CanonicalFontFamilyReference.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / MS / Internal / FontCache / CanonicalFontFamilyReference.cs / 1305600 / CanonicalFontFamilyReference.cs
                        

                        
                            //------------------------------------------------------------------------ 
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  Description: The CanonicalFontFamilyReference class is the internal representation of a font 
//               family reference. "Canonical" in this case means it has a normalized form and
//               the location part (if any) has been resolved to an absolute URI. 
// 
//               See spec at http://team/sites/Avalon/Specs/Font%20Family%20References.doc
// 
//  History:
//      1-30-2006 : niklasb - Created
//
//----------------------------------------------------------------------- 

using System; 
using MS.Internal; 
using System.Security;
 
namespace MS.Internal.FontCache
{
    internal sealed class CanonicalFontFamilyReference
    { 
        /// 
        /// Create a CanonicalFontFamilyReference given a base URI and string. 
        ///  
        /// Base URI used to resolve the location part, if it is relative.
        /// Font family reference string, in the normalized form returned 
        /// by Util.GetNormalizedFontFamilyReference.
        /// Returns a new CanonicalFontFamilyReference or CanonicalFontFamilyReference.Unresolved.
        /// 
        /// Critical - Calls critical CanonicalFontFamilyReference ctor. 
        ///          - Makes an implicit security decision (clients may demand on a Uri based on LocationUri and EscapedFileName).
        /// Safe     - Uses critical Util.IsReferenceToWindowsFonts to skip critical ctor call for unsafe inputs 
        ///  
        [SecurityCritical, SecurityTreatAsSafe]
        public static CanonicalFontFamilyReference Create(Uri baseUri, string normalizedString) 
        {
            string locationString;
            string escapedFamilyName;
 
            if (SplitFontFamilyReference(normalizedString, out locationString, out escapedFamilyName))
            { 
                Uri absoluteUri = null; 
                string fileName = null;
                bool resolved = false; 

                if (locationString == null || Util.IsReferenceToWindowsFonts(locationString))
                {
                    // No location (e.g., "#Arial") or file-name-only location (e.g., "arial.ttf#Arial") 
                    fileName = locationString;
                    resolved = true; 
                } 
                else
                { 
                    if (Uri.TryCreate(locationString, UriKind.Absolute, out absoluteUri))
                    {
                        // Location is an absolute URI. Make sure it's a supported scheme.
                        resolved = Util.IsSupportedSchemeForAbsoluteFontFamilyUri(absoluteUri); 
                    }
                    else if (baseUri != null && Util.IsEnumerableFontUriScheme(baseUri)) 
                    { 
                        // Location is relative to the base URI.
                        resolved = Uri.TryCreate(baseUri, locationString, out absoluteUri); 
                    }
                }

                if (resolved) 
                {
                    string unescapeFamilyName = Uri.UnescapeDataString(escapedFamilyName); 
                    if (fileName != null) 
                    {
                        return new CanonicalFontFamilyReference(fileName, unescapeFamilyName); 
                    }
                    else
                    {
                        return new CanonicalFontFamilyReference(absoluteUri, unescapeFamilyName); 
                    }
                } 
            } 

            return _unresolved; 
        }

        /// 
        /// Represents a font family reference that could not be resolved, e.g., because of an 
        /// invalid location or unsupported scheme.
        ///  
        public static CanonicalFontFamilyReference Unresolved 
        {
            get { return _unresolved; } 
        }

        /// 
        /// Font family name. This string is not URI encoded (escaped). 
        /// 
        public string FamilyName 
        { 
            get { return _familyName; }
        } 

        /// 
        /// If a font family reference's location part comprises a file name only (e.g., "arial.ttf#Arial")
        /// this property is the URI-encoded file name. In this case, the implied location of the file is 
        /// the default Windows Fonts folder and the LocationUri property is null. In all other cases,
        /// this property is null. 
        ///  
        public string EscapedFileName
        { 
            get;

            /// 
            /// Critical - Sets critical member that can be used to control the path fonts are loaded from. 
            /// 
            [SecurityCritical] 
            private set; 
        }
 
        /// 
        /// Gets the font location if a specific location is given; otherwise returns null indicating
        /// the default Windows Fonts folder.
        ///  
        public Uri LocationUri
        { 
            get { return _absoluteLocationUri; } 
        }
 
        public bool Equals(CanonicalFontFamilyReference other)
        {
            return other != null &&
                other._absoluteLocationUri == _absoluteLocationUri && 
                other.EscapedFileName == EscapedFileName &&
                other._familyName == _familyName; 
        } 

        public override bool Equals(object obj) 
        {
            return Equals(obj as CanonicalFontFamilyReference);
        }
 
        public override int GetHashCode()
        { 
            if (_absoluteLocationUri == null && EscapedFileName == null) 
            {
                // Typical case where no location is specified 
                return _familyName.GetHashCode();
            }
            else
            { 
                // Either we have a URI or a file name, never both
                int hash = (_absoluteLocationUri != null) ? 
                    _absoluteLocationUri.GetHashCode() : 
                    EscapedFileName.GetHashCode();
 
                // Combine the location hash with the family name hash
                hash = HashFn.HashMultiply(hash) + _familyName.GetHashCode();
                return HashFn.HashScramble(hash);
            } 
        }
 
        ///  
        /// Critical - Sets critical member that can be used to control the path fonts are loaded from.
        ///  
        [SecurityCritical]
        private CanonicalFontFamilyReference(string escapedFileName, string familyName)
        {
            EscapedFileName = escapedFileName; 
            _familyName = familyName;
        } 
 
        private CanonicalFontFamilyReference(Uri absoluteLocationUri, string familyName)
        { 
            _absoluteLocationUri = absoluteLocationUri;
            _familyName = familyName;
        }
 
        private static bool SplitFontFamilyReference(string normalizedString, out string locationString, out string escapedFamilyName)
        { 
            int familyNameIndex; 

            if (normalizedString[0] == '#') 
            {
                locationString = null;
                familyNameIndex = 1;
            } 
            else
            { 
                int i = normalizedString.IndexOf('#'); 
                locationString = normalizedString.Substring(0, i);
                familyNameIndex = i + 1; 
            }

            if (familyNameIndex < normalizedString.Length)
            { 
                escapedFamilyName = normalizedString.Substring(familyNameIndex);
                return true; 
            } 
            else
            { 
                escapedFamilyName = null;
                return false;
            }
        } 

        private Uri     _absoluteLocationUri; 
        private string  _familyName; 
        private static readonly CanonicalFontFamilyReference _unresolved = new CanonicalFontFamilyReference((Uri)null, string.Empty);
    } 
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------ 
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  Description: The CanonicalFontFamilyReference class is the internal representation of a font 
//               family reference. "Canonical" in this case means it has a normalized form and
//               the location part (if any) has been resolved to an absolute URI. 
// 
//               See spec at http://team/sites/Avalon/Specs/Font%20Family%20References.doc
// 
//  History:
//      1-30-2006 : niklasb - Created
//
//----------------------------------------------------------------------- 

using System; 
using MS.Internal; 
using System.Security;
 
namespace MS.Internal.FontCache
{
    internal sealed class CanonicalFontFamilyReference
    { 
        /// 
        /// Create a CanonicalFontFamilyReference given a base URI and string. 
        ///  
        /// Base URI used to resolve the location part, if it is relative.
        /// Font family reference string, in the normalized form returned 
        /// by Util.GetNormalizedFontFamilyReference.
        /// Returns a new CanonicalFontFamilyReference or CanonicalFontFamilyReference.Unresolved.
        /// 
        /// Critical - Calls critical CanonicalFontFamilyReference ctor. 
        ///          - Makes an implicit security decision (clients may demand on a Uri based on LocationUri and EscapedFileName).
        /// Safe     - Uses critical Util.IsReferenceToWindowsFonts to skip critical ctor call for unsafe inputs 
        ///  
        [SecurityCritical, SecurityTreatAsSafe]
        public static CanonicalFontFamilyReference Create(Uri baseUri, string normalizedString) 
        {
            string locationString;
            string escapedFamilyName;
 
            if (SplitFontFamilyReference(normalizedString, out locationString, out escapedFamilyName))
            { 
                Uri absoluteUri = null; 
                string fileName = null;
                bool resolved = false; 

                if (locationString == null || Util.IsReferenceToWindowsFonts(locationString))
                {
                    // No location (e.g., "#Arial") or file-name-only location (e.g., "arial.ttf#Arial") 
                    fileName = locationString;
                    resolved = true; 
                } 
                else
                { 
                    if (Uri.TryCreate(locationString, UriKind.Absolute, out absoluteUri))
                    {
                        // Location is an absolute URI. Make sure it's a supported scheme.
                        resolved = Util.IsSupportedSchemeForAbsoluteFontFamilyUri(absoluteUri); 
                    }
                    else if (baseUri != null && Util.IsEnumerableFontUriScheme(baseUri)) 
                    { 
                        // Location is relative to the base URI.
                        resolved = Uri.TryCreate(baseUri, locationString, out absoluteUri); 
                    }
                }

                if (resolved) 
                {
                    string unescapeFamilyName = Uri.UnescapeDataString(escapedFamilyName); 
                    if (fileName != null) 
                    {
                        return new CanonicalFontFamilyReference(fileName, unescapeFamilyName); 
                    }
                    else
                    {
                        return new CanonicalFontFamilyReference(absoluteUri, unescapeFamilyName); 
                    }
                } 
            } 

            return _unresolved; 
        }

        /// 
        /// Represents a font family reference that could not be resolved, e.g., because of an 
        /// invalid location or unsupported scheme.
        ///  
        public static CanonicalFontFamilyReference Unresolved 
        {
            get { return _unresolved; } 
        }

        /// 
        /// Font family name. This string is not URI encoded (escaped). 
        /// 
        public string FamilyName 
        { 
            get { return _familyName; }
        } 

        /// 
        /// If a font family reference's location part comprises a file name only (e.g., "arial.ttf#Arial")
        /// this property is the URI-encoded file name. In this case, the implied location of the file is 
        /// the default Windows Fonts folder and the LocationUri property is null. In all other cases,
        /// this property is null. 
        ///  
        public string EscapedFileName
        { 
            get;

            /// 
            /// Critical - Sets critical member that can be used to control the path fonts are loaded from. 
            /// 
            [SecurityCritical] 
            private set; 
        }
 
        /// 
        /// Gets the font location if a specific location is given; otherwise returns null indicating
        /// the default Windows Fonts folder.
        ///  
        public Uri LocationUri
        { 
            get { return _absoluteLocationUri; } 
        }
 
        public bool Equals(CanonicalFontFamilyReference other)
        {
            return other != null &&
                other._absoluteLocationUri == _absoluteLocationUri && 
                other.EscapedFileName == EscapedFileName &&
                other._familyName == _familyName; 
        } 

        public override bool Equals(object obj) 
        {
            return Equals(obj as CanonicalFontFamilyReference);
        }
 
        public override int GetHashCode()
        { 
            if (_absoluteLocationUri == null && EscapedFileName == null) 
            {
                // Typical case where no location is specified 
                return _familyName.GetHashCode();
            }
            else
            { 
                // Either we have a URI or a file name, never both
                int hash = (_absoluteLocationUri != null) ? 
                    _absoluteLocationUri.GetHashCode() : 
                    EscapedFileName.GetHashCode();
 
                // Combine the location hash with the family name hash
                hash = HashFn.HashMultiply(hash) + _familyName.GetHashCode();
                return HashFn.HashScramble(hash);
            } 
        }
 
        ///  
        /// Critical - Sets critical member that can be used to control the path fonts are loaded from.
        ///  
        [SecurityCritical]
        private CanonicalFontFamilyReference(string escapedFileName, string familyName)
        {
            EscapedFileName = escapedFileName; 
            _familyName = familyName;
        } 
 
        private CanonicalFontFamilyReference(Uri absoluteLocationUri, string familyName)
        { 
            _absoluteLocationUri = absoluteLocationUri;
            _familyName = familyName;
        }
 
        private static bool SplitFontFamilyReference(string normalizedString, out string locationString, out string escapedFamilyName)
        { 
            int familyNameIndex; 

            if (normalizedString[0] == '#') 
            {
                locationString = null;
                familyNameIndex = 1;
            } 
            else
            { 
                int i = normalizedString.IndexOf('#'); 
                locationString = normalizedString.Substring(0, i);
                familyNameIndex = i + 1; 
            }

            if (familyNameIndex < normalizedString.Length)
            { 
                escapedFamilyName = normalizedString.Substring(familyNameIndex);
                return true; 
            } 
            else
            { 
                escapedFamilyName = null;
                return false;
            }
        } 

        private Uri     _absoluteLocationUri; 
        private string  _familyName; 
        private static readonly CanonicalFontFamilyReference _unresolved = new CanonicalFontFamilyReference((Uri)null, string.Empty);
    } 
}


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

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