From 56e494aec527c4279d57a044cfb1c3f09c4e3a13 Mon Sep 17 00:00:00 2001
From: Albert Le Batteux <contact@albttx.tech>
Date: Fri, 24 Mar 2023 11:00:49 +0000
Subject: [PATCH] feat: exec-as-pkg

Co-authored-by: Thomas Bruyelle <thomas.bruyelle@gmail.com>
---
 pkgs/gnolang/machine.go     |  6 ++++++
 pkgs/gnolang/op_call.go     |  5 +++++
 pkgs/gnolang/values.go      | 13 +++++++++++++
 stdlibs/stdlibs.go          | 36 +++++++++++++++++++++++++-----------
 tests/file.go               |  2 +-
 tests/files/zrealm_std6.gno | 20 ++++++++++++++++++++
 6 files changed, 70 insertions(+), 12 deletions(-)
 create mode 100644 tests/files/zrealm_std6.gno

diff --git a/pkgs/gnolang/machine.go b/pkgs/gnolang/machine.go
index ac39dc2a227..87dd387d38e 100644
--- a/pkgs/gnolang/machine.go
+++ b/pkgs/gnolang/machine.go
@@ -804,6 +804,9 @@ const (
 	OpValueDecl Op = 0x90 // var/const ...
 	OpTypeDecl  Op = 0x91 // type ...
 
+	/* ContextOp */
+	OpSetContext Op = 0xA0
+
 	/* Loop (sticky) operators (>= 0xD0) */
 	OpSticky            Op = 0xD0 // not a real op.
 	OpBody              Op = 0xD1 // if/block/switch/select.
@@ -1275,6 +1278,9 @@ func (m *Machine) Run() {
 		case OpReturnCallDefers:
 			m.incrCPU(OpCPUReturnCallDefers)
 			m.doOpReturnCallDefers()
+		case OpSetContext:
+			m.incrCPU(1)
+			m.doOpSetContext()
 		default:
 			panic(fmt.Sprintf("unexpected opcode %s", op.String()))
 		}
diff --git a/pkgs/gnolang/op_call.go b/pkgs/gnolang/op_call.go
index c6f286dc930..0e4f82fc5af 100644
--- a/pkgs/gnolang/op_call.go
+++ b/pkgs/gnolang/op_call.go
@@ -407,3 +407,8 @@ func (m *Machine) doOpPanic2() {
 		m.PushOp(OpReturnCallDefers) // XXX rename, not return?
 	}
 }
+
+func (m *Machine) doOpSetContext() {
+	cv := m.PopValue().V.(ContextValue)
+	m.Context = cv.Context
+}
diff --git a/pkgs/gnolang/values.go b/pkgs/gnolang/values.go
index 227d5368eeb..ce19a9d0d30 100644
--- a/pkgs/gnolang/values.go
+++ b/pkgs/gnolang/values.go
@@ -40,6 +40,7 @@ func (*PackageValue) assertValue()     {}
 func (*NativeValue) assertValue()      {}
 func (*Block) assertValue()            {}
 func (RefValue) assertValue()          {}
+func (ContextValue) assertValue()      {}
 
 const (
 	nilStr = "nil"
@@ -62,6 +63,7 @@ var (
 	_ Value = &NativeValue{}
 	_ Value = &Block{}
 	_ Value = RefValue{}
+	_ Value = ContextValue{}
 )
 
 // ----------------------------------------
@@ -2184,6 +2186,17 @@ func (tv *TypedValue) GetSlice2(alloc *Allocator, low, high, max int) TypedValue
 	}
 }
 
+// ----------------------------------------
+// ContextValue
+
+type ContextValue struct {
+	Context interface{}
+}
+
+func (ctx ContextValue) String() string {
+	return fmt.Sprintf("%v", ctx.Context)
+}
+
 // ----------------------------------------
 // Block
 //
diff --git a/stdlibs/stdlibs.go b/stdlibs/stdlibs.go
index 4660d6d4398..bd028334086 100644
--- a/stdlibs/stdlibs.go
+++ b/stdlibs/stdlibs.go
@@ -289,18 +289,32 @@ func InjectPackage(store gno.Store, pn *gno.PackageNode) {
 				//       to support multiple concurrent contexts and advanced flows.
 				arg0 := m.LastBlock().GetParams1().TV
 				fn := arg0.GetFunc()
-				println("#####################", arg0, fn.GetType(m.Store).String())
-				//gno.Call(fn, "nil")
-				//m.Eval(gno.Call(fn))
-				// m.Eval(gno.Call(gno.FuncT(nil, nil), fn))
-				println("@@@@@@@@@@")
-				//println(fn)
 
-				/*
-					ctx := m.Context.(stdlibs.ExecContext)
-					ctx.OrigCaller = crypto.Bech32Address(addr)
-					m.Context = ctx
-				*/
+				ctx := m.Context.(ExecContext)
+				ctx.OrigCaller = ctx.OrigPkgAddr
+
+				backupContext := m.Context.(ExecContext)
+
+				m.PushValue(gno.TypedValue{
+					T: &gno.InterfaceType{},
+					V: gno.ContextValue{
+						Context: backupContext,
+					},
+				})
+				m.PushOp(gno.OpSetContext)
+
+				cx := gno.Call(gno.FuncT(nil, nil))
+				m.PushValue(gno.TypedValue{})
+				m.PushFrameCall(cx, fn, gno.TypedValue{})
+				m.PushOp(gno.OpCall)
+
+				m.PushValue(gno.TypedValue{
+					T: &gno.InterfaceType{},
+					V: gno.ContextValue{
+						Context: ctx,
+					},
+				})
+				m.PushOp(gno.OpSetContext)
 			},
 		)
 		pn.DefineNative("GetCallerAt",
diff --git a/tests/file.go b/tests/file.go
index 33afbe38ebb..640e9c55347 100644
--- a/tests/file.go
+++ b/tests/file.go
@@ -34,7 +34,7 @@ func TestMachine(store gno.Store, stdout io.Writer, pkgPath string) *gno.Machine
 func testMachineCustom(store gno.Store, pkgPath string, stdout io.Writer, maxAlloc int64, send std.Coins) *gno.Machine {
 	// FIXME: create a better package to manage this, with custom constructors
 	pkgAddr := gno.DerivePkgAddr(pkgPath)                      // the addr of the pkgPath called.
-	caller := gno.DerivePkgAddr(pkgPath)                       // NOTE: for the purpose of testing, the caller is generally the "main" package, same as pkgAddr.
+	caller := gno.DerivePkgAddr("caller")                      // NOTE: for the purpose of testing, the caller is generally the "main" package, same as pkgAddr.
 	pkgCoins := std.MustParseCoins("200000000ugnot").Add(send) // >= send.
 	banker := newTestBanker(pkgAddr.Bech32(), pkgCoins)
 	ctx := stdlibs.ExecContext{
diff --git a/tests/files/zrealm_std6.gno b/tests/files/zrealm_std6.gno
new file mode 100644
index 00000000000..36a9393b983
--- /dev/null
+++ b/tests/files/zrealm_std6.gno
@@ -0,0 +1,20 @@
+// PKGPATH: gno.land/r/std_test
+package std_test
+
+import (
+	"fmt"
+	"std"
+)
+
+func main() {
+	println(std.GetOrigCaller())
+	std.ExecAsPkg(func() {
+		println(std.GetOrigCaller())
+	})
+	println(std.GetOrigCaller())
+}
+
+// Output:
+// g1fahslvxakc058u0wa98ytfc9fd6trhe5qfh9ld
+// g157y5v3k529jyzhjjz4fn49tzzhf4gess6v39xg
+// g1fahslvxakc058u0wa98ytfc9fd6trhe5qfh9ld