Namespace Metalama.Extensions.Interceptors

This namespace allows you to intercept the calls to methods of any assembly, and to redirect them to an existing method or to a method generated from a T# template.

Conceptual documentation

Refer to Interceptors.

Overview

Aspects and fabrics register interceptors with the InterceptMethods extension methods of InterceptionAdviserExtensions and InterceptionQueryExtensions. The argument is a delegate that describes the interception as a chain of immutable values, in this order:

IMethodInterceptionBuilder sets the calling code, and selects the type that declares the intercepted methods.
ITypeSelection and ITypeFilterSelection select the methods.
IMethodSelection filters the methods, and chooses the interceptor through IMethodResultFactory, or decides for each call site with ForEachSite.
IExistingMethodInterception or ITemplateInterception sets the options of the interceptor.

A template reads the description of the interception through the meta.Interception property, of type IInterceptionInfo.

The ExcludeInterceptorsAttribute attribute and the InterceptorConfigurationExtensions extension methods exclude code from interception.

Class diagram

classDiagram
    class IMethodInterceptionBuilder {
        IncludingNestedTypes()
        ExcludingLambdas()
        Type()
        Types()
    }
    class ITypeFilterSelection {
        Methods()
    }
    class ITypeSelection {
        AllMethods()
    }
    class IMethodResultFactory {
        RedirectToExistingMethod()
        RedirectToSynthesizedMethod()
    }
    class IMethodSelection {
        Where()
        IncludingInterfaceImplementations()
        ExcludingOverrides()
        ForEachSite()
    }
    class IMethodInterceptionSite {
        Skip()
    }
    class IMethodInterception
    class IExistingMethodInterception {
        WithArgs()
    }
    class ITemplateInterception {
        WithArgs()
        WithTags()
        WithTemplateProvider()
        PlaceInStaticClass()
        PlaceInCallingType()
        PlaceInType()
        WithGranularity()
        Configure()
    }
    IMethodInterceptionBuilder --> ITypeSelection : Type()
    IMethodInterceptionBuilder --> ITypeFilterSelection : Types()
    ITypeSelection --|> ITypeFilterSelection
    ITypeFilterSelection --> IMethodSelection : Methods()
    IMethodSelection --|> IMethodResultFactory
    IMethodInterceptionSite --|> IMethodResultFactory
    IMethodResultFactory --> IExistingMethodInterception
    IMethodResultFactory --> ITemplateInterception
    IExistingMethodInterception --|> IMethodInterception
    ITemplateInterception --|> IMethodInterception

Classes

ExcludeInterceptorsAttribute

Excludes the code of the declaration from interception, or includes it again: when excluded, no site inside the declaration, or inside a declaration that it contains, is presented to any interceptor registration.

InterceptionAdviserExtensions

Provides extension methods that register interceptors from an aspect or a type fabric. The scope is the target of the adviser: a compilation, a namespace, a type or a member.

InterceptionMetaExtensions

Extends meta with the information about interceptions.

InterceptionQueryExtensions

Provides extension methods that register interceptors through a query. Each declaration selected by the query is a scope: the uses of the selected methods located in its code are intercepted.

InterceptorConfigurationExtensions

Extension methods that configure interception from a fabric, for the declarations that a query selects.

Structs

InterceptorReceiverEligibility

Describes whether the receiver of a call can or must be mapped to the this of the generated interceptor method, that is, whether ReceiverMapping can or must be This. The ReceiverEligibility property gives it.

InvocationArgument

Describes the argument passed to one parameter at a call site.

Interfaces

ICaller

Describes the code that contains a site: the member, the kind of code and the function.

IConfiguredTemplateInterception

A method interception whose calls are redirected to a method synthesized from a template, after the first call of Configure(Action<IInterceptorMethodBuilder>). It is a complete interception, which the delegate given to InterceptMethods or to ForEachSite(Func<IMethodInterceptionSite, IMethodInterception>) can return.

IExistingMethodInterception

A method interception whose calls are redirected to an existing method, created by RedirectToExistingMethod(IMethod). It is a complete interception, which the delegate given to InterceptMethods or to ForEachSite(Func<IMethodInterceptionSite, IMethodInterception>) can return.

IInterceptionContext

The base interface of the contexts of a call site. It describes one site. IMethodInterceptionSite and Context implement or expose it.

IInterceptionInfo

Describes the interception that a template implements. A template reads it through the meta.Interception property.

IInterceptorMethodBuilder

Lets the delegate given to Configure(Action<IInterceptorMethodBuilder>) shape the interceptor method that a template generates for a method call.

IInvocationReceiver

Describes the receiver written at a site: the object on which the method is called or from which the method group is taken.

IMethodInterception

A complete description of a method interception, or of the interception of one call site. The delegate given to InterceptMethods returns it, and so does the delegate given to ForEachSite(Func<IMethodInterceptionSite, IMethodInterception>).

IMethodInterceptionBuilder

The first stage of the description of a method interception, which the delegate given to InterceptMethods receives. It sets where the call sites are, and then selects the type that declares the intercepted methods.

IMethodInterceptionContext

Describes one use of a method that a method registration selects: a call, or a method group converted to a delegate, added to or removed from an event, or converted to a function pointer.

IMethodInterceptionInfo

Describes the interception of a method call that a template implements, as given by the Method property.

IMethodInterceptionSite

One call site in the delegate given to ForEachSite(Func<IMethodInterceptionSite, IMethodInterception>). It describes the site, through the members of IMethodInterceptionContext, and creates the result of the site.

IMethodResultFactory

Chooses how the selected calls are intercepted: redirected to an existing method, or redirected to a method synthesized from a template. It is the base of IMethodSelection, for a result that applies to every call site, and of IMethodInterceptionSite, for the result of one call site.

IMethodSelection

The stage of a method interception at which the intercepted methods are selected. It filters the methods, decides whether the calls bound to their overrides and to their interface implementations match, and then chooses how the calls are intercepted.

ITemplateInterception

A method interception whose calls are redirected to a method synthesized from a template. Its methods set the options of the synthesized method. It is a complete interception, which the delegate given to InterceptMethods or to ForEachSite(Func<IMethodInterceptionSite, IMethodInterception>) can return.

ITypeFilterSelection

The stage of a method interception at which the types that declare the intercepted methods are selected by a predicate. The methods must be given by name.

ITypeSelection

The stage of a method interception at which one type that declares the intercepted methods is selected.