LogArchiveSnapshot.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WCF / Log / System / IO / Log / LogArchiveSnapshot.cs / 1305376 / LogArchiveSnapshot.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------
namespace System.IO.Log
{ 
    using System;
    using System.Collections.Generic; 
    using System.Runtime.InteropServices; 
    using System.Text;
 
    public sealed class LogArchiveSnapshot
    {
        SequenceNumber archiveTail;
        SequenceNumber baseSequenceNumber; 
        SequenceNumber lastSequenceNumber;
 
        IEnumerable regions; 

        const int MaxFileNameLength = 260; 

        internal LogArchiveSnapshot(LogStore store,
                                    ulong lsnLow,
                                    ulong lsnHigh) 
        {
            StringBuilder baseLogFileName = new StringBuilder(MaxFileNameLength); 
            int actualLength; 
            ulong baseLogFileOffset;
            ulong baseLogFileLength; 
            ulong lsnBase;
            ulong lsnLast;
            ulong lsnArchiveTail;
 
            SafeArchiveContext archiveContext = null;
            try 
            { 
                while (!UnsafeNativeMethods.PrepareLogArchive(
                        store.Handle, 
                        baseLogFileName,
                        baseLogFileName.Capacity,
                        ref lsnLow,
                        ref lsnHigh, 
                        out actualLength,
                        out baseLogFileOffset, 
                        out baseLogFileLength, 
                        out lsnBase,
                        out lsnLast, 
                        out lsnArchiveTail,
                        out archiveContext))
                {
                    baseLogFileName.EnsureCapacity(actualLength+1); 
                }
 
                this.archiveTail = new SequenceNumber(lsnArchiveTail); 
                this.baseSequenceNumber = new SequenceNumber(lsnBase);
                this.lastSequenceNumber = new SequenceNumber(lsnLast); 

                List regions = new List();

                byte[] readBuffer = new byte[checked((uint)baseLogFileLength)]; 
                uint actualDataLength = 0;
                unsafe 
                { 
                    fixed(byte *pbReadBuffer = readBuffer)
                    { 
                        UnsafeNativeMethods.ReadLogArchiveMetadata(
                            archiveContext,
                            0,
                            readBuffer.Length, 
                            pbReadBuffer,
                            out actualDataLength); 
                    } 
                }
 
                byte[] baseFileData;
                if (actualDataLength == (uint)baseLogFileLength)
                {
                    baseFileData = readBuffer; 
                }
                else 
                { 
                    baseFileData = new byte[actualDataLength];
                    Array.Copy(readBuffer, baseFileData, baseFileData.Length); 
                }
                regions.Add(new FileRegion((long)baseLogFileLength,
                                           baseLogFileName.ToString(),
                                           (long)baseLogFileOffset, 
                                           baseFileData));
 
 
                CLFS_ARCHIVE_DESCRIPTOR descriptor = new CLFS_ARCHIVE_DESCRIPTOR();
                while(true) 
                {
                    int returnedCount;
                    if (!UnsafeNativeMethods.GetNextLogArchiveExtentSingle(
                            archiveContext, 
                            ref descriptor,
                            out returnedCount)) 
                    { 
                        break;
                    } 

                    if (returnedCount < 1) break;

                    long start = checked((long)descriptor.coffLow); 
                    long length = checked((long)(descriptor.coffHigh - descriptor.coffLow));
                    string fileName = descriptor.infoContainer.GetActualFileName(store.Handle); 
 
                    FileInfo containerInfo;
                    containerInfo = new FileInfo(fileName); 

                    regions.Add(new FileRegion(containerInfo.Length,
                                               fileName,
                                               start, 
                                               length));
                } 
 
                this.regions = regions.AsReadOnly();
            } 
            finally
            {
                if (archiveContext != null && !archiveContext.IsInvalid)
                { 
                    archiveContext.Close();
                } 
            } 
        }
 
        public IEnumerable ArchiveRegions
        {
            get
            { 
                return this.regions;
            } 
        } 

        public SequenceNumber ArchiveTail 
        {
            get
            {
                return this.archiveTail; 
            }
        } 
 
        public SequenceNumber BaseSequenceNumber
        { 
            get
            {
                return this.baseSequenceNumber;
            } 
        }
 
        public SequenceNumber LastSequenceNumber 
        {
            get 
            {
                return this.lastSequenceNumber;
            }
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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