C# IsolatedStorageFile.Demand方法代码示例

//.........这里部分代码省略.........
    
                    case FileMode.Create:           // Check for New file & Unreserve
                    case FileMode.OpenOrCreate:     // Check for new file
                    case FileMode.Truncate:         // Unreserve old file size
                    case FileMode.Append:           // Check for new file
    
                        m_isf.Lock(ref fLock);      // oldFileSize needs to be 
                                                // protected

                        try {
#if FEATURE_ISOSTORE_LIGHT
                            oldFileSize = IsolatedStorageFile.RoundToBlockSize((ulong)(FileInfo.UnsafeCreateFileInfo(m_FullPath).Length));
#else
                            oldFileSize = IsolatedStorageFile.RoundToBlockSize((ulong)LongPathFile.GetLength(m_FullPath));
#endif
                        } catch (FileNotFoundException) {
                            fNewFile = true;
                        } catch {
    
                        }
    
                        break;
    
                    case FileMode.Open:             // Open existing, else exception
                        break;
    
                }
    
                if (fNewFile)
                    m_isf.ReserveOneBlock();

#endif // FEATURE_ISOLATED_STORAGE_QUOTA_ENFORCEMENT
    
                try {

#if FEATURE_CORECLR
                    // Since FileStream's .ctor won't do a demand, we need to do our access check here.
                    m_isf.Demand(m_FullPath);
#endif

#if FEATURE_ISOSTORE_LIGHT
                    m_fs = new
                        FileStream(m_FullPath, mode, access, share, bufferSize, 
                            FileOptions.None, m_GivenPath, true);

                } catch (Exception e) {

#else
                        m_fs = new
                        FileStream(m_FullPath, mode, access, share, bufferSize,
                            FileOptions.None, m_GivenPath, true, true);

                } catch {

#endif
#if FEATURE_ISOLATED_STORAGE_QUOTA_ENFORCEMENT

                    if (fNewFile)
                        m_isf.UnreserveOneBlock();
#endif // FEATURE_ISOLATED_STORAGE_QUOTA_ENFORCEMENT
#if FEATURE_ISOSTORE_LIGHT
                    // IsoStore generally does not let arbitrary exceptions flow out: a
                    // IsolatedStorageException is thrown instead (see examples in IsolatedStorageFile.cs
                    // Keeping this scoped to coreclr just because changing the exception type thrown is a
                    // breaking change and that should not be introduced into the desktop without deliberation.
                    //
                    // Note that GetIsolatedStorageException may set InnerException. To the real exception
                    // Today it always does this, for debug and chk builds, and for other builds asks the host 
                    // if it is okay to do so.
                    throw IsolatedStorageFile.GetIsolatedStorageException("IsolatedStorage_Operation_ISFS", e);
#else
                    throw;
#endif // FEATURE_ISOSTORE_LIGHT
                }

#if FEATURE_ISOLATED_STORAGE_QUOTA_ENFORCEMENT    
                // make adjustment to the Reserve / Unreserve state
    
                if ((fNewFile == false) &&
                    ((mode == FileMode.Truncate) || (mode == FileMode.Create)))
                {
                    newFileSize = IsolatedStorageFile.RoundToBlockSize((ulong)m_fs.Length);
        
                    if (oldFileSize > newFileSize)
                        m_isf.Unreserve(oldFileSize - newFileSize);
                    else if (newFileSize > oldFileSize)     // Can this happen ?
                        m_isf.Reserve(newFileSize - oldFileSize);
                }

            } finally {
                if (fLock)
                    m_isf.Unlock();
            }
#endif // FEATURE_ISOLATED_STORAGE_QUOTA_ENFORCEMENT

#if !FEATURE_CORECLR
            CodeAccessPermission.RevertAll();
#endif
            
        }

        [System.Security.SecurityCritical] // auto-generated
        #endif
        private static String[] GetFileDirectoryNames(String path, String msg, bool file, IsolatedStorageFile isf) {
            int hr;

            if(path == null) throw new ArgumentNullException("path", Environment.GetResourceString("ArgumentNull_Path"));
            Contract.EndContractBlock();

            bool fEndsWithDirectory = false;
            char lastChar = path[path.Length - 1];
            if(lastChar == Path.DirectorySeparatorChar ||
                lastChar == Path.AltDirectorySeparatorChar ||
                lastChar == '.')
                fEndsWithDirectory = true;


            // Get an absolute path and do a security check
            String fullPath = Path.GetFullPathInternal(path);

            // GetFullPath() removes '\', "\." etc from path, we will restore 
            // it here. If path ends in a trailing slash (\), append a * 
            // or we'll  get a "Cannot find the file specified" exception
            if((fEndsWithDirectory) &&
                (fullPath[fullPath.Length - 1] != lastChar))
                fullPath += "\\*";

            // Check for read permission to the directory, not to the contents.
            String dir = Path.GetDirectoryName(fullPath);

            if(dir != null)
                dir += "\\";

            if(isf != null) {
                try {
                    isf.Demand(dir == null ? fullPath : dir);
                } catch (Exception e) {
                    throw GetIsolatedStorageException("IsolatedStorage_Operation", e);
                }
            }

            if(CompatibilitySwitches.IsAppEarlierThanWindowsPhoneMango)
            {
                // Pre Mango Windows Phone had very odd behavior for this function.  It would take the parent directory of the search pattern and do a *
                // in there.  That means something like GetDirectories("Dir1") would be treated as GetDirectories("*") and GetDirectories("Dir2\Dir3") would be
                // treated as GetDirectories("Dir2\*").

                // This also means that GetDirectories("") returned "IsolatedStorage" since it was looking at the directory above the root of Isolated Storage.
                fullPath = Path.Combine(Path.GetDirectoryName(fullPath), "*");                
            }

            String[] list = new String[10];
            int listSize = 0;
            Win32Native.WIN32_FIND_DATA data = new Win32Native.WIN32_FIND_DATA();

            // Open a Find handle 
            SafeFindHandle hnd = Win32Native.FindFirstFile(fullPath, data);
            if(hnd.IsInvalid) {
                // Calls to GetLastWin32Error overwrites HResult.  Store HResult.
                hr = Marshal.GetLastWin32Error();
                if(hr == Win32Native.ERROR_FILE_NOT_FOUND)
                    return new String[0];

                // Mango would throw DirectoryNotFoundException if we got ERROR_PATH_NOT_FOUND instead of IsolatedStorageException
                if(CompatibilitySwitches.IsAppEarlierThanWindowsPhone8 && hr == Win32Native.ERROR_PATH_NOT_FOUND)
                    __Error.WinIOError(hr, msg);

#if FEATURE_ISOSTORE_LIGHT
                throw GetIsolatedStorageException("IsolatedStorage_Operation", Marshal.GetExceptionForHR(Marshal.GetHRForLastWin32Error(), new IntPtr(-1)));
#else
                __Error.WinIOError(hr, msg);
#endif
            }

            // Keep asking for more matching files, adding file names to list
            int numEntries = 0;  // Number of directory entities we see.
            do {
                bool includeThis;  // Should this file/directory be included in the output?
                if(file)
                    includeThis = (0 == (data.dwFileAttributes & Win32Native.FILE_ATTRIBUTE_DIRECTORY));
                else {
                    includeThis = (0 != (data.dwFileAttributes & Win32Native.FILE_ATTRIBUTE_DIRECTORY));
                    // Don't add "." nor ".."
                    if(includeThis && (data.cFileName.Equals(".") || data.cFileName.Equals("..")))
                        includeThis = false;
                }

                if(includeThis) {
                    numEntries++;
                    if(listSize == list.Length) {
                        String[] newList = new String[list.Length * 2];
                        Array.Copy(list, 0, newList, 0, listSize);
                        list = newList;
                    }
                    list[listSize++] = data.cFileName;
                }

            } while(Win32Native.FindNextFile(hnd, data));

            // Make sure we quit with a sensible error.
            hr = Marshal.GetLastWin32Error();
//.........这里部分代码省略.........