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Date:: Tue Aug 29 13:18:21 2023 UTC
Message:: back out "improve accuracy of function prototype in hunk headers" which was commit 8993f42562696079866fc2dec7191877b6cc1f18 This commit introduced a regression where hunk headers would contain lines taken from below or within a change. Reported by tb@ and sthen@. There is some confusion around how the -p feature was documented: -p With unified and context diffs, show with each change the first 40 characters of the last line before the context beginning with a letter, an underscore or a dollar sign. For C source code following standard layout conventions, this will show the prototype of the function the change applies to. The original behaviour matches "the last line before the context beginning with a letter ...". The new (reverted) behaviour sometimes matches "will show the prototype of the function the change applies to". This did always happen as intended, as seen when some .c files in the OpenBSD src tree were changed. The new behaviour was also worse for Makefiles in the OpenBSD ports tree. Let's revert to the traditional -p behaviour until a better fix is found. Details: https://marc.gameoftrees.org/mail/1692696001.69872_0.html https://marc.info/?l=gameoftrees&m=169269624516330&w=2 ok tb@
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  1 85ab4559 2020-09-22 stsp /* Generic infrastructure to implement various diff algorithms. */
  2 85ab4559 2020-09-22 stsp /*
  3 85ab4559 2020-09-22 stsp  * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
  4 85ab4559 2020-09-22 stsp  *
  5 85ab4559 2020-09-22 stsp  * Permission to use, copy, modify, and distribute this software for any
  6 85ab4559 2020-09-22 stsp  * purpose with or without fee is hereby granted, provided that the above
  7 85ab4559 2020-09-22 stsp  * copyright notice and this permission notice appear in all copies.
  8 85ab4559 2020-09-22 stsp  *
  9 85ab4559 2020-09-22 stsp  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 10 85ab4559 2020-09-22 stsp  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 11 85ab4559 2020-09-22 stsp  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 12 85ab4559 2020-09-22 stsp  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 13 85ab4559 2020-09-22 stsp  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 14 85ab4559 2020-09-22 stsp  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 15 85ab4559 2020-09-22 stsp  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 16 85ab4559 2020-09-22 stsp  */
 17 85ab4559 2020-09-22 stsp 
 18 85ab4559 2020-09-22 stsp #ifndef MAX
 19 85ab4559 2020-09-22 stsp #define MAX(A,B) ((A)>(B)?(A):(B))
 20 85ab4559 2020-09-22 stsp #endif
 21 85ab4559 2020-09-22 stsp #ifndef MIN
 22 85ab4559 2020-09-22 stsp #define MIN(A,B) ((A)<(B)?(A):(B))
 23 85ab4559 2020-09-22 stsp #endif
 24 85ab4559 2020-09-22 stsp 
 25 85ab4559 2020-09-22 stsp static inline bool
 26 85ab4559 2020-09-22 stsp diff_range_empty(const struct diff_range *r)
 27 85ab4559 2020-09-22 stsp {
 28 85ab4559 2020-09-22 stsp 	return r->start == r->end;
 29 85ab4559 2020-09-22 stsp }
 30 85ab4559 2020-09-22 stsp 
 31 85ab4559 2020-09-22 stsp static inline bool
 32 85ab4559 2020-09-22 stsp diff_ranges_touch(const struct diff_range *a, const struct diff_range *b)
 33 85ab4559 2020-09-22 stsp {
 34 85ab4559 2020-09-22 stsp 	return (a->end >= b->start) && (a->start <= b->end);
 35 85ab4559 2020-09-22 stsp }
 36 85ab4559 2020-09-22 stsp 
 37 85ab4559 2020-09-22 stsp static inline void
 38 85ab4559 2020-09-22 stsp diff_ranges_merge(struct diff_range *a, const struct diff_range *b)
 39 85ab4559 2020-09-22 stsp {
 40 85ab4559 2020-09-22 stsp 	*a = (struct diff_range){
 41 85ab4559 2020-09-22 stsp 		.start = MIN(a->start, b->start),
 42 85ab4559 2020-09-22 stsp 		.end = MAX(a->end, b->end),
 43 85ab4559 2020-09-22 stsp 	};
 44 85ab4559 2020-09-22 stsp }
 45 85ab4559 2020-09-22 stsp 
 46 85ab4559 2020-09-22 stsp static inline int
 47 85ab4559 2020-09-22 stsp diff_range_len(const struct diff_range *r)
 48 85ab4559 2020-09-22 stsp {
 49 85ab4559 2020-09-22 stsp 	if (!r)
 50 85ab4559 2020-09-22 stsp 		return 0;
 51 85ab4559 2020-09-22 stsp 	return r->end - r->start;
 52 85ab4559 2020-09-22 stsp }
 53 85ab4559 2020-09-22 stsp 
 54 85ab4559 2020-09-22 stsp /* Indicate whether two given diff atoms match. */
 55 85ab4559 2020-09-22 stsp int
 56 85ab4559 2020-09-22 stsp diff_atom_same(bool *same,
 57 85ab4559 2020-09-22 stsp 	       const struct diff_atom *left,
 58 85ab4559 2020-09-22 stsp 	       const struct diff_atom *right);
 59 85ab4559 2020-09-22 stsp 
 60 85ab4559 2020-09-22 stsp /* A diff chunk represents a set of atoms on the left and/or a set of atoms on
 61 85ab4559 2020-09-22 stsp  * the right.
 62 85ab4559 2020-09-22 stsp  *
 63 85ab4559 2020-09-22 stsp  * If solved == false:
 64 85ab4559 2020-09-22 stsp  * The diff algorithm has divided the source file, and this is a chunk that the
 65 85ab4559 2020-09-22 stsp  * inner_algo should run on next.
 66 85ab4559 2020-09-22 stsp  * The lines on the left should be diffed against the lines on the right.
 67 85ab4559 2020-09-22 stsp  * (If there are no left lines or no right lines, it implies solved == true,
 68 85ab4559 2020-09-22 stsp  * because there is nothing to diff.)
 69 85ab4559 2020-09-22 stsp  *
 70 85ab4559 2020-09-22 stsp  * If solved == true:
 71 85ab4559 2020-09-22 stsp  * If there are only left atoms, it is a chunk removing atoms from the left ("a
 72 85ab4559 2020-09-22 stsp  * minus chunk").
 73 85ab4559 2020-09-22 stsp  * If there are only right atoms, it is a chunk adding atoms from the right ("a
 74 85ab4559 2020-09-22 stsp  * plus chunk").
 75 85ab4559 2020-09-22 stsp  * If there are both left and right lines, it is a chunk of equal content on
 76 85ab4559 2020-09-22 stsp  * both sides, and left_count == right_count:
 77 85ab4559 2020-09-22 stsp  *
 78 85ab4559 2020-09-22 stsp  * - foo  }
 79 85ab4559 2020-09-22 stsp  * - bar  }-- diff_chunk{ left_start = &left.atoms.head[0], left_count = 3,
 80 85ab4559 2020-09-22 stsp  * - baz  }               right_start = NULL, right_count = 0 }
 81 85ab4559 2020-09-22 stsp  *   moo    }
 82 85ab4559 2020-09-22 stsp  *   goo    }-- diff_chunk{ left_start = &left.atoms.head[3], left_count = 3,
 83 85ab4559 2020-09-22 stsp  *   zoo    }              right_start = &right.atoms.head[0], right_count = 3 }
 84 85ab4559 2020-09-22 stsp  *  +loo      }
 85 85ab4559 2020-09-22 stsp  *  +roo      }-- diff_chunk{ left_start = NULL, left_count = 0,
 86 85ab4559 2020-09-22 stsp  *  +too      }            right_start = &right.atoms.head[3], right_count = 3 }
 87 85ab4559 2020-09-22 stsp  *
 88 85ab4559 2020-09-22 stsp  */
 89 85ab4559 2020-09-22 stsp struct diff_chunk {
 90 85ab4559 2020-09-22 stsp 	bool solved;
 91 85ab4559 2020-09-22 stsp 	struct diff_atom *left_start;
 92 85ab4559 2020-09-22 stsp 	unsigned int left_count;
 93 85ab4559 2020-09-22 stsp 	struct diff_atom *right_start;
 94 85ab4559 2020-09-22 stsp 	unsigned int right_count;
 95 85ab4559 2020-09-22 stsp };
 96 85ab4559 2020-09-22 stsp 
 97 85ab4559 2020-09-22 stsp #define DIFF_RESULT_ALLOC_BLOCKSIZE 128
 98 85ab4559 2020-09-22 stsp 
 99 2f26640c 2020-10-17 stsp struct diff_chunk_context;
100 2f26640c 2020-10-17 stsp 
101 2f26640c 2020-10-17 stsp bool
102 2f26640c 2020-10-17 stsp diff_chunk_context_empty(const struct diff_chunk_context *cc);
103 2f26640c 2020-10-17 stsp 
104 2f26640c 2020-10-17 stsp bool
105 2f26640c 2020-10-17 stsp diff_chunk_contexts_touch(const struct diff_chunk_context *cc,
106 2f26640c 2020-10-17 stsp 			  const struct diff_chunk_context *other);
107 2f26640c 2020-10-17 stsp 
108 2f26640c 2020-10-17 stsp void
109 2f26640c 2020-10-17 stsp diff_chunk_contexts_merge(struct diff_chunk_context *cc,
110 2f26640c 2020-10-17 stsp 			  const struct diff_chunk_context *other);
111 2f26640c 2020-10-17 stsp 
112 85ab4559 2020-09-22 stsp struct diff_state {
113 85ab4559 2020-09-22 stsp 	/* The final result passed to the original diff caller. */
114 85ab4559 2020-09-22 stsp 	struct diff_result *result;
115 85ab4559 2020-09-22 stsp 
116 85ab4559 2020-09-22 stsp 	/* The root diff_data is in result->left,right, these are (possibly)
117 85ab4559 2020-09-22 stsp 	 * subsections of the root data. */
118 85ab4559 2020-09-22 stsp 	struct diff_data left;
119 85ab4559 2020-09-22 stsp 	struct diff_data right;
120 85ab4559 2020-09-22 stsp 
121 85ab4559 2020-09-22 stsp 	unsigned int recursion_depth_left;
122 85ab4559 2020-09-22 stsp 
123 85ab4559 2020-09-22 stsp 	/* Remaining chunks from one diff algorithm pass, if any solved == false
124 85ab4559 2020-09-22 stsp 	 * chunks came up. */
125 85ab4559 2020-09-22 stsp 	diff_chunk_arraylist_t temp_result;
126 8be88dfa 2020-10-21 stsp 
127 8be88dfa 2020-10-21 stsp  	/* State buffer used by Myers algorithm. */
128 8be88dfa 2020-10-21 stsp 	int *kd_buf;
129 8be88dfa 2020-10-21 stsp 	size_t kd_buf_size; /* in units of sizeof(int), not bytes */
130 85ab4559 2020-09-22 stsp };
131 85ab4559 2020-09-22 stsp 
132 85ab4559 2020-09-22 stsp struct diff_chunk *diff_state_add_chunk(struct diff_state *state, bool solved,
133 85ab4559 2020-09-22 stsp 					struct diff_atom *left_start,
134 85ab4559 2020-09-22 stsp 					unsigned int left_count,
135 85ab4559 2020-09-22 stsp 					struct diff_atom *right_start,
136 85ab4559 2020-09-22 stsp 					unsigned int right_count);
137 2c20a3ed 2020-09-22 stsp 
138 2c20a3ed 2020-09-22 stsp struct diff_output_info;
139 2c20a3ed 2020-09-22 stsp 
140 2c20a3ed 2020-09-22 stsp int diff_output_lines(struct diff_output_info *output_info, FILE *dest,
141 2c20a3ed 2020-09-22 stsp 		       const char *prefix, struct diff_atom *start_atom,
142 2c20a3ed 2020-09-22 stsp 		       unsigned int count);
143 2c20a3ed 2020-09-22 stsp 
144 7021523c 2020-10-16 stsp int diff_output_trailing_newline_msg(struct diff_output_info *outinfo,
145 7021523c 2020-10-16 stsp 				     FILE *dest,
146 7021523c 2020-10-16 stsp 				     const struct diff_chunk *c);
147 b3fd1fa2 2020-12-10 stsp #define DIFF_FUNCTION_CONTEXT_SIZE	55
148 b3fd1fa2 2020-12-10 stsp int diff_output_match_function_prototype(char *prototype, size_t prototype_size,
149 b3fd1fa2 2020-12-10 stsp 					 int *last_prototype_idx,
150 13e2caa3 2020-10-17 stsp 					 const struct diff_result *result,
151 dc306c6b 2023-08-29 stsp 					 const struct diff_chunk_context *cc);
152 7021523c 2020-10-16 stsp 
153 2c20a3ed 2020-09-22 stsp struct diff_output_info *diff_output_info_alloc(void);
154 87c31341 2020-10-11 neels 
155 87c31341 2020-10-11 neels void
156 87c31341 2020-10-11 neels diff_data_init_subsection(struct diff_data *d, struct diff_data *parent,
157 87c31341 2020-10-11 neels 			  struct diff_atom *from_atom, unsigned int atoms_count);