8ef50d9958
This patch prepares for callers to be able to write reverse index files to disk. It adds the necessary machinery to write a format-compliant .rev file from within 'write_rev_file()', which is called from 'finish_tmp_packfile()'. Similar to the process by which the reverse index is computed in memory, these new paths also have to sort a list of objects by their offsets within a packfile. These new paths use a qsort() (as opposed to a radix sort), since our specialized radix sort requires a full revindex_entry struct per object, which is more memory than we need to allocate. The qsort is obviously slower, but the theoretical slowdown would require a repository with a large amount of objects, likely implying that the time spent in, say, pack-objects during a repack would dominate the overall runtime. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
115 lines
3.6 KiB
C
115 lines
3.6 KiB
C
#ifndef PACK_H
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#define PACK_H
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#include "object.h"
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#include "csum-file.h"
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struct repository;
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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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* The first four bytes of index formats later than version 1 should
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* start with this signature, as all older git binaries would find this
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* value illegal and abort 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 with
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* version 1 of the index file due to the offsets limited to 32 bits.
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* Clearly the signature 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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struct pack_idx_option {
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unsigned flags;
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/* flag bits */
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#define WRITE_IDX_VERIFY 01 /* verify only, do not write the idx file */
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#define WRITE_IDX_STRICT 02
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#define WRITE_REV 04
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#define WRITE_REV_VERIFY 010
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uint32_t version;
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uint32_t off32_limit;
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/*
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* List of offsets that would fit within off32_limit but
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* need to be written out as 64-bit entity for byte-for-byte
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* verification.
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*/
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int anomaly_alloc, anomaly_nr;
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uint32_t *anomaly;
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};
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void reset_pack_idx_option(struct pack_idx_option *);
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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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* Common part of object structure used for write_idx_file
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*/
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struct pack_idx_entry {
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struct object_id oid;
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uint32_t crc32;
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off_t offset;
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};
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struct progress;
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/* Note, the data argument could be NULL if object type is blob */
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typedef int (*verify_fn)(const struct object_id *, enum object_type, unsigned long, void*, int*);
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const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, const unsigned char *sha1);
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int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
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int verify_pack_index(struct packed_git *);
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int verify_pack(struct repository *, struct packed_git *, verify_fn fn, struct progress *, uint32_t);
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off_t write_pack_header(struct hashfile *f, uint32_t);
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void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
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char *index_pack_lockfile(int fd);
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struct ref;
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void write_promisor_file(const char *promisor_name, struct ref **sought, int nr_sought);
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const char *write_rev_file(const char *rev_name, struct pack_idx_entry **objects, uint32_t nr_objects, const unsigned char *hash, unsigned flags);
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/*
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* The "hdr" output buffer should be at least this big, which will handle sizes
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* up to 2^67.
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*/
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#define MAX_PACK_OBJECT_HEADER 10
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int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
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enum object_type, uintmax_t);
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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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int read_pack_header(int fd, struct pack_header *);
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struct hashfile *create_tmp_packfile(char **pack_tmp_name);
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void finish_tmp_packfile(struct strbuf *name_buffer, const char *pack_tmp_name, struct pack_idx_entry **written_list, uint32_t nr_written, struct pack_idx_option *pack_idx_opts, unsigned char sha1[]);
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#endif
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