Rework object refs tracking to reduce memory usage
[git.git] / tree.c
1 #include "tree.h"
2 #include "blob.h"
3 #include "commit.h"
4 #include "tag.h"
5 #include "cache.h"
6 #include <stdlib.h>
7
8 const char *tree_type = "tree";
9
10 static int read_one_entry(unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
11 {
12         int len = strlen(pathname);
13         unsigned int size = cache_entry_size(baselen + len);
14         struct cache_entry *ce = xmalloc(size);
15
16         memset(ce, 0, size);
17
18         ce->ce_mode = create_ce_mode(mode);
19         ce->ce_flags = create_ce_flags(baselen + len, stage);
20         memcpy(ce->name, base, baselen);
21         memcpy(ce->name + baselen, pathname, len+1);
22         memcpy(ce->sha1, sha1, 20);
23         return add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
24 }
25
26 static int match_tree_entry(const char *base, int baselen, const char *path, unsigned int mode, const char **paths)
27 {
28         const char *match;
29         int pathlen;
30
31         if (!paths)
32                 return 1;
33         pathlen = strlen(path);
34         while ((match = *paths++) != NULL) {
35                 int matchlen = strlen(match);
36
37                 if (baselen >= matchlen) {
38                         /* If it doesn't match, move along... */
39                         if (strncmp(base, match, matchlen))
40                                 continue;
41                         /* The base is a subdirectory of a path which was specified. */
42                         return 1;
43                 }
44
45                 /* Does the base match? */
46                 if (strncmp(base, match, baselen))
47                         continue;
48
49                 match += baselen;
50                 matchlen -= baselen;
51
52                 if (pathlen > matchlen)
53                         continue;
54
55                 if (matchlen > pathlen) {
56                         if (match[pathlen] != '/')
57                                 continue;
58                         if (!S_ISDIR(mode))
59                                 continue;
60                 }
61
62                 if (strncmp(path, match, pathlen))
63                         continue;
64
65                 return 1;
66         }
67         return 0;
68 }
69
70 static int read_tree_recursive(void *buffer, unsigned long size,
71                                const char *base, int baselen,
72                                int stage, const char **match)
73 {
74         while (size) {
75                 int len = strlen(buffer)+1;
76                 unsigned char *sha1 = buffer + len;
77                 char *path = strchr(buffer, ' ')+1;
78                 unsigned int mode;
79
80                 if (size < len + 20 || sscanf(buffer, "%o", &mode) != 1)
81                         return -1;
82
83                 buffer = sha1 + 20;
84                 size -= len + 20;
85
86                 if (!match_tree_entry(base, baselen, path, mode, match))
87                         continue;
88
89                 if (S_ISDIR(mode)) {
90                         int retval;
91                         int pathlen = strlen(path);
92                         char *newbase;
93                         void *eltbuf;
94                         char elttype[20];
95                         unsigned long eltsize;
96
97                         eltbuf = read_sha1_file(sha1, elttype, &eltsize);
98                         if (!eltbuf || strcmp(elttype, "tree")) {
99                                 if (eltbuf) free(eltbuf);
100                                 return -1;
101                         }
102                         newbase = xmalloc(baselen + 1 + pathlen);
103                         memcpy(newbase, base, baselen);
104                         memcpy(newbase + baselen, path, pathlen);
105                         newbase[baselen + pathlen] = '/';
106                         retval = read_tree_recursive(eltbuf, eltsize,
107                                                      newbase,
108                                                      baselen + pathlen + 1,
109                                                      stage, match);
110                         free(eltbuf);
111                         free(newbase);
112                         if (retval)
113                                 return -1;
114                         continue;
115                 }
116                 if (read_one_entry(sha1, base, baselen, path, mode, stage) < 0)
117                         return -1;
118         }
119         return 0;
120 }
121
122 int read_tree(void *buffer, unsigned long size, int stage, const char **match)
123 {
124         return read_tree_recursive(buffer, size, "", 0, stage, match);
125 }
126
127 struct tree *lookup_tree(const unsigned char *sha1)
128 {
129         struct object *obj = lookup_object(sha1);
130         if (!obj) {
131                 struct tree *ret = xmalloc(sizeof(struct tree));
132                 memset(ret, 0, sizeof(struct tree));
133                 created_object(sha1, &ret->object);
134                 ret->object.type = tree_type;
135                 return ret;
136         }
137         if (!obj->type)
138                 obj->type = tree_type;
139         if (obj->type != tree_type) {
140                 error("Object %s is a %s, not a tree", 
141                       sha1_to_hex(sha1), obj->type);
142                 return NULL;
143         }
144         return (struct tree *) obj;
145 }
146
147 int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
148 {
149         void *bufptr = buffer;
150         struct tree_entry_list **list_p;
151         int n_refs = 0;
152
153         if (item->object.parsed)
154                 return 0;
155         item->object.parsed = 1;
156         list_p = &item->entries;
157         while (size) {
158                 struct object *obj;
159                 struct tree_entry_list *entry;
160                 int len = 1+strlen(bufptr);
161                 unsigned char *file_sha1 = bufptr + len;
162                 char *path = strchr(bufptr, ' ');
163                 unsigned int mode;
164                 if (size < len + 20 || !path || 
165                     sscanf(bufptr, "%o", &mode) != 1)
166                         return -1;
167
168                 entry = xmalloc(sizeof(struct tree_entry_list));
169                 entry->name = strdup(path + 1);
170                 entry->directory = S_ISDIR(mode) != 0;
171                 entry->executable = (mode & S_IXUSR) != 0;
172                 entry->symlink = S_ISLNK(mode) != 0;
173                 entry->zeropad = *(char *)bufptr == '0';
174                 entry->mode = mode;
175                 entry->next = NULL;
176
177                 bufptr += len + 20;
178                 size -= len + 20;
179
180                 if (entry->directory) {
181                         entry->item.tree = lookup_tree(file_sha1);
182                         obj = &entry->item.tree->object;
183                 } else {
184                         entry->item.blob = lookup_blob(file_sha1);
185                         obj = &entry->item.blob->object;
186                 }
187                 if (obj)
188                         n_refs++;
189                 entry->parent = NULL; /* needs to be filled by the user */
190                 *list_p = entry;
191                 list_p = &entry->next;
192         }
193
194         if (track_object_refs) {
195                 struct tree_entry_list *entry;
196                 unsigned i = 0;
197                 struct object_refs *refs = alloc_object_refs(n_refs);
198                 for (entry = item->entries; entry; entry = entry->next)
199                         refs->ref[i++] = entry->item.any;
200                 set_object_refs(&item->object, refs);
201         }
202
203         return 0;
204 }
205
206 int parse_tree(struct tree *item)
207 {
208          char type[20];
209          void *buffer;
210          unsigned long size;
211          int ret;
212
213         if (item->object.parsed)
214                 return 0;
215         buffer = read_sha1_file(item->object.sha1, type, &size);
216         if (!buffer)
217                 return error("Could not read %s",
218                              sha1_to_hex(item->object.sha1));
219         if (strcmp(type, tree_type)) {
220                 free(buffer);
221                 return error("Object %s not a tree",
222                              sha1_to_hex(item->object.sha1));
223         }
224         ret = parse_tree_buffer(item, buffer, size);
225         free(buffer);
226         return ret;
227 }
228
229 struct tree *parse_tree_indirect(const unsigned char *sha1)
230 {
231         struct object *obj = parse_object(sha1);
232         do {
233                 if (!obj)
234                         return NULL;
235                 if (obj->type == tree_type)
236                         return (struct tree *) obj;
237                 else if (obj->type == commit_type)
238                         obj = &(((struct commit *) obj)->tree->object);
239                 else if (obj->type == tag_type)
240                         obj = ((struct tag *) obj)->tagged;
241                 else
242                         return NULL;
243                 if (!obj->parsed)
244                         parse_object(obj->sha1);
245         } while (1);
246 }