/// <summary>
/// Opens an installer package for use with functions that access the product database and install engine,
/// returning an Session object.
/// </summary>
/// <param name="packagePath">Path to the package</param>
/// <param name="ignoreMachineState">Specifies whether or not the create a Session object that ignores the
/// computer state and that is incapable of changing the current computer state. A value of false yields
/// the normal behavior. A value of true creates a "safe" Session object that cannot change of the current
/// machine state.</param>
/// <returns>A Session object allowing access to the product database and install engine</returns>
/// <exception cref="InstallerException">The product could not be opened</exception>
/// <exception cref="InstallerException">The installer configuration data is corrupt</exception>
/// <remarks><p>
/// Note that only one Session object can be opened by a single process. OpenPackage cannot be used in a
/// custom action because the active installation is the only session allowed.
/// </p><p>
/// A "safe" Session object ignores the current computer state when opening the package and prevents
/// changes to the current computer state.
/// </p><p>
/// The Session object should be <see cref="InstallerHandle.Close"/>d after use.
/// It is best that the handle be closed manually as soon as it is no longer
/// needed, as leaving lots of unused handles open can degrade performance.
/// </p><p>
/// Win32 MSI APIs:
/// <a href="http://msdn.microsoft.com/library/en-us/msi/setup/msiopenpackage.asp">MsiOpenPackage</a>,
/// <a href="http://msdn.microsoft.com/library/en-us/msi/setup/msiopenpackageex.asp">MsiOpenPackageEx</a>
/// </p></remarks>
public static Session OpenPackage(string packagePath, bool ignoreMachineState)
{
int sessionHandle;
uint ret = NativeMethods.MsiOpenPackageEx(packagePath, ignoreMachineState ? (uint)1 : 0, out sessionHandle);
if (ret != 0)
{
throw InstallerException.ExceptionFromReturnCode(ret);
}
return(new Session((IntPtr)sessionHandle, true));
}
