diff options
Diffstat (limited to 'src/StardewModdingAPI/Framework/Reflection')
3 files changed, 431 insertions, 0 deletions
diff --git a/src/StardewModdingAPI/Framework/Reflection/PrivateField.cs b/src/StardewModdingAPI/Framework/Reflection/PrivateField.cs new file mode 100644 index 00000000..0bf45969 --- /dev/null +++ b/src/StardewModdingAPI/Framework/Reflection/PrivateField.cs @@ -0,0 +1,93 @@ +using System; +using System.Reflection; + +namespace StardewModdingAPI.Framework.Reflection +{ + /// <summary>A private field obtained through reflection.</summary> + /// <typeparam name="TValue">The field value type.</typeparam> + internal class PrivateField<TValue> : IPrivateField<TValue> + { + /********* + ** Properties + *********/ + /// <summary>The type that has the field.</summary> + private readonly Type ParentType; + + /// <summary>The object that has the instance field (if applicable).</summary> + private readonly object Parent; + + /// <summary>The display name shown in error messages.</summary> + private string DisplayName => $"{this.ParentType.FullName}::{this.FieldInfo.Name}"; + + + /********* + ** Accessors + *********/ + /// <summary>The reflection metadata.</summary> + public FieldInfo FieldInfo { get; } + + + /********* + ** Public methods + *********/ + /// <summary>Construct an instance.</summary> + /// <param name="parentType">The type that has the field.</param> + /// <param name="obj">The object that has the instance field (if applicable).</param> + /// <param name="field">The reflection metadata.</param> + /// <param name="isStatic">Whether the field is static.</param> + /// <exception cref="ArgumentNullException">The <paramref name="parentType"/> or <paramref name="field"/> is null.</exception> + /// <exception cref="ArgumentException">The <paramref name="obj"/> is null for a non-static field, or not null for a static field.</exception> + public PrivateField(Type parentType, object obj, FieldInfo field, bool isStatic) + { + // validate + if (parentType == null) + throw new ArgumentNullException(nameof(parentType)); + if (field == null) + throw new ArgumentNullException(nameof(field)); + if (isStatic && obj != null) + throw new ArgumentException("A static field cannot have an object instance."); + if (!isStatic && obj == null) + throw new ArgumentException("A non-static field must have an object instance."); + + // save + this.ParentType = parentType; + this.Parent = obj; + this.FieldInfo = field; + } + + /// <summary>Get the field value.</summary> + public TValue GetValue() + { + try + { + return (TValue)this.FieldInfo.GetValue(this.Parent); + } + catch (InvalidCastException) + { + throw new InvalidCastException($"Can't convert the private {this.DisplayName} field from {this.FieldInfo.FieldType.FullName} to {typeof(TValue).FullName}."); + } + catch (Exception ex) + { + throw new Exception($"Couldn't get the value of the private {this.DisplayName} field", ex); + } + } + + /// <summary>Set the field value.</summary> + //// <param name="value">The value to set.</param> + public void SetValue(TValue value) + { + try + { + this.FieldInfo.SetValue(this.Parent, value); + } + catch (InvalidCastException) + { + throw new InvalidCastException($"Can't assign the private {this.DisplayName} field a {typeof(TValue).FullName} value, must be compatible with {this.FieldInfo.FieldType.FullName}."); + } + catch (Exception ex) + { + throw new Exception($"Couldn't set the value of the private {this.DisplayName} field", ex); + } + } + } +} diff --git a/src/StardewModdingAPI/Framework/Reflection/PrivateMethod.cs b/src/StardewModdingAPI/Framework/Reflection/PrivateMethod.cs new file mode 100644 index 00000000..ba2374f4 --- /dev/null +++ b/src/StardewModdingAPI/Framework/Reflection/PrivateMethod.cs @@ -0,0 +1,99 @@ +using System; +using System.Reflection; + +namespace StardewModdingAPI.Framework.Reflection +{ + /// <summary>A private method obtained through reflection.</summary> + internal class PrivateMethod : IPrivateMethod + { + /********* + ** Properties + *********/ + /// <summary>The type that has the method.</summary> + private readonly Type ParentType; + + /// <summary>The object that has the instance method (if applicable).</summary> + private readonly object Parent; + + /// <summary>The display name shown in error messages.</summary> + private string DisplayName => $"{this.ParentType.FullName}::{this.MethodInfo.Name}"; + + + /********* + ** Accessors + *********/ + /// <summary>The reflection metadata.</summary> + public MethodInfo MethodInfo { get; } + + + /********* + ** Public methods + *********/ + /// <summary>Construct an instance.</summary> + /// <param name="parentType">The type that has the method.</param> + /// <param name="obj">The object that has the instance method(if applicable).</param> + /// <param name="method">The reflection metadata.</param> + /// <param name="isStatic">Whether the field is static.</param> + /// <exception cref="ArgumentNullException">The <paramref name="parentType"/> or <paramref name="method"/> is null.</exception> + /// <exception cref="ArgumentException">The <paramref name="obj"/> is null for a non-static method, or not null for a static method.</exception> + public PrivateMethod(Type parentType, object obj, MethodInfo method, bool isStatic) + { + // validate + if (parentType == null) + throw new ArgumentNullException(nameof(parentType)); + if (method == null) + throw new ArgumentNullException(nameof(method)); + if (isStatic && obj != null) + throw new ArgumentException("A static method cannot have an object instance."); + if (!isStatic && obj == null) + throw new ArgumentException("A non-static method must have an object instance."); + + // save + this.ParentType = parentType; + this.Parent = obj; + this.MethodInfo = method; + } + + /// <summary>Invoke the method.</summary> + /// <typeparam name="TValue">The return type.</typeparam> + /// <param name="arguments">The method arguments to pass in.</param> + public TValue Invoke<TValue>(params object[] arguments) + { + // invoke method + object result; + try + { + result = this.MethodInfo.Invoke(this.Parent, arguments); + } + catch (Exception ex) + { + throw new Exception($"Couldn't invoke the private {this.DisplayName} field", ex); + } + + // cast return value + try + { + return (TValue)result; + } + catch (InvalidCastException) + { + throw new InvalidCastException($"Can't convert the return value of the private {this.DisplayName} method from {this.MethodInfo.ReturnType.FullName} to {typeof(TValue).FullName}."); + } + } + + /// <summary>Invoke the method.</summary> + /// <param name="arguments">The method arguments to pass in.</param> + public void Invoke(params object[] arguments) + { + // invoke method + try + { + this.MethodInfo.Invoke(this.Parent, arguments); + } + catch (Exception ex) + { + throw new Exception($"Couldn't invoke the private {this.DisplayName} field", ex); + } + } + } +}
\ No newline at end of file diff --git a/src/StardewModdingAPI/Framework/Reflection/ReflectionHelper.cs b/src/StardewModdingAPI/Framework/Reflection/ReflectionHelper.cs new file mode 100644 index 00000000..38b4e357 --- /dev/null +++ b/src/StardewModdingAPI/Framework/Reflection/ReflectionHelper.cs @@ -0,0 +1,239 @@ +using System; +using System.Linq; +using System.Reflection; +using System.Runtime.Caching; + +namespace StardewModdingAPI.Framework.Reflection +{ + /// <summary>Provides helper methods for accessing private game code.</summary> + /// <remarks>This implementation searches up the type hierarchy, and caches the reflected fields and methods with a sliding expiry (to optimise performance without unnecessary memory usage).</remarks> + internal class ReflectionHelper : IReflectionHelper + { + /********* + ** Properties + *********/ + /// <summary>The cached fields and methods found via reflection.</summary> + private readonly MemoryCache Cache = new MemoryCache(typeof(ReflectionHelper).FullName); + + /// <summary>The sliding cache expiration time.</summary> + private readonly TimeSpan SlidingCacheExpiry = TimeSpan.FromMinutes(5); + + + /********* + ** Public methods + *********/ + /**** + ** Fields + ****/ + /// <summary>Get a private instance field.</summary> + /// <typeparam name="TValue">The field type.</typeparam> + /// <param name="obj">The object which has the field.</param> + /// <param name="name">The field name.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + /// <returns>Returns the field wrapper, or <c>null</c> if the field doesn't exist and <paramref name="required"/> is <c>false</c>.</returns> + public IPrivateField<TValue> GetPrivateField<TValue>(object obj, string name, bool required = true) + { + // validate + if (obj == null) + throw new ArgumentNullException(nameof(obj), "Can't get a private instance field from a null object."); + + // get field from hierarchy + IPrivateField<TValue> field = this.GetFieldFromHierarchy<TValue>(obj.GetType(), obj, name, BindingFlags.Instance | BindingFlags.NonPublic); + if (required && field == null) + throw new InvalidOperationException($"The {obj.GetType().FullName} object doesn't have a private '{name}' instance field."); + return field; + } + + /// <summary>Get a private static field.</summary> + /// <typeparam name="TValue">The field type.</typeparam> + /// <param name="type">The type which has the field.</param> + /// <param name="name">The field name.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + public IPrivateField<TValue> GetPrivateField<TValue>(Type type, string name, bool required = true) + { + // get field from hierarchy + IPrivateField<TValue> field = this.GetFieldFromHierarchy<TValue>(type, null, name, BindingFlags.NonPublic | BindingFlags.Static); + if (required && field == null) + throw new InvalidOperationException($"The {type.FullName} object doesn't have a private '{name}' static field."); + return field; + } + + /**** + ** Field values + ** (shorthand since this is the most common case) + ****/ + /// <summary>Get the value of a private instance field.</summary> + /// <typeparam name="TValue">The field type.</typeparam> + /// <param name="obj">The object which has the field.</param> + /// <param name="name">The field name.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + /// <remarks>This is a shortcut for <see cref="GetPrivateField{TValue}(object,string,bool)"/> followed by <see cref="IPrivateField{TValue}.GetValue"/>.</remarks> + public TValue GetPrivateValue<TValue>(object obj, string name, bool required = true) + { + return this.GetPrivateField<TValue>(obj, name, required).GetValue(); + } + + /// <summary>Get the value of a private static field.</summary> + /// <typeparam name="TValue">The field type.</typeparam> + /// <param name="type">The type which has the field.</param> + /// <param name="name">The field name.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + /// <remarks>This is a shortcut for <see cref="GetPrivateField{TValue}(Type,string,bool)"/> followed by <see cref="IPrivateField{TValue}.GetValue"/>.</remarks> + public TValue GetPrivateValue<TValue>(Type type, string name, bool required = true) + { + return this.GetPrivateField<TValue>(type, name, required).GetValue(); + } + + /**** + ** Methods + ****/ + /// <summary>Get a private instance method.</summary> + /// <param name="obj">The object which has the method.</param> + /// <param name="name">The field name.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + public IPrivateMethod GetPrivateMethod(object obj, string name, bool required = true) + { + // validate + if (obj == null) + throw new ArgumentNullException(nameof(obj), "Can't get a private instance method from a null object."); + + // get method from hierarchy + IPrivateMethod method = this.GetMethodFromHierarchy(obj.GetType(), obj, name, BindingFlags.Instance | BindingFlags.NonPublic); + if (required && method == null) + throw new InvalidOperationException($"The {obj.GetType().FullName} object doesn't have a private '{name}' instance method."); + return method; + } + + /// <summary>Get a private static method.</summary> + /// <param name="type">The type which has the method.</param> + /// <param name="name">The field name.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + public IPrivateMethod GetPrivateMethod(Type type, string name, bool required = true) + { + // get method from hierarchy + IPrivateMethod method = this.GetMethodFromHierarchy(type, null, name, BindingFlags.NonPublic | BindingFlags.Static); + if (required && method == null) + throw new InvalidOperationException($"The {type.FullName} object doesn't have a private '{name}' static method."); + return method; + } + + /**** + ** Methods by signature + ****/ + /// <summary>Get a private instance method.</summary> + /// <param name="obj">The object which has the method.</param> + /// <param name="name">The field name.</param> + /// <param name="argumentTypes">The argument types of the method signature to find.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + public IPrivateMethod GetPrivateMethod(object obj, string name, Type[] argumentTypes, bool required = true) + { + // validate parent + if (obj == null) + throw new ArgumentNullException(nameof(obj), "Can't get a private instance method from a null object."); + + // get method from hierarchy + PrivateMethod method = this.GetMethodFromHierarchy(obj.GetType(), obj, name, BindingFlags.Instance | BindingFlags.NonPublic, argumentTypes); + if (required && method == null) + throw new InvalidOperationException($"The {obj.GetType().FullName} object doesn't have a private '{name}' instance method with that signature."); + return method; + } + + /// <summary>Get a private static method.</summary> + /// <param name="type">The type which has the method.</param> + /// <param name="name">The field name.</param> + /// <param name="argumentTypes">The argument types of the method signature to find.</param> + /// <param name="required">Whether to throw an exception if the private field is not found.</param> + public IPrivateMethod GetPrivateMethod(Type type, string name, Type[] argumentTypes, bool required = true) + { + // get field from hierarchy + PrivateMethod method = this.GetMethodFromHierarchy(type, null, name, BindingFlags.NonPublic | BindingFlags.Static, argumentTypes); + if (required && method == null) + throw new InvalidOperationException($"The {type.FullName} object doesn't have a private '{name}' static method with that signature."); + return method; + } + + + /********* + ** Private methods + *********/ + /// <summary>Get a field from the type hierarchy.</summary> + /// <typeparam name="TValue">The expected field type.</typeparam> + /// <param name="type">The type which has the field.</param> + /// <param name="obj">The object which has the field.</param> + /// <param name="name">The field name.</param> + /// <param name="bindingFlags">The reflection binding which flags which indicates what type of field to find.</param> + private IPrivateField<TValue> GetFieldFromHierarchy<TValue>(Type type, object obj, string name, BindingFlags bindingFlags) + { + bool isStatic = bindingFlags.HasFlag(BindingFlags.Static); + FieldInfo field = this.GetCached<FieldInfo>($"field::{isStatic}::{type.FullName}::{name}", () => + { + FieldInfo fieldInfo = null; + for (; type != null && fieldInfo == null; type = type.BaseType) + fieldInfo = type.GetField(name, bindingFlags); + return fieldInfo; + }); + + return field != null + ? new PrivateField<TValue>(type, obj, field, isStatic) + : null; + } + + /// <summary>Get a method from the type hierarchy.</summary> + /// <param name="type">The type which has the method.</param> + /// <param name="obj">The object which has the method.</param> + /// <param name="name">The method name.</param> + /// <param name="bindingFlags">The reflection binding which flags which indicates what type of method to find.</param> + private IPrivateMethod GetMethodFromHierarchy(Type type, object obj, string name, BindingFlags bindingFlags) + { + bool isStatic = bindingFlags.HasFlag(BindingFlags.Static); + MethodInfo method = this.GetCached($"method::{isStatic}::{type.FullName}::{name}", () => + { + MethodInfo methodInfo = null; + for (; type != null && methodInfo == null; type = type.BaseType) + methodInfo = type.GetMethod(name, bindingFlags); + return methodInfo; + }); + + return method != null + ? new PrivateMethod(type, obj, method, isStatic: bindingFlags.HasFlag(BindingFlags.Static)) + : null; + } + + /// <summary>Get a method from the type hierarchy.</summary> + /// <param name="type">The type which has the method.</param> + /// <param name="obj">The object which has the method.</param> + /// <param name="name">The method name.</param> + /// <param name="bindingFlags">The reflection binding which flags which indicates what type of method to find.</param> + /// <param name="argumentTypes">The argument types of the method signature to find.</param> + private PrivateMethod GetMethodFromHierarchy(Type type, object obj, string name, BindingFlags bindingFlags, Type[] argumentTypes) + { + bool isStatic = bindingFlags.HasFlag(BindingFlags.Static); + MethodInfo method = this.GetCached($"method::{isStatic}::{type.FullName}::{name}({string.Join(",", argumentTypes.Select(p => p.FullName))})", () => + { + MethodInfo methodInfo = null; + for (; type != null && methodInfo == null; type = type.BaseType) + methodInfo = type.GetMethod(name, bindingFlags, null, argumentTypes, null); + return methodInfo; + }); + return method != null + ? new PrivateMethod(type, obj, method, isStatic) + : null; + } + + /// <summary>Get a method or field through the cache.</summary> + /// <typeparam name="TMemberInfo">The expected <see cref="MemberInfo"/> type.</typeparam> + /// <param name="key">The cache key.</param> + /// <param name="fetch">Fetches a new value to cache.</param> + private TMemberInfo GetCached<TMemberInfo>(string key, Func<TMemberInfo> fetch) where TMemberInfo : MemberInfo + { + // get from cache + if (this.Cache.Contains(key)) + return (TMemberInfo)this.Cache[key]; + + // fetch & cache new value + TMemberInfo result = fetch(); + this.Cache.Add(key, result, new CacheItemPolicy { SlidingExpiration = this.SlidingCacheExpiry }); + return result; + } + } +}
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