view audioDB-internals.h @ 409:99e6cbad7f76 api-inversion

The lesser of two evils, part 2.

Implement paths through audiodb_insert_datum_internal() for databases
with O2_FLAG_LARGE_ADB, including in some of the helper functions.  Most
of the nasty stuff is concentrated in writing out the paths in what is
now step 6, and everything else looks much as before, apart from a
renumbering of the steps taken.

Now we can implement audiodb_insert() for O2_FLAG_LARGE_ADB databases;
we need to construct an adb_datum_internal_t from our adb_insert_t, but
that's straightforward -- even just about straightforward enough to do
it inline.

Then audioDB::batchinsert() can be rewritten completely in terms of API
functions, and doesn't need any kind of special treatment for the large
case.  Hooray.  The real point of that is of course that we can now
delete wodges of dead code, and move out audioDB::insert and
audioDB::batchinsert into audioDB.cpp, because all they're doing now is
dealing with command-line logic.

This point marks the limit of what can be achieved in terms of "API
inversion" at this time; the only remaining function,
audiodb_query() / audioDB::query cannot be inverted because its
API implementation is incomplete.

Future plans, in some order:
- merge this branch to trunk (check with current API/ABI clients);
- complete audiodb_query() implementation;
- invert audioDB::query / audiodb_query();
- MORE TESTS;
- remove audioDB.cpp from list of files compiled into the library;
- implement missing API functions (index, liszt, sample) directly;
- source code rearrangement into library and command-line directories;
- include bindings to library for some plausible candidate environments
  (Perl, Python, Lisp, Pd, Max/MSP) as examples;
- API documentation.

typedef struct adb_datum_internal {
  uint32_t nvectors;
  uint32_t dim;
  const char *key;
  void *data;
  void *times;
  void *power;
} adb_datum_internal_t;

struct adb {
  char *path;
  int fd;
  int flags;
  adb_header_t *header;
  std::set<std::string> *keys;
};

/* We could go gcc-specific here and use typeof() instead of passing
 * in an explicit type.  Answers on a postcard as to whether that's a
 * good plan or not. */
#define mmap_or_goto_error(type, var, start, length) \
  { void *tmp = mmap(0, length, PROT_READ, MAP_SHARED, adb->fd, (start)); \
    if(tmp == (void *) -1) { \
      goto error; \
    } \
    var = (type) tmp; \
  }

#define maybe_munmap(table, length) \
  { if(table) { \
      munmap(table, length); \
    } \
  }

static inline int audiodb_sync_header(adb_t *adb) {
  off_t pos;
  pos = lseek(adb->fd, (off_t) 0, SEEK_CUR);
  if(pos == (off_t) -1) {
    goto error;
  }
  if(lseek(adb->fd, (off_t) 0, SEEK_SET) == (off_t) -1) {
    goto error;
  }
  if(write(adb->fd, adb->header, O2_HEADERSIZE) != O2_HEADERSIZE) {
    goto error;
  }

  /* can be fsync() if fdatasync() is racily exciting and new */
  fdatasync(adb->fd);
  if(lseek(adb->fd, pos, SEEK_SET) == (off_t) -1) {
    goto error;
  }
  return 0;

 error:
  return 1;
}