + pathlen + 2);
36         memcpy(newbase, base, baselen);
37         memcpy(newbase + baselen, path, pathlen);
38         memcpy(newbase + baselen + pathlen, "/", 2);
39         return newbase;
40 }
41
42 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
43
44 /* A whole sub-tree went away or appeared */
45 static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
46 {
47         while (size) {
48                 show_file(prefix, tree, size, base);
49                 update_tree_entry(&tree, &size);
50         }
51 }
52
53 /* A file entry went away or appeared */
54 static void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
55 {
56         unsigned mode;
57         const char *path;
58         const unsigned char *sha1 = extract(tree, size, &path, &mode);
59
60         if (recursive && S_ISDIR(mode)) {
61                 char type[20];
62                 unsigned long size;
63                 char *newbase = malloc_base(base, path, strlen(path));
64                 void *tree;
65
66                 tree = read_sha1_file(sha1, type, &size);
67                 if (!tree || strcmp(type, "tree"))
68                         die("corrupt tree sha %s", sha1_to_hex(sha1));
69
70                 show_tree(prefix, tree, size, newbase);
71                 
72                 free(tree);
73                 free(newbase);
74                 return;
75         }
76
77         printf("%s%o\t%s\t%s\t%s%s%c", prefix, mode,
78                S_ISDIR(mode) ? "tree" : "blob",
79                sha1_to_hex(sha1), base, path,
80                line_termination);
81 }
82
83 static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
84 {
85         unsigned mode1, mode2;
86         const char *path1, *path2;
87         const unsigned char *sha1, *sha2;
88         int cmp, pathlen1, pathlen2;
89         char old_sha1_hex[50];
90
91         sha1 = extract(tree1, size1, &path1, &mode1);
92         sha2 = extract(tree2, size2, &path2, &mode2);
93
94         pathlen1 = strlen(path1);
95         pathlen2 = strlen(path2);
96         cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
97         if (cmp < 0) {
98                 show_file("-", tree1, size1, base);
99                 return -1;
100         }
101         if (cmp > 0) {
102                 show_file("+", tree2, size2, base);
103                 return 1;
104         }
105         if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
106                 return 0;
107
108         /*
109          * If the filemode has changed to/from a directory from/to a regular
110          * file, we need to consider it a remove and an add.
111          */
112         if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
113                 show_file("-", tree1, size1, base);
114                 show_file("+", tree2, size2, base);
115                 return 0;
116         }
117
118         if (recursive && S_ISDIR(mode1)) {
119                 int retval;
120                 char *newbase = malloc_base(base, path1, pathlen1);
121                 retval = diff_tree_sha1(sha1, sha2, newbase);
122                 free(newbase);
123                 return retval;
124         }
125
126         strcpy(old_sha1_hex, sha1_to_hex(sha1));
127         printf("*%o->%o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
128                S_ISDIR(mode1) ? "tree" : "blob",
129                old_sha1_hex, sha1_to_hex(sha2), base, path1,
130                line_termination);
131         return 0;
132 }
133
134 static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
135 {
136         while (size1 | size2) {
137                 if (!size1) {
138                         show_file("+", tree2, size2, base);
139                         update_tree_entry(&tree2, &size2);
140                         continue;
141                 }
142                 if (!size2) {
143                         show_file("-", tree1, size1, base);
144                         update_tree_entry(&tree1, &size1);
145                         continue;
146                 }
147                 switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
148                 case -1:
149                         update_tree_entry(&tree1, &size1);
150                         continue;
151                 case 0:
152                         update_tree_entry(&tree1, &size1);
153                         /* Fallthrough */
154                 case 1:
155                         update_tree_entry(&tree2, &size2);
156                         continue;
157                 }
158                 die("diff-tree: internal error");
159         }
160         return 0;
161 }
162
163 static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
164 {
165         void *tree1, *tree2;
166         unsigned long size1, size2;
167         char type[20];
168         int retval;
169
170         tree1 = read_sha1_file(old, type, &size1);
171         if (!tree1 || strcmp(type, "tree"))
172                 die("unable to read source tree (%s)", sha1_to_hex(old));
173         tree2 = read_sha1_file(new, type, &size2);
174         if (!tree2 || strcmp(type, "tree"))
175                 die("unable to read destination tree (%s)", sha1_to_hex(new));
176         retval = diff_tree(tree1, size1, tree2, size2, base);
177         free(tree1);
178         free(tree2);
179         return retval;
180 }
181
182 static void commit_to_tree(unsigned char *sha1)
183 {
184         void *buf;
185         char type[20];
186         unsigned long size;
187
188         buf = read_sha1_file(sha1, type, &size);
189         if (buf) {
190                 if (!strcmp(type, "commit"))
191                         get_sha1_hex(buf+5, sha1);
192                 free(buf);
193         }
194 }
195
196 int main(int argc, char **argv)
197 {
198         unsigned char old[20], new[20];
199
200         while (argc > 3) {
201                 char *arg = argv[1];
202                 argv++;
203                 argc--;
204                 if (!strcmp(arg, "-r")) {
205                         recursive = 1;
206                         continue;
207                 }
208                 if (!strcmp(arg, "-z")) {
209                         line_termination = '\0';
210                         continue;
211                 }
212                 usage("diff-tree [-r] [-z] <tree sha1> <tree sha1>");
213         }
214
215         if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
216                 usage("diff-tree <tree sha1> <tree sha1>");
217         commit_to_tree(old);
218         commit_to_tree(new);
219         return diff_tree_sha1(old, new, "");
220 }