public static FieldReference FindOrInjectTrackerField(WeavingContext context, TypeDefinition type)
{
var found = FindTrackerField(type);
if (found != null)
{
return(found);
}
var field = new FieldDefinition(FieldName, FieldAttributes.FamANDAssem,
context.PropertyTrackerReference);
type.Fields.Add(field);
foreach (var ctor in type.GetConstructors())
{
using (var il = new Helper(ctor))
{
var first = ctor.Body.Instructions.First();
il.AddBefore(first, new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldflda, field },
{ OpCodes.Call, context.PropertyTrackerInitReference }
});
}
}
return(field);
}
static FieldReference FindOrInjectTrackerField(WeavingContext context, TypeDefinition type)
{
return(FindOrInjectField(context, type, TrackerFieldName, context.PropertyTrackerReference, (il, field) =>
{
var first = il.Body.Instructions.First();
il.AddBefore(first, new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldflda, field },
{ OpCodes.Call, context.PropertyTrackerInitReference }
});
}));
}
static FieldReference FindOrInjectBlazorHelperField(WeavingContext context, TypeDefinition type)
{
return(FindOrInjectField(context, type, BlazorHelperFieldName, context.BlazorComponentHelperReference,
(il, field) =>
{
il.AddBefore(il.Body.Instructions.First(), new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldfld, field },
{ OpCodes.Brtrue, il.Body.Instructions.First() },
OpCodes.Ldarg_0,
OpCodes.Ldarg_0,
{ OpCodes.Newobj, context.BlazorComponentHelperCtorReference },
{ OpCodes.Stfld, field }
});
}));
}
static FieldReference FindOrInjectField(WeavingContext context, TypeDefinition type,
string fieldName, TypeReference fieldType, Action <Helper, FieldDefinition> builder)
{
var found = FindTrackerField(type, fieldName);
if (found != null)
{
return(found);
}
var field = new FieldDefinition(fieldName, FieldAttributes.FamANDAssem, fieldType);
type.Fields.Add(field);
foreach (var ctor in type.GetConstructors())
{
using (var il = new Helper(ctor))
{
builder(il, field);
}
}
return(field);
}
static int SetNextPropertyId(WeavingContext context, TypeDefinition typeDef)
{
var existing =
typeDef.CustomAttributes.FirstOrDefault(a =>
a.AttributeType.AreEqual(context.PropertyCountAttributeReference));
if (existing != null)
{
var nextId = (int)existing.ConstructorArguments[0].Value + 1;
existing.ConstructorArguments[0] = new CustomAttributeArgument(existing.AttributeType, nextId);
return(nextId);
}
else
{
var nextId = FindBaseTypeObservablePropertyCount(typeDef) + 1;
typeDef.CustomAttributes.Add(new CustomAttribute(context.PropertyCountAttributeCtorReference)
{
ConstructorArguments =
{ new CustomAttributeArgument(context.TypeSystem.Int32Reference, nextId) }
});
return(nextId);
}
}
public static void InstrumentProperty(WeavingContext context, PropertyDefinition prop)
{
var getter = prop.GetMethod;
var setter = prop.SetMethod;
var propId = SetNextPropertyId(context, getter.DeclaringType);
var trackerField = FindOrInjectTrackerField(context, getter.DeclaringType);
using (var getterIl = new Helper(getter))
{
var getterFirst = getter.Body.Instructions.First();
getterIl.AddBefore(getterFirst, new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldflda, trackerField },
{ OpCodes.Ldc_I4, propId },
{ OpCodes.Call, context.PropertyTrackerTrackGetReference }
});
}
using (var setterIl = new Helper(setter))
{
var oldValueVariable = new VariableDefinition(prop.PropertyType);
var oldValueIsSet = new VariableDefinition(context.TypeSystem.BooleanReference);
setter.Body.Variables.Add(oldValueVariable);
setter.Body.Variables.Add(oldValueIsSet);
var originalSetterFirst = setter.Body.Instructions.First();
// Prologue
setterIl.AddBefore(originalSetterFirst, new Instructions
{
// var oldValueIsSet = false
{ OpCodes.Ldc_I4_0 },
{ OpCodes.Stloc, oldValueIsSet },
// this._tracker.EnterTrackSet();
{ OpCodes.Ldarg_0 },
{ OpCodes.Ldflda, trackerField },
{ OpCodes.Call, context.PropertyTrackerEnterTrackSetReference },
// var old = this.Property;
{ OpCodes.Ldarg_0 },
{ OpCodes.Callvirt, getter },
{ OpCodes.Stloc, oldValueVariable },
// oldValueIsSet = true
{ OpCodes.Ldc_I4_1 },
{ OpCodes.Stloc, oldValueIsSet }
});
// New final return instruction
var lastRet = Instruction.Create(OpCodes.Ret);
setterIl.Append(lastRet);
var leaveTry = Instruction.Create(OpCodes.Leave_S, lastRet);
if (lastRet.Previous.OpCode == OpCodes.Ret)
{
setterIl.Replace(lastRet.Previous, leaveTry);
}
else
{
setterIl.AddBefore(lastRet, leaveTry);
}
var genericTrackSet = new GenericInstanceMethod(context.PropertyTrackerTrackSetReference)
{
GenericArguments = { prop.PropertyType },
};
//var leaveFinally = setterIl.Create(OpCodes.Leave_S, lastRet);
var leaveFinally = Instruction.Create(OpCodes.Endfinally);
var fastFinallyInstructions = new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldflda, trackerField },
{ OpCodes.Call, context.PropertyTrackerLeaveTrackSetReference }
};
var finallyInstructions = new Instructions
{
// if(!oldValueIsSet) goto: fastFinally
{ OpCodes.Ldloc, oldValueIsSet },
{ OpCodes.Brfalse, fastFinallyInstructions.First() },
// this._tracker.TrackSet({id}, oldValue, Prop ({this._tracker.LeaveTrackSet()}))
{ OpCodes.Ldarg_0 },
{ OpCodes.Ldflda, trackerField },
{ OpCodes.Ldc_I4, propId },
{ OpCodes.Ldloc, oldValueVariable },
{ OpCodes.Ldarg_0 },
{ OpCodes.Callvirt, getter },
// this._tracker.LeaveTrackSet()
{ OpCodes.Ldarg_0 },
{ OpCodes.Ldflda, trackerField },
{ OpCodes.Call, context.PropertyTrackerLeaveTrackSetReference },
{ OpCodes.Call, genericTrackSet },
{ OpCodes.Br, leaveFinally }
};
setterIl.AddBefore(lastRet, finallyInstructions);
setterIl.AddBefore(lastRet, fastFinallyInstructions);
setterIl.AddBefore(lastRet, leaveFinally);
foreach (var i in setter.Body.Instructions.Where(x => x.OpCode == OpCodes.Ret && x != lastRet).ToList())
{
setterIl.Replace(i, Instruction.Create(OpCodes.Leave_S, lastRet));
}
setter.Body.ExceptionHandlers.Add(new ExceptionHandler(ExceptionHandlerType.Finally)
{
TryStart = setter.Body.Instructions.First(),
TryEnd = leaveTry.Next,
HandlerStart = leaveTry.Next,
HandlerEnd = leaveFinally.Next
});
setter.Body.MaxStackSize += 2;
}
}
public static void InstrumentBlazorComponent(WeavingContext context, TypeDefinition type)
{
var field = FindOrInjectBlazorHelperField(context, type);
var method = type.Methods.First(m => m.Name == "BuildRenderTree");
using (var il = new Helper(method))
{
var originalFirst = il.Body.Instructions.First();
il.AddBefore(originalFirst, new Instructions()
{
OpCodes.Ldarg_0,
{ OpCodes.Ldfld, field },
{ OpCodes.Callvirt, context.BlazorComponentHelperOnRenderEnterReference }
});
var lastRet = Instruction.Create(OpCodes.Ret);
il.Append(lastRet);
var leaveTry = Instruction.Create(OpCodes.Leave_S, lastRet);
if (lastRet.Previous.OpCode == OpCodes.Ret)
{
il.Replace(lastRet.Previous, leaveTry);
}
else
{
il.AddBefore(lastRet, leaveTry);
}
foreach (var i in method.Body.Instructions.Where(x => x.OpCode == OpCodes.Ret && x != lastRet).ToList())
{
il.Replace(i, Instruction.Create(OpCodes.Leave_S, lastRet));
}
var leaveFinally = Instruction.Create(OpCodes.Endfinally);
il.AddBefore(lastRet, leaveFinally);
il.AddBefore(leaveFinally, new Instructions()
{
OpCodes.Ldarg_0,
{ OpCodes.Ldfld, field },
{ OpCodes.Callvirt, context.BlazorComponentHelperOnRenderLeaveReference }
});
il.Body.ExceptionHandlers.Add(new ExceptionHandler(ExceptionHandlerType.Finally)
{
TryStart = originalFirst,
TryEnd = leaveTry.Next,
HandlerStart = leaveTry.Next,
HandlerEnd = leaveFinally.Next
});
}
var blazorComponent = type.FindBaseType(t =>
t.FullName == "Microsoft.AspNetCore.Blazor.Components.BlazorComponent");
if (!(type.Methods.Any(m => m.Name == "ShouldRender" && m.DeclaringType == type)))
{
var baseMethod = blazorComponent.Methods.First(m =>
m.Name == "ShouldRender" && m.Attributes.HasFlag(MethodAttributes.Virtual));
var shouldRender = CreateMethodOverride(type, baseMethod);
using (var il = new Helper(shouldRender))
{
il.Append(new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldfld, field },
{ OpCodes.Callvirt, context.BlazorComponentHelperShouldRenderReference },
OpCodes.Ret
});
}
}
var onParametersSetBase = FindClosestOverride(type, "OnParametersSet");
var onParametersSet = CreateMethodOverride(type, onParametersSetBase);
if (onParametersSetBase.DeclaringType == type)
{
onParametersSetBase.Attributes &= ~MethodAttributes.MemberAccessMask;
onParametersSetBase.Attributes |= MethodAttributes.NewSlot | MethodAttributes.Private;
onParametersSetBase.Name += "_Original_" + Guid.NewGuid().ToString().Replace("-", "");
}
using (var il = new Helper(onParametersSet))
{
var baseRef = onParametersSetBase.DeclaringType.Module == type.Module
? onParametersSetBase
: type.Module.ImportReference(onParametersSetBase);
il.Append(new Instructions
{
OpCodes.Ldarg_0,
{ OpCodes.Ldfld, field },
{ OpCodes.Callvirt, context.BlazorComponentHelperOnParametersSetReference },
OpCodes.Ldarg_0,
{ OpCodes.Call, baseRef },
OpCodes.Ret
});
}
}