1 /* Diff output generators and invocation shims. */
2 /*
3  * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 struct diff_input_info {
19 	const char *left_path;
20 	const char *right_path;
21 
22 	/* Set by caller of diff_output_* functions. */
23 	int flags;
24 #define DIFF_INPUT_LEFT_NONEXISTENT	0x00000001
25 #define DIFF_INPUT_RIGHT_NONEXISTENT	0x00000002
26 };
27 
28 struct diff_output_info {
29 	/*
30 	 * Byte offset to each line in the generated output file.
31 	 * The total number of lines in the file is line_offsets.len - 1.
32 	 * The last offset in this array corresponds to end-of-file.
33 	 */
34 	ARRAYLIST(off_t) line_offsets;
35 	/*
36 	 * Type (i.e., context, minus, plus) of each line generated by the diff.
37 	 * nb. 0x00 to 0x3b reserved for client-defined line types.
38 	 */
39 	ARRAYLIST(uint8_t) line_types;
40 #define DIFF_LINE_HUNK		0x3c
41 #define DIFF_LINE_MINUS		0x3d
42 #define DIFF_LINE_PLUS		0x3e
43 #define DIFF_LINE_CONTEXT	0x3f
44 #define DIFF_LINE_NONE		0x40  /* binary or no EOF newline msg, etc. */
45 };
46 
47 void diff_output_info_free(struct diff_output_info *output_info);
48 
49 struct diff_chunk_context {
50 	struct diff_range chunk;
51 	struct diff_range left, right;
52 };
53 
54 int diff_output_plain(struct diff_output_info **output_info, FILE *dest,
55 			const struct diff_input_info *info,
56 			const struct diff_result *result,
57 			int hunk_headers_only);
58 int diff_output_unidiff(struct diff_output_info **output_info,
59 			FILE *dest, const struct diff_input_info *info,
60 			const struct diff_result *result,
61 			unsigned int context_lines);
62 int diff_output_edscript(struct diff_output_info **output_info,
63 			 FILE *dest, const struct diff_input_info *info,
64 			 const struct diff_result *result);
65 int diff_chunk_get_left_start(const struct diff_chunk *c,
66 			      const struct diff_result *r,
67 			      int context_lines);
68 int diff_chunk_get_left_end(const struct diff_chunk *c,
69 			    const struct diff_result *r,
70 			    int context_lines);
71 int diff_chunk_get_right_start(const struct diff_chunk *c,
72 			       const struct diff_result *r,
73 			       int context_lines);
74 int diff_chunk_get_right_end(const struct diff_chunk *c,
75 			     const struct diff_result *r,
76 			     int context_lines);
77 off_t diff_chunk_get_left_start_pos(const struct diff_chunk *c);
78 off_t diff_chunk_get_right_start_pos(const struct diff_chunk *c);
79 struct diff_chunk *diff_chunk_get(const struct diff_result *r, int chunk_idx);
80 int diff_chunk_get_left_count(struct diff_chunk *c);
81 int diff_chunk_get_right_count(struct diff_chunk *c);
82 void diff_chunk_context_get(struct diff_chunk_context *cc,
83 				 const struct diff_result *r,
84 				 int chunk_idx, int context_lines);
85 void diff_chunk_context_load_change(struct diff_chunk_context *cc,
86 				    int *nchunks_used,
87 				    struct diff_result *result,
88 				    int start_chunk_idx,
89 				    int context_lines);
90 
91 struct diff_output_unidiff_state;
92 struct diff_output_unidiff_state *diff_output_unidiff_state_alloc(void);
93 void diff_output_unidiff_state_reset(struct diff_output_unidiff_state *state);
94 void diff_output_unidiff_state_free(struct diff_output_unidiff_state *state);
95 int diff_output_unidiff_chunk(struct diff_output_info **output_info, FILE *dest,
96 			  struct diff_output_unidiff_state *state,
97 			  const struct diff_input_info *info,
98 			  const struct diff_result *result,
99 			  const struct diff_chunk_context *cc);
100 int diff_output_chunk_left_version(struct diff_output_info **output_info,
101 			       FILE *dest,
102 			       const struct diff_input_info *info,
103 			       const struct diff_result *result,
104 			       const struct diff_chunk_context *cc);
105 int diff_output_chunk_right_version(struct diff_output_info **output_info,
106 				FILE *dest,
107 				const struct diff_input_info *info,
108 				const struct diff_result *result,
109 				const struct diff_chunk_context *cc);
110 
111 const char *diff_output_get_label_left(const struct diff_input_info *info);
112 const char *diff_output_get_label_right(const struct diff_input_info *info);