csum-file.h

   1 #ifndef CSUM_FILE_H
   2 #define CSUM_FILE_H
   3
   4 #include "hash.h"
   5 #include "write-or-die.h"
   6
   7 struct progress;
   8
   9 /* A SHA1-protected file */
  10 struct hashfile {
  11         int fd;
  12         int check_fd;
  13         unsigned int offset;
  14         git_hash_ctx ctx;
  15         off_t total;
  16         struct progress *tp;
  17         const char *name;
  18         int do_crc;
  19         uint32_t crc32;
  20         size_t buffer_len;
  21         unsigned char *buffer;
  22         unsigned char *check_buffer;
  23
  24         /**
  25          * If non-zero, skip_hash indicates that we should
  26          * not actually compute the hash for this hashfile and
  27          * instead only use it as a buffered write.
  28          */
  29         int skip_hash;
  30 };
  31
  32 /* Checkpoint */
  33 struct hashfile_checkpoint {
  34         off_t offset;
  35         git_hash_ctx ctx;
  36 };
  37
  38 void hashfile_checkpoint(struct hashfile *, struct hashfile_checkpoint *);
  39 int hashfile_truncate(struct hashfile *, struct hashfile_checkpoint *);
  40
  41 /* finalize_hashfile flags */
  42 #define CSUM_CLOSE              1
  43 #define CSUM_FSYNC              2
  44 #define CSUM_HASH_IN_STREAM     4
  45
  46 struct hashfile *hashfd(int fd, const char *name);
  47 struct hashfile *hashfd_check(const char *name);
  48 struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp);
  49
  50 /*
  51  * Free the hashfile without flushing its contents to disk. This only
  52  * needs to be called when not calling `finalize_hashfile()`.
  53  */
  54 void free_hashfile(struct hashfile *f);
  55
  56 /*
  57  * Finalize the hashfile by flushing data to disk and free'ing it.
  58  */
  59 int finalize_hashfile(struct hashfile *, unsigned char *, enum fsync_component, unsigned int);
  60 void discard_hashfile(struct hashfile *);
  61 void hashwrite(struct hashfile *, const void *, unsigned int);
  62 void hashflush(struct hashfile *f);
  63 void crc32_begin(struct hashfile *);
  64 uint32_t crc32_end(struct hashfile *);
  65
  66 /* Verify checksum validity while reading. Returns non-zero on success. */
  67 int hashfile_checksum_valid(const unsigned char *data, size_t len);
  68
  69 /*
  70  * Returns the total number of bytes fed to the hashfile so far (including ones
  71  * that have not been written out to the descriptor yet).
  72  */
  73 static inline off_t hashfile_total(struct hashfile *f)
  74 {
  75         return f->total + f->offset;
  76 }
  77
  78 static inline void hashwrite_u8(struct hashfile *f, uint8_t data)
  79 {
  80         hashwrite(f, &data, sizeof(data));
  81 }
  82
  83 static inline void hashwrite_be32(struct hashfile *f, uint32_t data)
  84 {
  85         data = htonl(data);
  86         hashwrite(f, &data, sizeof(data));
  87 }
  88
  89 static inline size_t hashwrite_be64(struct hashfile *f, uint64_t data)
  90 {
  91         data = htonll(data);
  92         hashwrite(f, &data, sizeof(data));
  93         return sizeof(data);
  94 }
  95
  96 #endif