mirror of
https://github.com/git/git.git
synced 2024-12-02 06:24:01 +08:00
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
#ifndef PACK_H
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#define PACK_H
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#include "object.h"
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/*
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* Packed object header
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*/
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#define PACK_SIGNATURE 0x5041434b /* "PACK" */
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#define PACK_VERSION 2
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#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
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struct pack_header {
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uint32_t hdr_signature;
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uint32_t hdr_version;
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uint32_t hdr_entries;
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};
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/*
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* Packed object index header
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*
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* struct pack_idx_header {
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* uint32_t idx_signature;
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* uint32_t idx_version;
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* };
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*
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* Note: this header isn't active yet. In future versions of git
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* we may change the index file format. At that time we would start
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* the first four bytes of the new index format with this signature,
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* as all older git binaries would find this value illegal and abort
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* reading the file.
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*
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* This is the case because the number of objects in a packfile
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* cannot exceed 1,431,660,000 as every object would need at least
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* 3 bytes of data and the overall packfile cannot exceed 4 GiB due
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* to the 32 bit offsets used by the index. Clearly the signature
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* exceeds this maximum.
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*
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* Very old git binaries will also compare the first 4 bytes to the
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* next 4 bytes in the index and abort with a "non-monotonic index"
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* error if the second 4 byte word is smaller than the first 4
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* byte word. This would be true in the proposed future index
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* format as idx_signature would be greater than idx_version.
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*/
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#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */
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extern int verify_pack(struct packed_git *, int);
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#define PH_ERROR_EOF (-1)
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#define PH_ERROR_PACK_SIGNATURE (-2)
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#define PH_ERROR_PROTOCOL (-3)
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extern int read_pack_header(int fd, struct pack_header *);
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#endif
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