1 #ifndef TREE_WALK_H
2 #define TREE_WALK_H
3
4 #include "cache.h"
5
6 #define MAX_TRAVERSE_TREES 8
7
8 /**
9 * The tree walking API is used to traverse and inspect trees.
10 */
11
12 /**
13 * An entry in a tree. Each entry has a sha1 identifier, pathname, and mode.
14 */
15 struct name_entry {
16 struct object_id oid;
17 const char *path;
18 int pathlen;
19 unsigned int mode;
20 };
21
22 /**
23 * A semi-opaque data structure used to maintain the current state of the walk.
24 */
25 struct tree_desc {
26 /*
27 * pointer into the memory representation of the tree. It always
28 * points at the current entry being visited.
29 */
30 const void *buffer;
31
32 /* points to the current entry being visited. */
33 struct name_entry entry;
34
35 /* counts the number of bytes left in the `buffer`. */
36 unsigned int size;
37 };
38
39 /**
40 * Decode the entry currently being visited (the one pointed to by
41 * `tree_desc's` `entry` member) and return the sha1 of the entry. The
42 * `pathp` and `modep` arguments are set to the entry's pathname and mode
43 * respectively.
44 */
tree_entry_extract(struct tree_desc * desc,const char ** pathp,unsigned short * modep)45 static inline const struct object_id *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned short *modep)
46 {
47 *pathp = desc->entry.path;
48 *modep = desc->entry.mode;
49 return &desc->entry.oid;
50 }
51
52 /**
53 * Calculate the length of a tree entry's pathname. This utilizes the
54 * memory structure of a tree entry to avoid the overhead of using a
55 * generic strlen().
56 */
tree_entry_len(const struct name_entry * ne)57 static inline int tree_entry_len(const struct name_entry *ne)
58 {
59 return ne->pathlen;
60 }
61
62 /*
63 * The _gently versions of these functions warn and return false on a
64 * corrupt tree entry rather than dying,
65 */
66
67 /**
68 * Walk to the next entry in a tree. This is commonly used in conjunction
69 * with `tree_entry_extract` to inspect the current entry.
70 */
71 void update_tree_entry(struct tree_desc *);
72
73 int update_tree_entry_gently(struct tree_desc *);
74
75 /**
76 * Initialize a `tree_desc` and decode its first entry. The buffer and
77 * size parameters are assumed to be the same as the buffer and size
78 * members of `struct tree`.
79 */
80 void init_tree_desc(struct tree_desc *desc, const void *buf, unsigned long size);
81
82 int init_tree_desc_gently(struct tree_desc *desc, const void *buf, unsigned long size);
83
84 /*
85 * Visit the next entry in a tree. Returns 1 when there are more entries
86 * left to visit and 0 when all entries have been visited. This is
87 * commonly used in the test of a while loop.
88 */
89 int tree_entry(struct tree_desc *, struct name_entry *);
90
91 int tree_entry_gently(struct tree_desc *, struct name_entry *);
92
93 /**
94 * Initialize a `tree_desc` and decode its first entry given the
95 * object ID of a tree. Returns the `buffer` member if the latter
96 * is a valid tree identifier and NULL otherwise.
97 */
98 void *fill_tree_descriptor(struct repository *r,
99 struct tree_desc *desc,
100 const struct object_id *oid);
101
102 struct traverse_info;
103 typedef int (*traverse_callback_t)(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *);
104
105 /**
106 * Traverse `n` number of trees in parallel. The `fn` callback member of
107 * `traverse_info` is called once for each tree entry.
108 */
109 int traverse_trees(struct index_state *istate, int n, struct tree_desc *t, struct traverse_info *info);
110
111 enum get_oid_result get_tree_entry_follow_symlinks(struct repository *r, struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned short *mode);
112
113 /**
114 * A structure used to maintain the state of a traversal.
115 */
116 struct traverse_info {
117 const char *traverse_path;
118
119 /*
120 * points to the traverse_info which was used to descend into the
121 * current tree. If this is the top-level tree `prev` will point to
122 * a dummy traverse_info.
123 */
124 struct traverse_info *prev;
125
126 /* is the entry for the current tree (if the tree is a subtree). */
127 const char *name;
128
129 size_t namelen;
130 unsigned mode;
131
132 /* is the length of the full path for the current tree. */
133 size_t pathlen;
134
135 struct pathspec *pathspec;
136
137 /* can be used by callbacks to maintain directory-file conflicts. */
138 unsigned long df_conflicts;
139
140 /* a callback called for each entry in the tree.
141 *
142 * The arguments passed to the traverse callback are as follows:
143 *
144 * - `n` counts the number of trees being traversed.
145 *
146 * - `mask` has its nth bit set if something exists in the nth entry.
147 *
148 * - `dirmask` has its nth bit set if the nth tree's entry is a directory.
149 *
150 * - `entry` is an array of size `n` where the nth entry is from the nth tree.
151 *
152 * - `info` maintains the state of the traversal.
153 *
154 * Returning a negative value will terminate the traversal. Otherwise the
155 * return value is treated as an update mask. If the nth bit is set the nth tree
156 * will be updated and if the bit is not set the nth tree entry will be the
157 * same in the next callback invocation.
158 */
159 traverse_callback_t fn;
160
161 /* can be anything the `fn` callback would want to use. */
162 void *data;
163
164 /* tells whether to stop at the first error or not. */
165 int show_all_errors;
166 };
167
168 /**
169 * Find an entry in a tree given a pathname and the sha1 of a tree to
170 * search. Returns 0 if the entry is found and -1 otherwise. The third
171 * and fourth parameters are set to the entry's sha1 and mode respectively.
172 */
173 int get_tree_entry(struct repository *, const struct object_id *, const char *, struct object_id *, unsigned short *);
174
175 /**
176 * Generate the full pathname of a tree entry based from the root of the
177 * traversal. For example, if the traversal has recursed into another
178 * tree named "bar" the pathname of an entry "baz" in the "bar"
179 * tree would be "bar/baz".
180 */
181 char *make_traverse_path(char *path, size_t pathlen, const struct traverse_info *info,
182 const char *name, size_t namelen);
183
184 /**
185 * Convenience wrapper to `make_traverse_path` into a strbuf.
186 */
187 void strbuf_make_traverse_path(struct strbuf *out,
188 const struct traverse_info *info,
189 const char *name, size_t namelen);
190
191 /**
192 * Initialize a `traverse_info` given the pathname of the tree to start
193 * traversing from.
194 */
195 void setup_traverse_info(struct traverse_info *info, const char *base);
196
197 /**
198 * Calculate the length of a pathname returned by `make_traverse_path`.
199 * This utilizes the memory structure of a tree entry to avoid the
200 * overhead of using a generic strlen().
201 */
traverse_path_len(const struct traverse_info * info,size_t namelen)202 static inline size_t traverse_path_len(const struct traverse_info *info,
203 size_t namelen)
204 {
205 return st_add(info->pathlen, namelen);
206 }
207
208 /* in general, positive means "kind of interesting" */
209 enum interesting {
210 all_entries_not_interesting = -1, /* no, and no subsequent entries will be either */
211 entry_not_interesting = 0,
212 entry_interesting = 1,
213 all_entries_interesting = 2 /* yes, and all subsequent entries will be */
214 };
215
216 enum interesting tree_entry_interesting(struct index_state *istate,
217 const struct name_entry *,
218 struct strbuf *, int,
219 const struct pathspec *ps);
220
221 #endif
222