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 (result->left.atoms.len == 0)
44 		left_start = 0;
45 	else if (left_len == 0 && cc->left.start > 0)
46 		left_start = cc->left.start;
47 	else
48 		left_start = cc->left.start + 1;
49 
50 	right_len = cc->right.end - cc->right.start;
51 	if (right_len < 0)
52 		return EINVAL;
53 	else if (result->right.atoms.len == 0)
54 		right_start = 0;
55 	else if (right_len == 0 && cc->right.start > 0)
56 		right_start = cc->right.start;
57 	else
58 		right_start = cc->right.start + 1;
59 
60 	if (chunk_type == CHUNK_MINUS) {
61 		if (left_len == 1) {
62 			rc = fprintf(dest, "%dd%d", left_start, right_start);
63 		} else {
64 			rc = fprintf(dest, "%d,%dd%d\n", left_start,
65 			    cc->left.end, right_start);
66 		}
67 	} else if (chunk_type == CHUNK_PLUS) {
68 		if (right_len == 1) {
69 			rc = fprintf(dest, "%da%d\n", left_start, right_start);
70 		} else {
71 			rc = fprintf(dest, "%da%d,%d\n", left_start,
72 			    right_start, cc->right.end);
73 		}
74 	} else
75 		return EINVAL;
76 
77 	if (rc < 0)
78 		return errno;
79 	if (outinfo) {
80 		ARRAYLIST_ADD(offp, outinfo->line_offsets);
81 		if (offp == NULL)
82 			return ENOMEM;
83 		outoff += rc;
84 		*offp = outoff;
85 	}
86 
87 	return DIFF_RC_OK;
88 }
89 
90 int
91 diff_output_edscript(struct diff_output_info **output_info,
92     FILE *dest, const struct diff_input_info *info,
93     const struct diff_result *result)
94 {
95 	struct diff_output_info *outinfo = NULL;
96 	int i, rc;
97 
98 	if (!result)
99 		return EINVAL;
100 	if (result->rc != DIFF_RC_OK)
101 		return result->rc;
102 
103 	if (output_info) {
104 		*output_info = diff_output_info_alloc();
105 		if (*output_info == NULL)
106 			return ENOMEM;
107 		outinfo = *output_info;
108 	}
109 
110 	for (i = 0; i < result->chunks.len; i++) {
111 		struct diff_chunk *chunk = &result->chunks.head[i];
112 		enum diff_chunk_type t = diff_chunk_type(chunk);
113 		struct diff_chunk_context cc = {};
114 
115 		if (t != CHUNK_MINUS && t != CHUNK_PLUS)
116 			continue;
117 
118 		diff_chunk_context_get(&cc, result, i, 0);
119 
120 		if (diff_range_empty(&cc.chunk))
121 			continue;
122 
123 		rc = output_edscript_chunk(outinfo, dest, info, result, &cc, t);
124 		if (rc != DIFF_RC_OK)
125 			return rc;
126 	}
127 
128 	return DIFF_RC_OK;
129 }