view lock.cpp @ 622:695651b8c1a3

added a query hook.  Should compile a run, but I haven't exhaustively tested the various input parameters yet.
As such, there may well be some ways to get to the api calls that bring the module down.
Let me know if you find any.
The actual query call is a bit of a mess, but will be more intuitive from the native python layer (to be written)...
so the python bindings now have a complete path:
	>>import _pyadb
	>>aDB = _pyadb._pyadb_create("test.adb", 0,0,0)
	>>_pyadb._pyadb_status(aDB)
	>>_pyadb._pyadb_insertFromFile(aDB, "someFeats.mfcc12")
		...(add some more data)
	>>result = _pyadb._pyadb_queryFromKey(aDB, "a Key in aDB", [options])

	and then result has a nice dict of your results.

extern "C" {
#include "audioDB_API.h"
}
#include "audioDB-internals.h"

int acquire_lock(int fd, bool exclusive) {
#if !defined(WIN32)
  struct flock lock;
  int status;
  
  lock.l_type = exclusive ? F_WRLCK : F_RDLCK;
  lock.l_whence = SEEK_SET;
  lock.l_start = 0;
  lock.l_len = ADB_HEADER_SIZE;

 retry:
  do {
    status = fcntl(fd, F_SETLKW, &lock);
  } while (status != 0 && errno == EINTR);
  
  if (status) {
    if (errno == EAGAIN) {
      sleep(1);
      goto retry;
    } else {
      return status;
    }
  }
  return 0;
#else
  /* _locking() only supports exclusive locks */
  int status;

 retry:
  status = _locking(fd, _LK_NBLCK, ADB_HEADER_SIZE);
  if(status) {
    Sleep(1000);
    goto retry;
  }
  return 0;
#endif
}

int divest_lock(int fd) {
#if !defined(WIN32)
  struct flock lock;

  lock.l_type = F_UNLCK;
  lock.l_whence = SEEK_SET;
  lock.l_start = 0;
  lock.l_len = ADB_HEADER_SIZE;

  return fcntl(fd, F_SETLKW, &lock);
#else
  return _locking(fd, _LK_UNLCK, ADB_HEADER_SIZE);
#endif
}