private static bool InvokeManipulator(MethodDefinition def, Delegate cb)
{
if (cb.TryCastDelegate(out ILManipulator manip))
{
// The callback is an ILManipulator, or compatible to it out of the box.
HookIL hookIL = new HookIL(def);
hookIL.Invoke(manip);
return(!hookIL._ReadOnly);
}
// Check if the method accepts a HookIL from another assembly.
ParameterInfo[] args = cb.GetMethodInfo().GetParameters();
if (args.Length == 1 && args[0].ParameterType.FullName == typeof(HookIL).FullName)
{
// Instantiate it. We should rather pass a "proxy" of some sorts, but eh.
object hookIL = args[0].ParameterType.GetTypeInfo().GetConstructors()[0].Invoke(new object[] { def });
Type t_hookIL = hookIL.GetType();
t_hookIL.GetTypeInfo().GetMethod("Invoke").Invoke(hookIL, new object[] { cb });
return(!(t_hookIL.GetTypeInfo().GetField("ReadOnly")?.GetValue(hookIL) as bool? ?? false));
}
// Fallback - body and IL processor.
cb.DynamicInvoke(def.Body, def.Body.GetILProcessor());
def.RecalculateILOffsets();
def.ConvertShortLongOps();
return(true);
}
internal HookILCursor(HookIL hookil, Instruction instr)
{
HookIL = hookil;
Instr = instr;
}
internal HookILLabel(HookIL hookil, Instruction target) : this(hookil) {
Target = target;
}
// We're looking for these instructions and we want to delete all but the first one
// IL_0114: stfld int32 Terraria.Player::manaRegen
//
// IL_0119: ldarg.0
// IL_011A: ldflda valuetype [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2 Terraria.Entity::velocity
// IL_011F: ldfld float32 [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2::X
// IL_0124: ldc.r4 0.0
// IL_0129: bne.un.s IL_013D
//
// IL_012B: ldarg.0
// IL_012C: ldflda valuetype [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2 Terraria.Entity::velocity
// IL_0131: ldfld float32 [Microsoft.Xna.Framework]Microsoft.Xna.Framework.Vector2::Y
// IL_0136: ldc.r4 0.0
// IL_013B: beq.s IL_0150
//
// IL_013D: ldarg.0
// IL_013E: ldfld int32[] Terraria.Player::grappling
// IL_0143: ldc.i4.0
// IL_0144: ldelem.i4
// IL_0145: ldc.i4.0
// IL_0146: bge.s IL_0150
//
// IL_0148: ldarg.0
// IL_0149: ldfld bool Terraria.Player::manaRegenBuff
// IL_014E: brfalse.s IL_0165
private void Player_UpdateManaRegen(MonoMod.RuntimeDetour.HookGen.HookIL il)
{
HookILCursor cursor = il.At(0);
Func<Instruction, bool>[] ilToRemove = {
instruction => instruction.MatchLdarg(0),
instruction => instruction.MatchLdflda<Entity>("velocity"),
instruction => instruction.MatchLdfld<Vector2>("X"),
instruction => instruction.MatchLdcR4(0.0f),
instruction => instruction.Match(OpCodes.Bne_Un_S),
instruction => instruction.MatchLdarg(0),
instruction => instruction.MatchLdflda<Entity>("velocity"),
instruction => instruction.MatchLdfld<Vector2>("Y"),
instruction => instruction.MatchLdcR4(0.0f),
instruction => instruction.Match(OpCodes.Beq_S),
instruction => instruction.MatchLdarg(0),
instruction => instruction.MatchLdfld<Player>("grappling"),
instruction => instruction.MatchLdcI4(0),
instruction => instruction.MatchLdelemI4(),
instruction => instruction.MatchLdcI4(0),
instruction => instruction.Match(OpCodes.Bge_S),
instruction => instruction.MatchLdarg(0),
instruction => instruction.MatchLdfld<Player>("manaRegenBuff"),
instruction => instruction.Match(OpCodes.Brfalse_S)
};
bool found = false; //whether or not we have matched our 1 + 19 instructions
int attemptCount = 0; //used for logging
string loggedInstructions = "";
while (cursor.TryGotoNext(
// Look for when we store "manaRegen". This occurs just before our ilToRemove instructions
instruction => instruction.MatchStfld<Player>("manaRegen")))
{
HookILCursor backup = cursor.Clone();
found = true;
for (int i = 0; i < ilToRemove.Length; i++)
{
// Move cursor to next instruction and see if it doesn't match
cursor.GotoNext();
loggedInstructions += attemptCount + ": " + cursor.Next?.OpCode.ToString() + "\n";
if (!ilToRemove[i](cursor.Next))
{
found = false;
break;
}
}
if (!found) continue;
// We use the backup cursor which was at the original position just before the 19 instructions
backup.GotoNext();
// remove the 19 instructions
for(int i=0; i < ilToRemove.Length; i++)
{
backup.Remove();
}
break;
}
if (!found)
{
throw new Exception("Instructions not found; unable to patch. Sorry!\n" + loggedInstructions);
}
}
internal HookILLabel(HookIL hookil)
{
HookIL = hookil;
HookIL._Labels.Add(this);
}