Code:
/ DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / Media / Imaging / BitmapMetadataEnumerator.cs / 1 / BitmapMetadataEnumerator.cs
//------------------------------------------------------------------------------ // Microsoft Windows Client Platform // Copyright (c) Microsoft Corporation, 2005 // // File: BitmapMetadataEnumerator.cs //----------------------------------------------------------------------------- // Allow suppression of certain presharp messages #pragma warning disable 1634, 1691 using System; using System.Collections; using System.Collections.Generic; using System.Runtime.InteropServices; using System.Security; using System.Security.Permissions; using System.Diagnostics; using MS.Internal; using MS.Internal.PresentationCore; // SecurityHelper using MS.Win32.PresentationCore; using SR=MS.Internal.PresentationCore.SR; using SRID=MS.Internal.PresentationCore.SRID; namespace System.Windows.Media.Imaging { ////// An enumerator that iterates over the children of a timeline. /// internal struct BitmapMetadataEnumerator : IEnumerator, IEnumerator { #region External interface #region IEnumerator interface #region Properties /// /// Gets the current element in the collection. /// ////// The current element in the collection. /// ////// Critical - Accesses unmanaged code /// TreatAsSafe - inputs are verified or safe /// [SecurityCritical, SecurityTreatAsSafe] object IEnumerator.Current { get { return Current; } } #endregion // Properties #region Methods ////// Advances the enumerator to the next element of the collection. /// ////// True if the enumerator was successfully advanced to the next element; /// false if the enumerator has passed the end of the collection. /// ////// Critical - Accesses unmanaged code /// TreatAsSafe - inputs are verified or safe /// [SecurityCritical, SecurityTreatAsSafe] public bool MoveNext() { if (_fStarted && _current == null) { return false; } _fStarted = true; IntPtr ppStr = IntPtr.Zero; Int32 celtFetched = 0; try { int hr = UnsafeNativeMethods.EnumString.Next( _enumeratorHandle, 1, ref ppStr, ref celtFetched); if (HRESULT.IsWindowsCodecError(hr)) { _current = null; return false; } HRESULT.Check(hr); if (celtFetched == 0) { _current = null; return false; } else { _current = Marshal.PtrToStringUni(ppStr); } } finally { if (ppStr != IntPtr.Zero) { Marshal.FreeCoTaskMem(ppStr); ppStr = IntPtr.Zero; } } return true; } ////// Sets the enumerator to its initial position, which is before the first element /// in the collection. /// ////// Critical - Accesses unmanaged code /// TreatAsSafe - inputs are verified or safe /// [SecurityCritical, SecurityTreatAsSafe] public void Reset() { HRESULT.Check(UnsafeNativeMethods.EnumString.Reset(_enumeratorHandle)); _current = null; _fStarted = false; } #endregion // Methods #endregion // IEnumerator interface #region Properties ////// The current timeline referenced by this enumerator. /// public String Current { get { if (_current == null) { if (!_fStarted) { #pragma warning suppress 56503 // Suppress presharp warning: Follows a pattern similar to Nullable. throw new InvalidOperationException(SR.Get(SRID.Enumerator_NotStarted)); } else { #pragma warning suppress 56503 // Suppress presharp warning: Follows a pattern similar to Nullable. throw new InvalidOperationException(SR.Get(SRID.Enumerator_ReachedEnd)); } } return _current; } } ////// /// void IDisposable.Dispose() { // Do nothing - Required by the IEnumerable contract. } #endregion // Properties #endregion // External interface #region Internal implementation #region Construction ////// Creates an enumerator iterates over the children of the specified container. /// /// /// Handle to a metadata query reader/writer /// ////// Critical - Accesses unmanaged code /// TreatAsSafe - inputs are verified or safe /// [SecurityCritical, SecurityTreatAsSafe] internal BitmapMetadataEnumerator(SafeMILHandle metadataHandle) { Debug.Assert(metadataHandle != null && !metadataHandle.IsInvalid); HRESULT.Check(UnsafeNativeMethods.WICMetadataQueryReader.GetEnumerator( metadataHandle, out _enumeratorHandle)); _current = null; _fStarted = false; } #endregion // Construction #region Methods #endregion // Methods #region Data ////// Critical - pointer to an unmanaged object that methods are called on. /// [SecurityCritical] private SafeMILHandle _enumeratorHandle; private String _current; private bool _fStarted; #endregion // Data #endregion // Internal implementation } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
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