1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
18  * Compute the differences between two blobs and write unified diff text
19  * to the provided output FILE. Two const char * diff header labels may
20  * be provided which will be used to identify each blob in the diff output.
21  * If a label is NULL, use the blob's SHA1 checksum instead.
22  * The number of context lines to show in the diff must be specified as well.
23  * Whitespace differences may optionally be ignored.
24  * If not NULL, the two initial output arguments will be populated with an
25  * array of line offsets for, and the number of lines in, the unidiff text.
26  */
27 const struct got_error *got_diff_blob(off_t **, size_t *,
28     struct got_blob_object *, struct got_blob_object *,
29     const char *, const char *, int, int, FILE *);
30 
31 /*
32  * Compute the differences between a blob and a file and write unified diff
33  * text to the provided output file. The file's size must be provided, as
34  * well as a const char * diff header label which identifies the file.
35  * An optional const char * diff header label for the blob may be provided, too.
36  * The number of context lines to show in the diff must be specified as well.
37  * Whitespace differences may optionally be ignored.
38  */
39 const struct got_error *got_diff_blob_file(struct got_blob_object *,
40     const char *, FILE *, size_t, const char *, int, int, FILE *);
41 
42 /*
43  * A callback function invoked to handle the differences between two blobs
44  * when diffing trees with got_diff_tree(). This callback receives two blobs,
45  * their respective IDs, and two corresponding paths within the diffed trees.
46  * The first blob contains content from the old side of the diff, and
47  * the second blob contains content on the new side of the diff.
48  * The set of arguments relating to either blob may be NULL to indicate
49  * that no content is present on its respective side of the diff.
50  * File modes from relevant tree objects which contain the blobs may
51  * also be passed. These will be zero if not available.
52  */
53 typedef const struct got_error *(*got_diff_blob_cb)(void *,
54     struct got_blob_object *, struct got_blob_object *,
55     struct got_object_id *, struct got_object_id *,
56     const char *, const char *, mode_t, mode_t, struct got_repository *);
57 
58 /*
59  * A pre-defined implementation of got_diff_blob_cb() which appends unidiff
60  * output to a file. The caller must allocate and fill in the argument
61  * structure.
62  */
63 struct got_diff_blob_output_unidiff_arg {
64 	FILE *outfile;		/* Unidiff text will be written here. */
65 	int diff_context;	/* Sets the number of context lines. */
66 	int ignore_whitespace;	/* Ignore whitespace differences. */
67 
68 	/*
69 	 * The number of lines contained in produced unidiff text output,
70 	 * and an array of byte offsets to each line. May be initialized to
71 	 * zero and NULL to ignore line offsets. If not NULL, then the line
72 	 * offsets array will be populated. Optionally, the array can be
73 	 * pre-populated with line offsets, with nlines > 0 indicating
74 	 * the length of the pre-populated array. This is useful if the
75 	 * output file already contains some lines of text.
76 	 * The array will be grown as needed to accomodate additional line
77 	 * offsets, and the last offset found in a pre-populated array will
78 	 * be added to all subsequent offsets.
79 	 */
80 	size_t nlines;
81 	off_t *line_offsets;	/* Dispose of with free(3) when done. */
82 };
83 const struct got_error *got_diff_blob_output_unidiff(void *,
84     struct got_blob_object *, struct got_blob_object *,
85     struct got_object_id *, struct got_object_id *,
86     const char *, const char *, mode_t, mode_t, struct got_repository *);
87 
88 /*
89  * Compute the differences between two trees and invoke the provided
90  * got_diff_blob_cb() callback when content differs.
91  * Diffing of blob content can be suppressed by passing zero for the
92  * 'diff_content' parameter. The callback will then only receive blob
93  * object IDs and diff labels, but NULL pointers instead of blob objects.
94  */
95 const struct got_error *got_diff_tree(struct got_tree_object *,
96     struct got_tree_object *, const char *, const char *,
97     struct got_repository *, got_diff_blob_cb cb, void *cb_arg, int);
98 
99 /*
100  * A pre-defined implementation of got_diff_blob_cb() which collects a list
101  * of file paths that differ between two trees.
102  * The caller must allocate and initialize a got_pathlist_head * argument.
103  * Data pointers of entries added to the path list will point to a struct
104  * got_diff_changed_path object.
105  * The caller is expected to free both the path and data pointers of all
106  * entries on the path list.
107  */
108 struct got_diff_changed_path {
109 	/*
110 	 * The modification status of this path. It can be GOT_STATUS_ADD,
111 	 * GOT_STATUS_DELETE, GOT_STATUS_MODIFY, or GOT_STATUS_MODE_CHANGE.
112 	 */
113 	int status;
114 };
115 const struct got_error *got_diff_tree_collect_changed_paths(void *,
116     struct got_blob_object *, struct got_blob_object *,
117     struct got_object_id *, struct got_object_id *,
118     const char *, const char *, mode_t, mode_t, struct got_repository *);
119 
120 /*
121  * Diff two objects, assuming both objects are blobs. Two const char * diff
122  * header labels may be provided which will be used to identify each blob in
123  * the diff output. If a label is NULL, use the blob's SHA1 checksum instead.
124  * The number of context lines to show in the diff must be specified as well.
125  * Write unified diff text to the provided output FILE.
126  * If not NULL, the two initial output arguments will be populated with an
127  * array of line offsets for, and the number of lines in, the unidiff text.
128  */
129 const struct got_error *got_diff_objects_as_blobs(off_t **, size_t *,
130     struct got_object_id *, struct got_object_id *,
131     const char *, const char *, int, int,
132     struct got_repository *, FILE *);
133 
134 /*
135  * Diff two objects, assuming both objects are trees. Two const char * diff
136  * header labels may be provided which will be used to identify each blob in
137  * the trees. If a label is NULL, use the blob's SHA1 checksum instead.
138  * The number of context lines to show in diffs must be specified.
139  * Write unified diff text to the provided output FILE.
140  * If not NULL, the two initial output arguments will be populated with an
141  * array of line offsets for, and the number of lines in, the unidiff text.
142  */
143 const struct got_error *got_diff_objects_as_trees(off_t **, size_t *,
144     struct got_object_id *, struct got_object_id *, char *, char *,
145     int, int, struct got_repository *, FILE *);
146 
147 /*
148  * Diff two objects, assuming both objects are commits.
149  * The number of context lines to show in diffs must be specified.
150  * Write unified diff text to the provided output FILE.
151  * If not NULL, the two initial output arguments will be populated with an
152  * array of line offsets for, and the number of lines in, the unidiff text.
153  */
154 const struct got_error *got_diff_objects_as_commits(off_t **, size_t *,
155     struct got_object_id *, struct got_object_id *, int, int,
156     struct got_repository *, FILE *);
157 
158 #define GOT_DIFF_MAX_CONTEXT	64