git-commit-vandalism/diffcore.h
Junio C Hamano f345b0a066 [PATCH] Add -B flag to diff-* brothers.
A new diffcore transformation, diffcore-break.c, is introduced.

When the -B flag is given, a patch that represents a complete
rewrite is broken into a deletion followed by a creation.  This
makes it easier to review such a complete rewrite patch.

The -B flag takes the same syntax as the -M and -C flags to
specify the minimum amount of non-source material the resulting
file needs to have to be considered a complete rewrite, and
defaults to 99% if not specified.

As the new test t4008-diff-break-rewrite.sh demonstrates, if a
file is a complete rewrite, it is broken into a delete/create
pair, which can further be subjected to the usual rename
detection if -M or -C is used.  For example, if file0 gets
completely rewritten to make it as if it were rather based on
file1 which itself disappeared, the following happens:

    The original change looks like this:

	file0     --> file0' (quite different from file0)
	file1     --> /dev/null

    After diffcore-break runs, it would become this:

	file0     --> /dev/null
	/dev/null --> file0'
	file1     --> /dev/null

    Then diffcore-rename matches them up:

	file1     --> file0'

The internal score values are finer grained now.  Earlier
maximum of 10000 has been raised to 60000; there is no user
visible changes but there is no reason to waste available bits.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-30 10:35:49 -07:00

94 lines
2.9 KiB
C

/*
* Copyright (C) 2005 Junio C Hamano
*/
#ifndef _DIFFCORE_H_
#define _DIFFCORE_H_
/* This header file is internal between diff.c and its diff transformers
* (e.g. diffcore-rename, diffcore-pickaxe). Never include this header
* in anything else.
*/
#define MAX_SCORE 60000
#define DEFAULT_RENAME_SCORE 30000 /* rename/copy similarity minimum (50%) */
#define DEFAULT_BREAK_SCORE 59400 /* minimum for break to happen (99%)*/
#define RENAME_DST_MATCHED 01
struct diff_filespec {
unsigned char sha1[20];
char *path;
void *data;
unsigned long size;
int xfrm_flags; /* for use by the xfrm */
unsigned short mode; /* file mode */
unsigned sha1_valid : 1; /* if true, use sha1 and trust mode;
* if false, use the name and read from
* the filesystem.
*/
#define DIFF_FILE_VALID(spec) (((spec)->mode) != 0)
unsigned should_free : 1; /* data should be free()'ed */
unsigned should_munmap : 1; /* data should be munmap()'ed */
};
extern struct diff_filespec *alloc_filespec(const char *);
extern void fill_filespec(struct diff_filespec *, const unsigned char *,
unsigned short);
extern int diff_populate_filespec(struct diff_filespec *, int);
extern void diff_free_filespec_data(struct diff_filespec *);
struct diff_filepair {
struct diff_filespec *one;
struct diff_filespec *two;
unsigned short int score;
char status; /* M C R N D U (see Documentation/diff-format.txt) */
unsigned source_stays : 1; /* all of R/C are copies */
unsigned broken_pair : 1;
};
#define DIFF_PAIR_UNMERGED(p) \
(!DIFF_FILE_VALID((p)->one) && !DIFF_FILE_VALID((p)->two))
#define DIFF_PAIR_RENAME(p) (strcmp((p)->one->path, (p)->two->path))
#define DIFF_PAIR_BROKEN(p) \
( (!DIFF_FILE_VALID((p)->one) != !DIFF_FILE_VALID((p)->two)) && \
((p)->broken_pair != 0) )
#define DIFF_PAIR_TYPE_CHANGED(p) \
((S_IFMT & (p)->one->mode) != (S_IFMT & (p)->two->mode))
#define DIFF_PAIR_MODE_CHANGED(p) ((p)->one->mode != (p)->two->mode)
#define DIFF_FILE_CANON_MODE(mode) \
(S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
S_ISLNK(mode) ? S_IFLNK : S_IFDIR)
extern void diff_free_filepair(struct diff_filepair *);
extern int diff_unmodified_pair(struct diff_filepair *);
struct diff_queue_struct {
struct diff_filepair **queue;
int alloc;
int nr;
};
extern struct diff_queue_struct diff_queued_diff;
extern struct diff_filepair *diff_queue(struct diff_queue_struct *,
struct diff_filespec *,
struct diff_filespec *);
extern void diff_q(struct diff_queue_struct *, struct diff_filepair *);
#define DIFF_DEBUG 0
#if DIFF_DEBUG
void diff_debug_filespec(struct diff_filespec *, int, const char *);
void diff_debug_filepair(const struct diff_filepair *, int);
void diff_debug_queue(const char *, struct diff_queue_struct *);
#else
#define diff_debug_filespec(a,b,c) do {} while(0)
#define diff_debug_filepair(a,b) do {} while(0)
#define diff_debug_queue(a,b) do {} while(0)
#endif
#endif