annotate power.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"
}

int audiodb_power(adb_t *adb) {
  /* FIXME: we should probably include in adb_t information about
   * which mode (O_RDONLY|O_RDWR) the database was opened, so that we
   * can check that it's writeable. */
  if(adb->header->length > 0) {
    return 1;
  }

  adb->header->flags |= O2_FLAG_POWER;
  return audiodb_sync_header(adb);
}