6c52614864
It is useful to be able to rewind a check-summed file to a certain previous state after writing data into it using sha1write() API. The fast-import command does this after streaming a blob data to the packfile being generated and then noticing that the same blob has already been written, and it does this with a private code truncate_pack() that is commented as "Yes, this is a layering violation". Introduce two API functions, sha1file_checkpoint(), that allows the caller to save a state of a sha1file, and then later revert it to the saved state. Use it to reimplement truncate_pack(). Signed-off-by: Junio C Hamano <gitster@pobox.com>
43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
#ifndef CSUM_FILE_H
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#define CSUM_FILE_H
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struct progress;
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/* A SHA1-protected file */
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struct sha1file {
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int fd;
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int check_fd;
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unsigned int offset;
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git_SHA_CTX ctx;
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off_t total;
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struct progress *tp;
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const char *name;
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int do_crc;
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uint32_t crc32;
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unsigned char buffer[8192];
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};
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/* Checkpoint */
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struct sha1file_checkpoint {
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off_t offset;
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git_SHA_CTX ctx;
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};
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extern void sha1file_checkpoint(struct sha1file *, struct sha1file_checkpoint *);
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extern int sha1file_truncate(struct sha1file *, struct sha1file_checkpoint *);
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/* sha1close flags */
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#define CSUM_CLOSE 1
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#define CSUM_FSYNC 2
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extern struct sha1file *sha1fd(int fd, const char *name);
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extern struct sha1file *sha1fd_check(const char *name);
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extern struct sha1file *sha1fd_throughput(int fd, const char *name, struct progress *tp);
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extern int sha1close(struct sha1file *, unsigned char *, unsigned int);
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extern int sha1write(struct sha1file *, void *, unsigned int);
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extern void sha1flush(struct sha1file *f);
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extern void crc32_begin(struct sha1file *);
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extern uint32_t crc32_end(struct sha1file *);
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#endif
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