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         struct 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         const struct git_hash_algo *algop;
  24
  25         /**
  26          * If non-zero, skip_hash indicates that we should
  27          * not actually compute the hash for this hashfile and
  28          * instead only use it as a buffered write.
  29          */
  30         int skip_hash;
  31 };
  32
  33 /* Checkpoint */
  34 struct hashfile_checkpoint {
  35         off_t offset;
  36         struct git_hash_ctx ctx;
  37 };
  38
  39 void hashfile_checkpoint_init(struct hashfile *, struct hashfile_checkpoint *);
  40 void hashfile_checkpoint(struct hashfile *, struct hashfile_checkpoint *);
  41 int hashfile_truncate(struct hashfile *, struct hashfile_checkpoint *);
  42
  43 /* finalize_hashfile flags */
  44 #define CSUM_CLOSE              1
  45 #define CSUM_FSYNC              2
  46 #define CSUM_HASH_IN_STREAM     4
  47
  48 struct hashfile *hashfd(const struct git_hash_algo *algop,
  49                         int fd, const char *name);
  50 struct hashfile *hashfd_check(const struct git_hash_algo *algop,
  51                               const char *name);
  52 struct hashfile *hashfd_throughput(const struct git_hash_algo *algop,
  53                                    int fd, const char *name, struct progress *tp);
  54
  55 /*
  56  * Free the hashfile without flushing its contents to disk. This only
  57  * needs to be called when not calling `finalize_hashfile()`.
  58  */
  59 void free_hashfile(struct hashfile *f);
  60
  61 /*
  62  * Finalize the hashfile by flushing data to disk and free'ing it.
  63  */
  64 int finalize_hashfile(struct hashfile *, unsigned char *, enum fsync_component, unsigned int);
  65 void discard_hashfile(struct hashfile *);
  66 void hashwrite(struct hashfile *, const void *, unsigned int);
  67 void hashflush(struct hashfile *f);
  68 void crc32_begin(struct hashfile *);
  69 uint32_t crc32_end(struct hashfile *);
  70
  71 /* Verify checksum validity while reading. Returns non-zero on success. */
  72 int hashfile_checksum_valid(const struct git_hash_algo *algop,
  73                             const unsigned char *data, size_t len);
  74
  75 /*
  76  * Returns the total number of bytes fed to the hashfile so far (including ones
  77  * that have not been written out to the descriptor yet).
  78  */
  79 static inline off_t hashfile_total(struct hashfile *f)
  80 {
  81         return f->total + f->offset;
  82 }
  83
  84 static inline void hashwrite_u8(struct hashfile *f, uint8_t data)
  85 {
  86         hashwrite(f, &data, sizeof(data));
  87 }
  88
  89 static inline void hashwrite_be32(struct hashfile *f, uint32_t data)
  90 {
  91         data = htonl(data);
  92         hashwrite(f, &data, sizeof(data));
  93 }
  94
  95 static inline size_t hashwrite_be64(struct hashfile *f, uint64_t data)
  96 {
  97         data = htonll(data);
  98         hashwrite(f, &data, sizeof(data));
  99         return sizeof(data);
 100 }
 101
 102 #endif