annotate close.cpp @ 402:58b88ab69424 api-inversion

Move the struct adb definition from the auidioDB_API.h into the
audioDB-internals.h header file, leaving only the typedef behind.

Thus a user of the API sees only an incomplete type, which cannot be
instantiated (but /pointers/ to it can); there's then less temptation to
break the abstraction barrier by using structure fields in client code.

Not only that, but we can now safely put C++ stuff in the structure.
Take advantage of this by putting a std::set<std::string> in there, to
hold all the keys currently in the database; populate this field on
audiodb_open() (and delete it on audiodb_close).  This will be useful
when we come to implement variants of audiodb_insert().

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

void audiodb_close(adb_t *adb) {
  free(adb->path);
  free(adb->header);
  delete adb->keys;
  close(adb->fd);
  free(adb);
}