DriveInfo.cs source code in C# .NET

                        Code:
                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / IO / DriveInfo.cs / 1 / DriveInfo.cs
                        
                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Class:  DriveInfo 
**
** 
** Purpose: Exposes routines for exploring a drive.
**
**
===========================================================*/ 

using System; 
using System.Text; 
using System.Runtime.InteropServices;
using Microsoft.Win32; 
using System.Security.Permissions;
using System.Runtime.Serialization;
using System.Runtime.Versioning;
 
namespace System.IO
{ 
    // Matches Win32's DRIVE_XXX #defines from winbase.h 
    [Serializable]
[System.Runtime.InteropServices.ComVisible(true)] 
    public enum DriveType
    {
        Unknown = 0,
        NoRootDirectory = 1, 
        Removable = 2,
        Fixed = 3, 
        Network = 4, 
        CDRom = 5,
        Ram = 6 
    }

    // Ideally we'll get a better security permission, but possibly
    // not for Whidbey. 
    [Serializable]
    [ComVisible(true)] 
    public sealed class DriveInfo : ISerializable 
    {
        private String _name; 

        private const String NameField = "_name";  // For serialization

        public DriveInfo(String driveName) 
        {
            if (driveName == null) 
                throw new ArgumentNullException("driveName"); 
            if (driveName.Length == 1)
                _name = driveName + ":\\"; 
            else {
                // GetPathRoot does not check all invalid characters
                Path.CheckInvalidPathChars(driveName);
                _name = Path.GetPathRoot(driveName); 
                // Disallow null or empty drive letters and UNC paths
                if (_name == null || _name.Length == 0 || _name.StartsWith("\\\\", StringComparison.Ordinal)) 
                    throw new ArgumentException(Environment.GetResourceString("Arg_MustBeDriveLetterOrRootDir")); 
            }
            // We want to normalize to have a trailing backslash so we don't have two equivalent forms and 
            // because some Win32 API don't work without it.
            if (_name.Length == 2 && _name[1] == ':') {
                _name = _name + "\\";
            } 

            // Now verify that the drive letter could be a real drive name. 
            // On Windows this means it's between A and Z, ignoring case. 
            // On a Unix platform, perhaps this should be a device name with
            // a partition like /dev/hdc0, or possibly a mount point. 
            char letter = driveName[0];
            if (!((letter >= 'A' && letter <= 'Z') || (letter >= 'a' && letter <= 'z')))
                throw new ArgumentException(Environment.GetResourceString("Arg_MustBeDriveLetterOrRootDir"));
 
            // Now do a security check.
            String demandPath = _name + '.'; 
            new FileIOPermission(FileIOPermissionAccess.PathDiscovery, demandPath).Demand(); 
        }
 
        private DriveInfo(SerializationInfo info, StreamingContext context)
        {
            // Need to add in a security check here once it has been spec'ed.
            _name = (String) info.GetValue(NameField, typeof(String)); 

            // Now do a security check. 
            String demandPath = _name + '.'; 
            new FileIOPermission(FileIOPermissionAccess.PathDiscovery, demandPath).Demand();
        } 

        public String Name {
            get { return _name; }
        } 

        public DriveType DriveType { 
            get { 
                // GetDriveType can't fail
                return (DriveType) Win32Native.GetDriveType(Name); 
            }
        }

        public String DriveFormat { 
            [ResourceExposure(ResourceScope.None)]
            [ResourceConsumption(ResourceScope.Process, ResourceScope.Process)] 
            get { 
                const int volNameLen = 50;
                StringBuilder volumeName = new StringBuilder(volNameLen); 
                const int fileSystemNameLen = 50;
                StringBuilder fileSystemName = new StringBuilder(fileSystemNameLen);
                int serialNumber, maxFileNameLen, fileSystemFlags;
 
                int oldMode = Win32Native.SetErrorMode(Win32Native.SEM_FAILCRITICALERRORS);
                try { 
                    bool r = Win32Native.GetVolumeInformation(Name, volumeName, volNameLen, out serialNumber, out maxFileNameLen, out fileSystemFlags, fileSystemName, fileSystemNameLen); 
                    if (!r) {
                        int errorCode = Marshal.GetLastWin32Error(); 
                        // Win9x appears to return ERROR_INVALID_DATA when a
                        // drive doesn't exist.
                        if (errorCode == Win32Native.ERROR_INVALID_DATA)
                            errorCode = Win32Native.ERROR_INVALID_DRIVE; 
                        __Error.WinIODriveError(Name, errorCode);
                    } 
                } 
                finally {
                    Win32Native.SetErrorMode(oldMode); 
                }
                return fileSystemName.ToString();
            }
        } 

        public bool IsReady { 
            [ResourceExposure(ResourceScope.None)] 
            [ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)]
            get { 
                return Directory.InternalExists(Name);
            }
        }
 
        public long AvailableFreeSpace {
            [ResourceExposure(ResourceScope.None)] 
            [ResourceConsumption(ResourceScope.Process, ResourceScope.Process)] 
            get {
                long userBytes, totalBytes, freeBytes; 
                int oldMode = Win32Native.SetErrorMode(Win32Native.SEM_FAILCRITICALERRORS);
                try {
                    bool r = Win32Native.GetDiskFreeSpaceEx(Name, out userBytes, out totalBytes, out freeBytes);
                    if (!r) 
                        __Error.WinIODriveError(Name);
                } 
                finally { 
                    Win32Native.SetErrorMode(oldMode);
                } 
                return userBytes;
            }
        }
 
        public long TotalFreeSpace {
            [ResourceExposure(ResourceScope.None)] 
            [ResourceConsumption(ResourceScope.Process, ResourceScope.Process)] 
            get {
                long userBytes, totalBytes, freeBytes; 
                int oldMode = Win32Native.SetErrorMode(Win32Native.SEM_FAILCRITICALERRORS);
                try {
                    bool r = Win32Native.GetDiskFreeSpaceEx(Name, out userBytes, out totalBytes, out freeBytes);
                    if (!r) 
                        __Error.WinIODriveError(Name);
                } 
                finally { 
                    Win32Native.SetErrorMode(oldMode);
                } 
                return freeBytes;
            }
        }
 
        public long TotalSize {
            [ResourceExposure(ResourceScope.None)] 
            [ResourceConsumption(ResourceScope.Process, ResourceScope.Process)] 
            get {
                // Don't cache this, to handle variable sized floppy drives 
                // or other various removable media drives.
                long userBytes, totalBytes, freeBytes;
                int oldMode = Win32Native.SetErrorMode(Win32Native.SEM_FAILCRITICALERRORS);
                try { 
                    bool r = Win32Native.GetDiskFreeSpaceEx(Name, out userBytes, out totalBytes, out freeBytes);
                    if (!r) 
                        __Error.WinIODriveError(Name); 
                }
                finally { 
                    Win32Native.SetErrorMode(oldMode);
                }
                return totalBytes;
            } 
        }
 
        [ResourceExposure(ResourceScope.Machine)] 
        [ResourceConsumption(ResourceScope.Machine)]
        public static DriveInfo[] GetDrives() 
        {
            // Directory.GetLogicalDrives demands unmanaged code permission
            String[] drives = Directory.GetLogicalDrives();
            DriveInfo[] di = new DriveInfo[drives.Length]; 
            for(int i=0; i 
        // No need for LinkDemand of SerializationFormatter here as this is a interface private
        // methodimpl and the linkdeamand specified on ISerializable will cover this. 
        void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context) 
        {
            // No need for an additional security check - everything is public. 
            info.AddValue(NameField, _name, typeof(String));
        }
    }
}
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