SQLiteUtils.cpp

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/*
 * SPDX-License-Identifier: GPL-2.0-or-later
 * SPDX-FileName: SQLiteUtils.cpp
 * SPDX-FileContributor: Dmitry Vedenko
 */
 
#include "SQLiteUtils.h"
 
#include "sqlite3.h"
 
namespace audacity::sqlite
{
namespace
{
// This singleton handles initialization/shutdown of the SQLite library.
// It is needed because our local SQLite is built with SQLITE_OMIT_AUTOINIT
// defined.
//
// It's safe to use even if a system version of SQLite is used that didn't
// have SQLITE_OMIT_AUTOINIT defined.
class SQLiteIniter
{
public:
   SQLiteIniter()
   {
      // Enable URI filenames for all connections
      mError = Error(sqlite3_config(SQLITE_CONFIG_URI, 1));
 
      if (mError.IsError())
         return;
 
      mError =
         Error(sqlite3_config(SQLITE_CONFIG_LOG, SQLiteLogCallback, this));
 
      if (mError.IsError())
         return;
 
      mError = Error(sqlite3_initialize());
 
#ifdef NO_SHM
      if (mError.IsError())
         return;
 
      // Use the "unix-excl" VFS to make access to the DB exclusive.  This
      // gets rid of the "<database name>-shm" shared memory file.
      //
      // Though it shouldn't, it doesn't matter if this fails.
      auto vfs = sqlite3_vfs_find("unix-excl");
      if (vfs)
         sqlite3_vfs_register(vfs, 1);
#endif
   }
 
   ~SQLiteIniter()
   {
      // This function must be called single-threaded only
      // It returns a value, but there's nothing we can do with it
      (void)sqlite3_shutdown();
   }
 
   static void SQLiteLogCallback(void* initer, int code, const char* msg)
   {
      SQLiteIniter* self = static_cast<SQLiteIniter*>(initer);
 
      if (self->mLogCallback)
         self->mLogCallback(code, msg);
   }
 
   Error GetError() const noexcept
   {
      return mError;
   }
 
   void SetLogCallback (LogCallback callback)
   {
      mLogCallback = std::move(callback);
   }
 
private:
   Error mError;
   LogCallback mLogCallback;
};
 
static SQLiteIniter& GetIniter()
{
   static SQLiteIniter sIniter;
   return sIniter;
}
} // namespace
 
Error Initialize() noexcept
{
   return GetIniter().GetError();
}
 
void SetLogCallback(LogCallback callback)
{
   GetIniter().SetLogCallback(std::move(callback));
}
 
} // namespace audacity::sqlite