JetBrains.Annotations.cs

Go to the documentation of this file.

using System;

#pragma warning disable 1591
// ReSharper disable UnusedMember.Global
// ReSharper disable UnusedParameter.Local
// ReSharper disable MemberCanBePrivate.Global
// ReSharper disable UnusedAutoPropertyAccessor.Global
// ReSharper disable IntroduceOptionalParameters.Global
// ReSharper disable MemberCanBeProtected.Global
// ReSharper disable InconsistentNaming
// ReSharper disable CheckNamespace

namespace JetBrains.Annotations
{
    /// <summary>
    /// Indicates that the value of the marked element could be <c>null</c> sometimes,
    /// so the check for <c>null</c> is necessary before its usage
    /// </summary>
    /// <example><code>
    /// [CanBeNull] public object Test() { return null; }
    /// public void UseTest() {
    ///   var p = Test();
    ///   var s = p.ToString(); // Warning: Possible 'System.NullReferenceException'
    /// }
    /// </code></example>
    [AttributeUsage(
      AttributeTargets.Method | AttributeTargets.Parameter |
      AttributeTargets.Property | AttributeTargets.Delegate |
      AttributeTargets.Field, AllowMultiple = false, Inherited = true)]
    internal sealed class CanBeNullAttribute : Attribute { }

    /// <summary>
    /// Indicates that the value of the marked element could never be <c>null</c>
    /// </summary>
    /// <example><code>
    /// [NotNull] public object Foo() {
    ///   return null; // Warning: Possible 'null' assignment
    /// }
    /// </code></example>
    [AttributeUsage(
      AttributeTargets.Method | AttributeTargets.Parameter |
      AttributeTargets.Property | AttributeTargets.Delegate |
      AttributeTargets.Field, AllowMultiple = false, Inherited = true)]
    internal sealed class NotNullAttribute : Attribute { }

    /// <summary>
    /// Indicates that the marked method builds string by format pattern and (optional) arguments.
    /// Parameter, which contains format string, should be given in constructor. The format string
    /// should be in <see cref="string.Format(IFormatProvider,string,object[])"/>-like form
    /// </summary>
    /// <example><code>
    /// [StringFormatMethod("message")]
    /// public void ShowError(string message, params object[] args) { /* do something */ }
    /// public void Foo() {
    ///   ShowError("Failed: {0}"); // Warning: Non-existing argument in format string
    /// }
    /// </code></example>
    [AttributeUsage(
      AttributeTargets.Constructor | AttributeTargets.Method,
      AllowMultiple = false, Inherited = true)]
    internal sealed class StringFormatMethodAttribute : Attribute
    {
        /// <param name="formatParameterName">
        /// Specifies which parameter of an annotated method should be treated as format-string
        /// </param>
        public StringFormatMethodAttribute(string formatParameterName)
        {
            FormatParameterName = formatParameterName;
        }

        public string FormatParameterName { get; private set; }
    }

    /// <summary>
    /// Indicates that the function argument should be string literal and match one
    /// of the parameters of the caller function. For example, ReSharper annotates
    /// the parameter of <see cref="System.ArgumentNullException"/>
    /// </summary>
    /// <example><code>
    /// public void Foo(string param) {
    ///   if (param == null)
    ///     throw new ArgumentNullException("par"); // Warning: Cannot resolve symbol
    /// }
    /// </code></example>
    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = true)]
    internal sealed class InvokerParameterNameAttribute : Attribute { }

    /// <summary>
    /// Indicates that the method is contained in a type that implements
    /// <see cref="System.ComponentModel.INotifyPropertyChanged"/> interface
    /// and this method is used to notify that some property value changed
    /// </summary>
    /// <remarks>
    /// The method should be non-static and conform to one of the supported signatures:
    /// <list>
    /// <item><c>NotifyChanged(string)</c></item>
    /// <item><c>NotifyChanged(params string[])</c></item>
    /// <item><c>NotifyChanged{T}(Expression{Func{T}})</c></item>
    /// <item><c>NotifyChanged{T,U}(Expression{Func{T,U}})</c></item>
    /// <item><c>SetProperty{T}(ref T, T, string)</c></item>
    /// </list>
    /// </remarks>
    /// <example><code>
    /// public class Foo : INotifyPropertyChanged {
    ///   public event PropertyChangedEventHandler PropertyChanged;
    ///   [NotifyPropertyChangedInvocator]
    ///   protected virtual void NotifyChanged(string propertyName) { ... }
    ///
    ///   private string _name;
    ///   public string Name {
    ///     get { return _name; }
    ///     set { _name = value; NotifyChanged("LastName"); /* Warning */ }
    ///   }
    /// }
    /// </code>
    /// Examples of generated notifications:
    /// <list>
    /// <item><c>NotifyChanged("Property")</c></item>
    /// <item><c>NotifyChanged(() =&gt; Property)</c></item>
    /// <item><c>NotifyChanged((VM x) =&gt; x.Property)</c></item>
    /// <item><c>SetProperty(ref myField, value, "Property")</c></item>
    /// </list>
    /// </example>
    [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
    internal sealed class NotifyPropertyChangedInvocatorAttribute : Attribute
    {
        public NotifyPropertyChangedInvocatorAttribute() { }
        public NotifyPropertyChangedInvocatorAttribute(string parameterName)
        {
            ParameterName = parameterName;
        }

        public string ParameterName { get; private set; }
    }

    /// <summary>
    /// Describes dependency between method input and output
    /// </summary>
    /// <syntax>
    /// <p>Function Definition Table syntax:</p>
    /// <list>
    /// <item>FDT      ::= FDTRow [;FDTRow]*</item>
    /// <item>FDTRow   ::= Input =&gt; Output | Output &lt;= Input</item>
    /// <item>Input    ::= ParameterName: Value [, Input]*</item>
    /// <item>Output   ::= [ParameterName: Value]* {halt|stop|void|nothing|Value}</item>
    /// <item>Value    ::= true | false | null | notnull | canbenull</item>
    /// </list>
    /// If method has single input parameter, it's name could be omitted.<br/>
    /// Using <c>halt</c> (or <c>void</c>/<c>nothing</c>, which is the same)
    /// for method output means that the methos doesn't return normally.<br/>
    /// <c>canbenull</c> annotation is only applicable for output parameters.<br/>
    /// You can use multiple <c>[ContractAnnotation]</c> for each FDT row,
    /// or use single attribute with rows separated by semicolon.<br/>
    /// </syntax>
    /// <examples><list>
    /// <item><code>
    /// [ContractAnnotation("=> halt")]
    /// public void TerminationMethod()
    /// </code></item>
    /// <item><code>
    /// [ContractAnnotation("halt &lt;= condition: false")]
    /// public void Assert(bool condition, string text) // regular assertion method
    /// </code></item>
    /// <item><code>
    /// [ContractAnnotation("s:null => true")]
    /// public bool IsNullOrEmpty(string s) // string.IsNullOrEmpty()
    /// </code></item>
    /// <item><code>
    /// // A method that returns null if the parameter is null, and not null if the parameter is not null
    /// [ContractAnnotation("null => null; notnull => notnull")]
    /// public object Transform(object data) 
    /// </code></item>
    /// <item><code>
    /// [ContractAnnotation("s:null=>false; =>true,result:notnull; =>false, result:null")]
    /// public bool TryParse(string s, out Person result)
    /// </code></item>
    /// </list></examples>
    [AttributeUsage(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
    internal sealed class ContractAnnotationAttribute : Attribute
    {
        public ContractAnnotationAttribute([NotNull] string contract)
            : this(contract, false) { }

        public ContractAnnotationAttribute([NotNull] string contract, bool forceFullStates)
        {
            Contract = contract;
            ForceFullStates = forceFullStates;
        }

        public string Contract { get; private set; }
        public bool ForceFullStates { get; private set; }
    }

    /// <summary>
    /// Indicates that marked element should be localized or not
    /// </summary>
    /// <example><code>
    /// [LocalizationRequiredAttribute(true)]
    /// public class Foo {
    ///   private string str = "my string"; // Warning: Localizable string
    /// }
    /// </code></example>
    [AttributeUsage(AttributeTargets.All, AllowMultiple = false, Inherited = true)]
    internal sealed class LocalizationRequiredAttribute : Attribute
    {
        public LocalizationRequiredAttribute() : this(true) { }
        public LocalizationRequiredAttribute(bool required)
        {
            Required = required;
        }

        public bool Required { get; private set; }
    }

    /// <summary>
    /// Indicates that the value of the marked type (or its derivatives)
    /// cannot be compared using '==' or '!=' operators and <c>Equals()</c>
    /// should be used instead. However, using '==' or '!=' for comparison
    /// with <c>null</c> is always permitted.
    /// </summary>
    /// <example><code>
    /// [CannotApplyEqualityOperator]
    /// class NoEquality { }
    /// class UsesNoEquality {
    ///   public void Test() {
    ///     var ca1 = new NoEquality();
    ///     var ca2 = new NoEquality();
    ///     if (ca1 != null) { // OK
    ///       bool condition = ca1 == ca2; // Warning
    ///     }
    ///   }
    /// }
    /// </code></example>
    [AttributeUsage(
      AttributeTargets.Interface | AttributeTargets.Class |
      AttributeTargets.Struct, AllowMultiple = false, Inherited = true)]
    internal sealed class CannotApplyEqualityOperatorAttribute : Attribute { }

    /// <summary>
    /// When applied to a target attribute, specifies a requirement for any type marked
    /// with the target attribute to implement or inherit specific type or types.
    /// </summary>
    /// <example><code>
    /// [BaseTypeRequired(typeof(IComponent)] // Specify requirement
    /// public class ComponentAttribute : Attribute { }
    /// [Component] // ComponentAttribute requires implementing IComponent interface
    /// public class MyComponent : IComponent { }
    /// </code></example>
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
    [BaseTypeRequired(typeof(Attribute))]
    internal sealed class BaseTypeRequiredAttribute : Attribute
    {
        public BaseTypeRequiredAttribute([NotNull] Type baseType)
        {
            BaseType = baseType;
        }

        [NotNull]
        public Type BaseType { get; private set; }
    }

    /// <summary>
    /// Indicates that the marked symbol is used implicitly
    /// (e.g. via reflection, in external library), so this symbol
    /// will not be marked as unused (as well as by other usage inspections)
    /// </summary>
    [AttributeUsage(AttributeTargets.All, AllowMultiple = false, Inherited = true)]
    internal sealed class UsedImplicitlyAttribute : Attribute
    {
        public UsedImplicitlyAttribute()
            : this(ImplicitUseKindFlags.Default, ImplicitUseTargetFlags.Default) { }

        public UsedImplicitlyAttribute(ImplicitUseKindFlags useKindFlags)
            : this(useKindFlags, ImplicitUseTargetFlags.Default) { }

        public UsedImplicitlyAttribute(ImplicitUseTargetFlags targetFlags)
            : this(ImplicitUseKindFlags.Default, targetFlags) { }

        public UsedImplicitlyAttribute(
          ImplicitUseKindFlags useKindFlags, ImplicitUseTargetFlags targetFlags)
        {
            UseKindFlags = useKindFlags;
            TargetFlags = targetFlags;
        }

        public ImplicitUseKindFlags UseKindFlags { get; private set; }
        public ImplicitUseTargetFlags TargetFlags { get; private set; }
    }

    /// <summary>
    /// Should be used on attributes and causes ReSharper
    /// to not mark symbols marked with such attributes as unused
    /// (as well as by other usage inspections)
    /// </summary>
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
    internal sealed class MeansImplicitUseAttribute : Attribute
    {
        public MeansImplicitUseAttribute()
            : this(ImplicitUseKindFlags.Default, ImplicitUseTargetFlags.Default) { }

        public MeansImplicitUseAttribute(ImplicitUseKindFlags useKindFlags)
            : this(useKindFlags, ImplicitUseTargetFlags.Default) { }

        public MeansImplicitUseAttribute(ImplicitUseTargetFlags targetFlags)
            : this(ImplicitUseKindFlags.Default, targetFlags) { }

        public MeansImplicitUseAttribute(
          ImplicitUseKindFlags useKindFlags, ImplicitUseTargetFlags targetFlags)
        {
            UseKindFlags = useKindFlags;
            TargetFlags = targetFlags;
        }

        [UsedImplicitly]
        public ImplicitUseKindFlags UseKindFlags { get; private set; }
        [UsedImplicitly]
        public ImplicitUseTargetFlags TargetFlags { get; private set; }
    }

    [Flags]
    internal enum ImplicitUseKindFlags
    {
        Default = Access | Assign | InstantiatedWithFixedConstructorSignature,
        /// <summary>Only entity marked with attribute considered used</summary>
        Access = 1,
        /// <summary>Indicates implicit assignment to a member</summary>
        Assign = 2,
        /// <summary>
        /// Indicates implicit instantiation of a type with fixed constructor signature.
        /// That means any unused constructor parameters won't be reported as such.
        /// </summary>
        InstantiatedWithFixedConstructorSignature = 4,
        /// <summary>Indicates implicit instantiation of a type</summary>
        InstantiatedNoFixedConstructorSignature = 8,
    }

    /// <summary>
    /// Specify what is considered used implicitly
    /// when marked with <see cref="MeansImplicitUseAttribute"/>
    /// or <see cref="UsedImplicitlyAttribute"/>
    /// </summary>
    [Flags]
    internal enum ImplicitUseTargetFlags
    {
        Default = Itself,
        Itself = 1,
        /// <summary>Members of entity marked with attribute are considered used</summary>
        Members = 2,
        /// <summary>Entity marked with attribute and all its members considered used</summary>
        WithMembers = Itself | Members
    }

    /// <summary>
    /// This attribute is intended to mark publicly available API
    /// which should not be removed and so is treated as used
    /// </summary>
    [MeansImplicitUse]
    internal sealed class PublicAPIAttribute : Attribute
    {
        public PublicAPIAttribute() { }
        public PublicAPIAttribute([NotNull] string comment)
        {
            Comment = comment;
        }

        [NotNull]
        public string Comment { get; private set; }
    }

    /// <summary>
    /// Tells code analysis engine if the parameter is completely handled
    /// when the invoked method is on stack. If the parameter is a delegate,
    /// indicates that delegate is executed while the method is executed.
    /// If the parameter is an enumerable, indicates that it is enumerated
    /// while the method is executed
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter, Inherited = true)]
    internal sealed class InstantHandleAttribute : Attribute { }

    /// <summary>
    /// Indicates that a method does not make any observable state changes.
    /// The same as <c>System.Diagnostics.Contracts.PureAttribute</c>
    /// </summary>
    /// <example><code>
    /// [Pure] private int Multiply(int x, int y) { return x * y; }
    /// public void Foo() {
    ///   const int a = 2, b = 2;
    ///   Multiply(a, b); // Waring: Return value of pure method is not used
    /// }
    /// </code></example>
    [AttributeUsage(AttributeTargets.Method, Inherited = true)]
    internal sealed class PureAttribute : Attribute { }

    /// <summary>
    /// Indicates that a parameter is a path to a file or a folder
    /// within a web project. Path can be relative or absolute,
    /// starting from web root (~)
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal class PathReferenceAttribute : Attribute
    {
        public PathReferenceAttribute() { }
        public PathReferenceAttribute([PathReference] string basePath)
        {
            BasePath = basePath;
        }

        [NotNull]
        public string BasePath { get; private set; }
    }

    // ASP.NET MVC attributes

    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
    internal sealed class AspMvcAreaMasterLocationFormatAttribute : Attribute
    {
        public AspMvcAreaMasterLocationFormatAttribute(string format) { }
    }

    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
    internal sealed class AspMvcAreaPartialViewLocationFormatAttribute : Attribute
    {
        public AspMvcAreaPartialViewLocationFormatAttribute(string format) { }
    }

    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
    internal sealed class AspMvcAreaViewLocationFormatAttribute : Attribute
    {
        public AspMvcAreaViewLocationFormatAttribute(string format) { }
    }

    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
    internal sealed class AspMvcMasterLocationFormatAttribute : Attribute
    {
        public AspMvcMasterLocationFormatAttribute(string format) { }
    }

    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
    internal sealed class AspMvcPartialViewLocationFormatAttribute : Attribute
    {
        public AspMvcPartialViewLocationFormatAttribute(string format) { }
    }

    [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = true)]
    internal sealed class AspMvcViewLocationFormatAttribute : Attribute
    {
        public AspMvcViewLocationFormatAttribute(string format) { }
    }

    /// <summary>
    /// ASP.NET MVC attribute. If applied to a parameter, indicates that the parameter
    /// is an MVC action. If applied to a method, the MVC action name is calculated
    /// implicitly from the context. Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Html.ChildActionExtensions.RenderAction(HtmlHelper, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Method)]
    internal sealed class AspMvcActionAttribute : Attribute
    {
        public AspMvcActionAttribute() { }
        public AspMvcActionAttribute([NotNull] string anonymousProperty)
        {
            AnonymousProperty = anonymousProperty;
        }

        [NotNull]
        public string AnonymousProperty { get; private set; }
    }

    /// <summary>
    /// ASP.NET MVC attribute. Indicates that a parameter is an MVC area.
    /// Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Html.ChildActionExtensions.RenderAction(HtmlHelper, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal sealed class AspMvcAreaAttribute : PathReferenceAttribute
    {
        public AspMvcAreaAttribute() { }
        public AspMvcAreaAttribute([NotNull] string anonymousProperty)
        {
            AnonymousProperty = anonymousProperty;
        }

        [NotNull]
        public string AnonymousProperty { get; private set; }
    }

    /// <summary>
    /// ASP.NET MVC attribute. If applied to a parameter, indicates that
    /// the parameter is an MVC controller. If applied to a method,
    /// the MVC controller name is calculated implicitly from the context.
    /// Use this attribute for custom wrappers similar to 
    /// <c>System.Web.Mvc.Html.ChildActionExtensions.RenderAction(HtmlHelper, String, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Method)]
    internal sealed class AspMvcControllerAttribute : Attribute
    {
        public AspMvcControllerAttribute() { }
        public AspMvcControllerAttribute([NotNull] string anonymousProperty)
        {
            AnonymousProperty = anonymousProperty;
        }

        [NotNull]
        public string AnonymousProperty { get; private set; }
    }

    /// <summary>
    /// ASP.NET MVC attribute. Indicates that a parameter is an MVC Master.
    /// Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Controller.View(String, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal sealed class AspMvcMasterAttribute : Attribute { }

    /// <summary>
    /// ASP.NET MVC attribute. Indicates that a parameter is an MVC model type.
    /// Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Controller.View(String, Object)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal sealed class AspMvcModelTypeAttribute : Attribute { }

    /// <summary>
    /// ASP.NET MVC attribute. If applied to a parameter, indicates that
    /// the parameter is an MVC partial view. If applied to a method,
    /// the MVC partial view name is calculated implicitly from the context.
    /// Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(HtmlHelper, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Method)]
    internal sealed class AspMvcPartialViewAttribute : PathReferenceAttribute { }

    /// <summary>
    /// ASP.NET MVC attribute. Allows disabling all inspections
    /// for MVC views within a class or a method.
    /// </summary>
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
    internal sealed class AspMvcSupressViewErrorAttribute : Attribute { }

    /// <summary>
    /// ASP.NET MVC attribute. Indicates that a parameter is an MVC display template.
    /// Use this attribute for custom wrappers similar to 
    /// <c>System.Web.Mvc.Html.DisplayExtensions.DisplayForModel(HtmlHelper, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal sealed class AspMvcDisplayTemplateAttribute : Attribute { }

    /// <summary>
    /// ASP.NET MVC attribute. Indicates that a parameter is an MVC editor template.
    /// Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Html.EditorExtensions.EditorForModel(HtmlHelper, String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal sealed class AspMvcEditorTemplateAttribute : Attribute { }

    /// <summary>
    /// ASP.NET MVC attribute. Indicates that a parameter is an MVC template.
    /// Use this attribute for custom wrappers similar to
    /// <c>System.ComponentModel.DataAnnotations.UIHintAttribute(System.String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter)]
    internal sealed class AspMvcTemplateAttribute : Attribute { }

    /// <summary>
    /// ASP.NET MVC attribute. If applied to a parameter, indicates that the parameter
    /// is an MVC view. If applied to a method, the MVC view name is calculated implicitly
    /// from the context. Use this attribute for custom wrappers similar to
    /// <c>System.Web.Mvc.Controller.View(Object)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Method)]
    internal sealed class AspMvcViewAttribute : PathReferenceAttribute { }

    /// <summary>
    /// ASP.NET MVC attribute. When applied to a parameter of an attribute,
    /// indicates that this parameter is an MVC action name
    /// </summary>
    /// <example><code>
    /// [ActionName("Foo")]
    /// public ActionResult Login(string returnUrl) {
    ///   ViewBag.ReturnUrl = Url.Action("Foo"); // OK
    ///   return RedirectToAction("Bar"); // Error: Cannot resolve action
    /// }
    /// </code></example>
    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property)]
    internal sealed class AspMvcActionSelectorAttribute : Attribute { }

    [AttributeUsage(
      AttributeTargets.Parameter | AttributeTargets.Property |
      AttributeTargets.Field, Inherited = true)]
    internal sealed class HtmlElementAttributesAttribute : Attribute
    {
        public HtmlElementAttributesAttribute() { }
        public HtmlElementAttributesAttribute([NotNull] string name)
        {
            Name = name;
        }

        [NotNull]
        public string Name { get; private set; }
    }

    [AttributeUsage(
      AttributeTargets.Parameter | AttributeTargets.Field |
      AttributeTargets.Property, Inherited = true)]
    internal sealed class HtmlAttributeValueAttribute : Attribute
    {
        public HtmlAttributeValueAttribute([NotNull] string name)
        {
            Name = name;
        }

        [NotNull]
        public string Name { get; private set; }
    }

    // Razor attributes

    /// <summary>
    /// Razor attribute. Indicates that a parameter or a method is a Razor section.
    /// Use this attribute for custom wrappers similar to 
    /// <c>System.Web.WebPages.WebPageBase.RenderSection(String)</c>
    /// </summary>
    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Method, Inherited = true)]
    internal sealed class RazorSectionAttribute : Attribute { }
}