Merge pull request #82 from JohannStudanskiEnscape/ValuePreprocessor

Integrate a way to set up custom value preprocessors

plist-cil.test/ValuePreprocessorTests.cs

@@ -0,0 +1,125 @@
+using System;
+using System.Linq;
+using Claunia.PropertyList;
+using Xunit;
+
+namespace plistcil.test
+{
+    public static class ValuePreprocessorTests
+    {
+        // lock tests to make sure temporarily added / replaced preprocessors don't interfere with the other tests in this suite
+        private static readonly object _testLock = new();
+
+        [Fact]
+        public static void TestPassiveDefaultPreprocessorsRegistered()
+        {
+            byte[] testByteArray = [0x1, 0x2, 0x4, 0x8];
+
+            Assert.Equal(true, ValuePreprocessor.Preprocess(true, ValuePreprocessor.Type.BOOL));
+            Assert.Equal(false, ValuePreprocessor.Preprocess(false, ValuePreprocessor.Type.BOOL));
+            Assert.Equal("true", ValuePreprocessor.Preprocess("true", ValuePreprocessor.Type.BOOL));
+
+            Assert.Equal("42", ValuePreprocessor.Preprocess("42", ValuePreprocessor.Type.INTEGER));
+            Assert.Equal(testByteArray, ValuePreprocessor.Preprocess(testByteArray, ValuePreprocessor.Type.INTEGER));
+
+            Assert.Equal("3.14159", ValuePreprocessor.Preprocess("3.14159", ValuePreprocessor.Type.FLOATING_POINT));
+            Assert.Equal(testByteArray, ValuePreprocessor.Preprocess(testByteArray, ValuePreprocessor.Type.FLOATING_POINT));
+
+            Assert.Equal("2.71828", ValuePreprocessor.Preprocess("2.71828", ValuePreprocessor.Type.UNDEFINED_NUMBER));
+
+            Assert.Equal("TestString", ValuePreprocessor.Preprocess("TestString", ValuePreprocessor.Type.STRING));
+            Assert.Equal(testByteArray, ValuePreprocessor.Preprocess(testByteArray, ValuePreprocessor.Type.STRING));
+
+            Assert.Equal("TestData", ValuePreprocessor.Preprocess("TestData", ValuePreprocessor.Type.DATA));
+            Assert.Equal(testByteArray, ValuePreprocessor.Preprocess(testByteArray, ValuePreprocessor.Type.DATA));
+
+            Assert.Equal(testByteArray, ValuePreprocessor.Preprocess(testByteArray, ValuePreprocessor.Type.DATE));
+            Assert.Equal("01.02.1903", ValuePreprocessor.Preprocess("01.02.1903", ValuePreprocessor.Type.DATE));
+            Assert.Equal(23.0, ValuePreprocessor.Preprocess(23.0, ValuePreprocessor.Type.DATE));
+        }
+
+        [Fact]
+        public static void TestRegisterPreprocessor()
+        {
+            lock(_testLock)
+            {
+                Func<string, string> examplePreprocessor = value => new string(value.Reverse().ToArray());
+                string               testString          = "TestString";
+                string               expected            = "gnirtStseT";
+
+                var testType = (ValuePreprocessor.Type)42;
+
+                ValuePreprocessor.Set(examplePreprocessor, testType);
+                string actual = ValuePreprocessor.Preprocess(testString, testType);
+
+                Assert.Equal(actual, expected);
+
+                ValuePreprocessor.Unset<string>(testType);
+            }
+        }
+
+        [Fact]
+        public static void TestRegisteredPreprocessorSelection1()
+        {
+            lock(_testLock)
+            {
+                Func<short, short> examplePreprocessor = value => (short)(value - 1);
+                short              testShort           = 42;
+                string             testString          = "TestString";
+
+                var testType = (ValuePreprocessor.Type)42;
+
+                // correct value type, differing data type
+                ValuePreprocessor.Set(examplePreprocessor, testType);
+                ValuePreprocessor.Set(ValuePreprocessor.GetDefault<string>(), testType);
+
+                string actual1 = ValuePreprocessor.Preprocess(testString, testType);
+                short  actual2 = ValuePreprocessor.Preprocess(testShort, testType);
+
+                // assert unchanged, since the selected preprocessor != tested preprocessor
+                Assert.Equal(actual1, testString);
+                Assert.NotEqual(actual2, testShort);
+
+                ValuePreprocessor.Remove<short>(testType);
+                ValuePreprocessor.Remove<string>(testType);
+            }
+        }
+
+        [Fact]
+        public static void TestRegisteredPreprocessorSelection2()
+        {
+            lock(_testLock)
+            {
+                Func<string, string> examplePreprocessor = value => new string(value.Reverse().ToArray());
+                byte[]               testByteArray       = [0x42,];
+                string               testString          = "TestString";
+
+                var testType = (ValuePreprocessor.Type)42;
+
+                // correct value type, differing data type
+                ValuePreprocessor.Set(examplePreprocessor, testType);
+                ValuePreprocessor.Set(ValuePreprocessor.GetDefault<byte[]>(), testType);
+
+                string actual1 = ValuePreprocessor.Preprocess(testString, testType);
+                byte[] actual2 = ValuePreprocessor.Preprocess(testByteArray, testType);
+
+                Assert.NotEqual(actual1, testString);
+
+                // assert unchanged, since the selected preprocessor != tested preprocessor
+                Assert.Equal(actual2, testByteArray);
+
+                ValuePreprocessor.Unset<string>(testType);
+                ValuePreprocessor.Remove<byte[]>(testType);
+            }
+        }
+
+        [Fact]
+        public static void TestUnregisteredPreprocessorThrows()
+        {
+            int[] testArray = [1, 2, 4, 8];
+
+            // there's no registered preprocessor for byte array arguments for STRING
+            Assert.Throws<ArgumentException>(() => ValuePreprocessor.Preprocess(testArray, ValuePreprocessor.Type.STRING));
+        }
+    }
+}

plist-cil/ASCIIPropertyListParser.cs

@@ -409,15 +409,15 @@ namespace Claunia.PropertyList
                        quotedString[4]     == DATE_DATE_FIELD_DELIMITER)
                         try
                         {
-                            return new NSDate(quotedString);
+                            return new NSDate(ValuePreprocessor.Preprocess(quotedString, ValuePreprocessor.Type.DATE));
                         }
                         catch(Exception)
                         {
                             //not a date? --> return string
-                            return new NSString(quotedString);
+                            return new NSString(ValuePreprocessor.Preprocess(quotedString, ValuePreprocessor.Type.STRING));
                         }
 
-                    return new NSString(quotedString);
+                    return new NSString(ValuePreprocessor.Preprocess(quotedString, ValuePreprocessor.Type.STRING));
                 }
                 default:
                 {
@@ -429,7 +429,7 @@ namespace Claunia.PropertyList
                     //non-numerical -> string or boolean
                     string parsedString = ParseString();
 
-                    return new NSString(parsedString);
+                    return new NSString(ValuePreprocessor.Preprocess(parsedString, ValuePreprocessor.Type.STRING));
                 }
             }
         }
@@ -529,9 +529,9 @@ namespace Claunia.PropertyList
                     Expect(DATA_GSBOOL_TRUE_TOKEN, DATA_GSBOOL_FALSE_TOKEN);
 
                     if(Accept(DATA_GSBOOL_TRUE_TOKEN))
-                        obj = new NSNumber(true);
+                        obj = new NSNumber(ValuePreprocessor.Preprocess(true, ValuePreprocessor.Type.BOOL));
                     else
-                        obj = new NSNumber(false);
+                        obj = new NSNumber(ValuePreprocessor.Preprocess(false, ValuePreprocessor.Type.BOOL));
 
                     //Skip the parsed boolean token
                     Skip();
@@ -541,14 +541,14 @@ namespace Claunia.PropertyList
                     //Date
                     Skip();
                     string dateString = ReadInputUntil(DATA_END_TOKEN);
-                    obj = new NSDate(dateString);
+                    obj = new NSDate(ValuePreprocessor.Preprocess(dateString, ValuePreprocessor.Type.DATE));
                 }
                 else if(Accept(DATA_GSINT_BEGIN_TOKEN, DATA_GSREAL_BEGIN_TOKEN))
                 {
                     //Number
                     Skip();
                     string numberString = ReadInputUntil(DATA_END_TOKEN);
-                    obj = new NSNumber(numberString);
+                    obj = new NSNumber(ValuePreprocessor.Preprocess(numberString, ValuePreprocessor.Type.UNDEFINED_NUMBER));
                 }
 
                 //parse data end token
@@ -569,7 +569,7 @@ namespace Claunia.PropertyList
                     bytes[i] = (byte)byteValue;
                 }
 
-                obj = new NSData(bytes);
+                obj = new NSData(ValuePreprocessor.Preprocess(bytes, ValuePreprocessor.Type.DATA));
 
                 //skip end token
                 Skip();
@@ -586,18 +586,18 @@ namespace Claunia.PropertyList
 
             if(numericalString.Length <= 4 ||
                numericalString[4]     != DATE_DATE_FIELD_DELIMITER)
-                return new NSString(numericalString);
+                return new NSString(ValuePreprocessor.Preprocess(numericalString, ValuePreprocessor.Type.STRING));
 
             try
             {
-                return new NSDate(numericalString);
+                return new NSDate(ValuePreprocessor.Preprocess(numericalString, ValuePreprocessor.Type.DATE));
             }
             catch(Exception)
             {
                 //An exception occurs if the string is not a date but just a string
             }
 
-            return new NSString(numericalString);
+            return new NSString(ValuePreprocessor.Preprocess(numericalString, ValuePreprocessor.Type.STRING));
         }
 
         /// <summary>

plist-cil/BinaryPropertyListParser.cs

@@ -158,7 +158,7 @@ namespace Claunia.PropertyList
             //Read all bytes into a list
             byte[] buf = PropertyListParser.ReadAll(fs);
 
-            // Don't close the stream - that would be the responisibility of code that class
+            // Don't close the stream - that would be the responsibility of code that class
             // Parse
             return Parse(buf);
         }
@@ -204,12 +204,12 @@ namespace Claunia.PropertyList
                         case 0x8:
                         {
                             //false
-                            return new NSNumber(false);
+                            return new NSNumber(ValuePreprocessor.Preprocess(false, ValuePreprocessor.Type.BOOL));
                         }
                         case 0x9:
                         {
                             //true
-                            return new NSNumber(true);
+                            return new NSNumber(ValuePreprocessor.Preprocess(true, ValuePreprocessor.Type.BOOL));
                         }
                         case 0xC:
                         {
@@ -243,14 +243,14 @@ namespace Claunia.PropertyList
                     //integer
                     int length = 1 << objInfo;
 
-                    return new NSNumber(bytes.Slice(offset + 1, length), NSNumber.INTEGER);
+                    return new NSNumber(ValuePreprocessor.Preprocess(bytes.Slice(offset + 1, length).ToArray(), ValuePreprocessor.Type.INTEGER), NSNumber.INTEGER);
                 }
                 case 0x2:
                 {
                     //real
                     int length = 1 << objInfo;
 
-                    return new NSNumber(bytes.Slice(offset + 1, length), NSNumber.REAL);
+                    return new NSNumber(ValuePreprocessor.Preprocess(bytes.Slice(offset + 1, length).ToArray(), ValuePreprocessor.Type.FLOATING_POINT), NSNumber.REAL);
                 }
                 case 0x3:
                 {
@@ -260,21 +260,21 @@ namespace Claunia.PropertyList
                             PropertyListFormatException("The given binary property list contains a date object of an unknown type (" +
                                                         objInfo + ")");
 
-                    return new NSDate(bytes.Slice(offset + 1, 8));
+                    return new NSDate(ValuePreprocessor.Preprocess(bytes.Slice(offset + 1, 8).ToArray(), ValuePreprocessor.Type.DATE));
                 }
                 case 0x4:
                 {
                     //Data
                     ReadLengthAndOffset(bytes, objInfo, offset, out int length, out int dataoffset);
 
-                    return new NSData(CopyOfRange(bytes, offset + dataoffset, offset + dataoffset + length));
+                    return new NSData(ValuePreprocessor.Preprocess(CopyOfRange(bytes, offset + dataoffset, offset + dataoffset + length), ValuePreprocessor.Type.DATA));
                 }
                 case 0x5:
                 {
                     //ASCII String, each character is 1 byte
                     ReadLengthAndOffset(bytes, objInfo, offset, out int length, out int stroffset);
 
-                    return new NSString(bytes.Slice(offset + stroffset, length), Encoding.ASCII);
+                    return new NSString(ValuePreprocessor.Preprocess(bytes.Slice(offset + stroffset, length).ToArray(), ValuePreprocessor.Type.STRING), Encoding.ASCII);
                 }
                 case 0x6:
                 {

plist-cil/PropertyListParser.cs

@@ -1,4 +1,4 @@
-// plist-cil - An open source library to parse and generate property lists for .NET
+// plist-cil - An open source library to parse and generate property lists for .NET
 // Copyright (C) 2015 Natalia Portillo
 //
 // This code is based on:
@@ -147,6 +147,12 @@ namespace Claunia.PropertyList
             return type;
         }
 
+        /// <summary>Set up preprocessing functions for plist values.</summary>
+        /// <param name="preprocessor">A function that preprocesses the passed string and returns the adjusted value.</param>
+        /// <param name="type">The type of value preprocessor to use.</param>
+        public static void SetValuePreprocessor<T>(Func<T, T> preprocessor, ValuePreprocessor.Type type) =>
+            ValuePreprocessor.Set(preprocessor, type);
+
         /// <summary>Reads all bytes from an Stream and stores them in an array, up to a maximum count.</summary>
         /// <param name="fs">The Stream pointing to the data that should be stored in the array.</param>
         internal static byte[] ReadAll(Stream fs)

plist-cil/ValuePreprocessor.cs

@@ -0,0 +1,121 @@
+using System;
+using System.Collections.Generic;
+
+namespace Claunia.PropertyList
+{
+    /// <summary>
+    ///     Allows you to override the default value class initialization for the values found
+    ///     in the parsed plists by registering your own preprocessing implementations.
+    /// </summary>
+    public static class ValuePreprocessor
+    {
+        /// <summary>
+        ///     Indicates the semantic type of content the preprocessor will work on--independent
+        ///     from the underlying data type (which will be string in most cases anyway).
+        /// </summary>
+        public enum Type
+        {
+            BOOL, INTEGER, FLOATING_POINT,
+            UNDEFINED_NUMBER, STRING, DATA,
+            DATE
+        };
+
+        /// <summary>
+        ///     A null-implementation of a preprocessor for registered, but passive, use cases.
+        /// </summary>
+        private static T NullPreprocessor<T>(T value) => value;
+
+        private record struct TypeIdentifier(Type ValueType, System.Type DataType);
+
+        /// <summary>
+        ///     Default preprocessors for all the standard cases.
+        /// </summary>
+        private static readonly Dictionary<TypeIdentifier, Delegate> _preprocessors = new()
+        {
+            { new TypeIdentifier(Type.BOOL, typeof(bool)), NullPreprocessor<bool> },
+            { new TypeIdentifier(Type.BOOL, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.INTEGER, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.INTEGER, typeof(byte[])), NullPreprocessor<byte[]> },
+            { new TypeIdentifier(Type.FLOATING_POINT, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.FLOATING_POINT, typeof(byte[])), NullPreprocessor<byte[]> },
+            { new TypeIdentifier(Type.UNDEFINED_NUMBER, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.STRING, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.STRING, typeof(byte[])), NullPreprocessor<byte[]> },
+            { new TypeIdentifier(Type.DATA, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.DATA, typeof(byte[])), NullPreprocessor<byte[]> },
+            { new TypeIdentifier(Type.DATE, typeof(string)), NullPreprocessor<string> },
+            { new TypeIdentifier(Type.DATE, typeof(double)), NullPreprocessor<double> },
+            { new TypeIdentifier(Type.DATE, typeof(byte[])), NullPreprocessor<byte[]> },
+        };
+
+        /// <summary>
+        ///     Get a default preprocessor.
+        /// </summary>
+        public static Func<T, T> GetDefault<T>() => NullPreprocessor<T>;
+
+        /// <summary>
+        ///     Set up a custom preprocessor.
+        /// </summary>
+        public static void Set<T>(Func<T, T> preprocessor, Type type) =>
+            _preprocessors[new(type, typeof(T))] = preprocessor;
+
+        
+        /// <summary>
+        ///     Unset a specific preprocessor--replaces it with a null-implementation
+        ///     to prevent argument errors.
+        /// </summary>
+        /// <exception cref="ArgumentException">If no appropriate preprocessor--not even a default null-implementation--was set up.</exception>
+        public static void Unset<T>(Type type) => 
+            _preprocessors[GetValidTypeIdentifier<T>(type)] = NullPreprocessor<T>;
+
+        /// <summary>
+        ///     Completely unregister a specific preprocessor--remove it instead of
+        ///     replacing it with a null-implementation.
+        /// </summary>
+        /// <exception cref="ArgumentException">If no appropriate preprocessor--not even a default null-implementation--was registered.</exception>
+        public static void Remove<T>(Type type) => 
+            _preprocessors.Remove(GetValidTypeIdentifier<T>(type));
+
+        /// <summary>
+        ///     Preprocess the supplied data using the appropriate registered implementation.
+        /// </summary>
+        /// <exception cref="ArgumentException">If no appropriate preprocessor--not even a default null-implementation--was registered.</exception>
+        public static T Preprocess<T>(T value, Type type) => TryGetPreprocessor(type, out Func<T, T> preprocess)
+            ? preprocess(value)
+            : throw new ArgumentException($"Failed to find a preprocessor for value '{value}'.");
+
+        /// <summary>
+        ///     Gets the appropriate registered implementation--or null--and casts it back to
+        ///     the required type.
+        /// </summary>
+        private static bool TryGetPreprocessor<T>(Type type, out Func<T, T> preprocess)
+        {
+            if(_preprocessors.TryGetValue(new TypeIdentifier(type, typeof(T)), out Delegate preprocessor))
+            {
+                preprocess = (Func<T, T>)preprocessor;
+
+                return true;
+            }
+
+            preprocess = default;
+
+            return false;
+        }
+
+        /// <summary>
+        ///     Gets a type identifier if a preprocessor exists for it.
+        /// </summary>
+        /// <exception cref="ArgumentException">If no appropriate preprocessor--not even a default null-implementation--was set up.</exception>
+        private static TypeIdentifier GetValidTypeIdentifier<T>(Type type)
+        {
+            var identifier = new TypeIdentifier(type, typeof(T));
+
+            if(!_preprocessors.ContainsKey(identifier))
+            {
+                throw new ArgumentException($"Failed to find a valid preprocessor type identifier.");
+            }
+
+            return identifier;
+        }
+    }
+}

plist-cil/XmlPropertyListParser.cs

@@ -173,13 +173,13 @@ namespace Claunia.PropertyList
 
                     return array;
                 }
-                case "true":    return new NSNumber(true);
-                case "false":   return new NSNumber(false);
-                case "integer": return new NSNumber(GetNodeTextContents(n), NSNumber.INTEGER);
-                case "real":    return new NSNumber(GetNodeTextContents(n), NSNumber.REAL);
-                case "string":  return new NSString(GetNodeTextContents(n));
-                case "data":    return new NSData(GetNodeTextContents(n));
-                default:        return n.Name.Equals("date") ? new NSDate(GetNodeTextContents(n)) : null;
+                case "true":    return new NSNumber(ValuePreprocessor.Preprocess(true, ValuePreprocessor.Type.BOOL));
+                case "false":   return new NSNumber(ValuePreprocessor.Preprocess(false, ValuePreprocessor.Type.BOOL));
+                case "integer": return new NSNumber(ValuePreprocessor.Preprocess(GetNodeTextContents(n), ValuePreprocessor.Type.INTEGER), NSNumber.INTEGER);
+                case "real":    return new NSNumber(ValuePreprocessor.Preprocess(GetNodeTextContents(n), ValuePreprocessor.Type.FLOATING_POINT), NSNumber.REAL);
+                case "string":  return new NSString(ValuePreprocessor.Preprocess(GetNodeTextContents(n), ValuePreprocessor.Type.STRING));
+                case "data":    return new NSData(ValuePreprocessor.Preprocess(GetNodeTextContents(n), ValuePreprocessor.Type.DATA));
+                default:        return n.Name.Equals("date") ? new NSDate(ValuePreprocessor.Preprocess(GetNodeTextContents(n), ValuePreprocessor.Type.DATE)) : null;
             }
         }