1 /* Produce ed(1) script output from a diff_result. */
2 /*
3  * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
4  * Copyright (c) 2020 Stefan Sperling <stsp@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <errno.h>
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <stdbool.h>
23 
24 #include <arraylist.h>
25 #include <diff_main.h>
26 #include <diff_output.h>
27 
28 #include "diff_internal.h"
29 
30 static int
31 output_edscript_chunk(struct diff_output_info *outinfo,
32     FILE *dest, const struct diff_input_info *info,
33     const struct diff_result *result,
34     struct diff_chunk_context *cc, enum diff_chunk_type chunk_type)
35 {
36 	off_t outoff = 0, *offp;
37 	int left_start, left_len, right_start, right_len;
38 	int rc;
39 
40 	left_len = cc->left.end - cc->left.start;
41 	if (left_len < 0)
42 		return EINVAL;
43 	else if (left_len == 0 && cc->left.start > 0)
44 		left_start = cc->left.start;
45 	else
46 		left_start = cc->left.start + 1;
47 
48 	right_len = cc->right.end - cc->right.start;
49 	if (right_len < 0)
50 		return EINVAL;
51 	else if (right_len == 0 && cc->right.start > 0)
52 		right_start = cc->right.start;
53 	else
54 		right_start = cc->right.start + 1;
55 
56 	if (chunk_type == CHUNK_MINUS) {
57 		if (left_len == 1) {
58 			rc = fprintf(dest, "%dd%d", left_start, right_start);
59 		} else {
60 			rc = fprintf(dest, "%d,%dd%d\n", left_start,
61 			    cc->left.end, right_start);
62 		}
63 	} else if (chunk_type == CHUNK_PLUS) {
64 		if (right_len == 1) {
65 			rc = fprintf(dest, "%da%d\n", left_start, right_start);
66 		} else {
67 			rc = fprintf(dest, "%da%d,%d\n", left_start,
68 			    right_start, cc->right.end);
69 		}
70 	} else
71 		return EINVAL;
72 
73 	if (rc < 0)
74 		return errno;
75 	if (outinfo) {
76 		ARRAYLIST_ADD(offp, outinfo->line_offsets);
77 		if (offp == NULL)
78 			return ENOMEM;
79 		outoff += rc;
80 		*offp = outoff;
81 	}
82 
83 	return DIFF_RC_OK;
84 }
85 
86 int
87 diff_output_edscript(struct diff_output_info **output_info,
88     FILE *dest, const struct diff_input_info *info,
89     const struct diff_result *result)
90 {
91 	struct diff_output_info *outinfo = NULL;
92 	int i, rc;
93 
94 	if (!result)
95 		return EINVAL;
96 	if (result->rc != DIFF_RC_OK)
97 		return result->rc;
98 
99 	if (output_info) {
100 		*output_info = diff_output_info_alloc();
101 		if (*output_info == NULL)
102 			return ENOMEM;
103 		outinfo = *output_info;
104 	}
105 
106 	for (i = 0; i < result->chunks.len; i++) {
107 		struct diff_chunk *chunk = &result->chunks.head[i];
108 		enum diff_chunk_type t = diff_chunk_type(chunk);
109 		struct diff_chunk_context cc = {};
110 
111 		if (t != CHUNK_MINUS && t != CHUNK_PLUS)
112 			continue;
113 
114 		diff_chunk_context_get(&cc, result, i, 0);
115 
116 		if (diff_range_empty(&cc.chunk))
117 			continue;
118 
119 		rc = output_edscript_chunk(outinfo, dest, info, result, &cc, t);
120 		if (rc != DIFF_RC_OK)
121 			return rc;
122 	}
123 
124 	return DIFF_RC_OK;
125 }