Merge pull request #197 from ethereum/go-txcontext

go: Combine tx context into TxContext struct

appveyor.yml

@@ -47,6 +47,8 @@ build_script:
       copy lib/loader/loader.c bindings/go/evmc
 
       go build ./bindings/go/evmc
+      go generate ./bindings/go/evmc
+      go test -v ./bindings/go/evmc
     }
 
 after_build:

bindings/go/evmc/.gitignore

@@ -0,0 +1 @@
+*.so

bindings/go/evmc/evmc.go

@@ -1,6 +1,6 @@
 // EVMC: Ethereum Client-VM Connector API.
-// Copyright 2018 The EVMC Authors.
+// Copyright 2019 The EVMC Authors.
-// Licensed under the Apache License, Version 2.0. See the LICENSE file.
+// Licensed under the Apache License, Version 2.0.
 
 package evmc
 

bindings/go/evmc/evmc_test.go

@@ -1,24 +1,49 @@
 // EVMC: Ethereum Client-VM Connector API.
-// Copyright 2018 The EVMC Authors.
+// Copyright 2019 The EVMC Authors.
-// Licensed under the Apache License, Version 2.0. See the LICENSE file.
+// Licensed under the Apache License, Version 2.0.
+
+//go:generate gcc -shared ../../../examples/example_vm.c -I../../../include -o example_vm.so
 
 package evmc
 
 import (
-	"os"
+	"bytes"
 	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
 )
 
+var modulePath = "./example_vm.so"
+
 func TestLoad(t *testing.T) {
-	i, err := Load(os.Getenv("EVMC_PATH"))
+	i, err := Load(modulePath)
 	if err != nil {
 		t.Fatal(err.Error())
 	}
 	defer i.Destroy()
-	if i.Name() != "interpreter" {
+	if i.Name() != "example_vm" {
-		t.Fatal("name is not 'interpreter'")
+		t.Fatalf("name is %s", i.Name())
 	}
-	if i.Version()[0] != '1' {
+	if i.Version()[0] < '0' || i.Version()[0] > '9' {
-		t.Fatalf("version is %s", i.Version())
+		t.Fatalf("version number is weird: %s", i.Version())
+	}
+}
+
+func TestExecute(t *testing.T) {
+	vm, _ := Load(modulePath)
+	defer vm.Destroy()
+
+	addr := common.Address{}
+	h := common.Hash{}
+	output, gasLeft, err := vm.Execute(nil, Byzantium, Call, false, 1, 999, addr, addr, nil, h, nil, h)
+
+	if bytes.Compare(output, []byte("Welcome to Byzantium!")) != 0 {
+		t.Errorf("execution unexpected output: %s", output)
+	}
+	if gasLeft != 99 {
+		t.Error("execution gas left is incorrect")
+	}
+	if err != Failure {
+		t.Error("execution returned unexpected error")
 	}
 }

bindings/go/evmc/host.go

@@ -1,6 +1,6 @@
 // EVMC: Ethereum Client-VM Connector API.
-// Copyright 2018 The EVMC Authors.
+// Copyright 2019 The EVMC Authors.
-// Licensed under the Apache License, Version 2.0. See the LICENSE file.
+// Licensed under the Apache License, Version 2.0.
 
 package evmc
 
@@ -69,6 +69,17 @@ func goByteSlice(data *C.uint8_t, size C.size_t) []byte {
 	return (*[1 << 30]byte)(unsafe.Pointer(data))[:size:size]
 }
 
+// TxContext contains information about current transaction and block.
+type TxContext struct {
+	GasPrice   common.Hash
+	Origin     common.Address
+	Coinbase   common.Address
+	Number     int64
+	Timestamp  int64
+	GasLimit   int64
+	Difficulty common.Hash
+}
+
 type HostContext interface {
 	AccountExists(addr common.Address) bool
 	GetStorage(addr common.Address, key common.Hash) common.Hash
@@ -78,8 +89,7 @@ type HostContext interface {
 	GetCodeHash(addr common.Address) common.Hash
 	GetCode(addr common.Address) []byte
 	Selfdestruct(addr common.Address, beneficiary common.Address)
-	GetTxContext() (gasPrice common.Hash, origin common.Address, coinbase common.Address, number int64, timestamp int64,
+	GetTxContext() TxContext
-		gasLimit int64, difficulty common.Hash)
 	GetBlockHash(number int64) common.Hash
 	EmitLog(addr common.Address, topics []common.Hash, data []byte)
 	Call(kind CallKind,
@@ -162,16 +172,16 @@ func getTxContext(pCtx unsafe.Pointer) C.struct_evmc_tx_context {
 	idx := int((*C.struct_extended_context)(pCtx).index)
 	ctx := getHostContext(idx)
 
-	gasPrice, origin, coinbase, number, timestamp, gasLimit, difficulty := ctx.GetTxContext()
+	txContext := ctx.GetTxContext()
 
 	return C.struct_evmc_tx_context{
-		evmcBytes32(gasPrice),
+		evmcBytes32(txContext.GasPrice),
-		evmcAddress(origin),
+		evmcAddress(txContext.Origin),
-		evmcAddress(coinbase),
+		evmcAddress(txContext.Coinbase),
-		C.int64_t(number),
+		C.int64_t(txContext.Number),
-		C.int64_t(timestamp),
+		C.int64_t(txContext.Timestamp),
-		C.int64_t(gasLimit),
+		C.int64_t(txContext.GasLimit),
-		evmcBytes32(difficulty),
+		evmcBytes32(txContext.Difficulty),
 	}
 }
 

bindings/go/evmc/host_test.go

@@ -0,0 +1,90 @@
+// EVMC: Ethereum Client-VM Connector API.
+// Copyright 2019 The EVMC Authors.
+// Licensed under the Apache License, Version 2.0.
+
+package evmc
+
+import (
+	"bytes"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+type testHostContext struct{}
+
+func (host *testHostContext) AccountExists(addr common.Address) bool {
+	return false
+}
+
+func (host *testHostContext) GetStorage(addr common.Address, key common.Hash) common.Hash {
+	return common.Hash{}
+}
+
+func (host *testHostContext) SetStorage(addr common.Address, key common.Hash, value common.Hash) (status StorageStatus) {
+	return StorageUnchanged
+}
+
+func (host *testHostContext) GetBalance(addr common.Address) common.Hash {
+	return common.Hash{}
+}
+
+func (host *testHostContext) GetCodeSize(addr common.Address) int {
+	return 0
+}
+
+func (host *testHostContext) GetCodeHash(addr common.Address) common.Hash {
+	return common.Hash{}
+}
+
+func (host *testHostContext) GetCode(addr common.Address) []byte {
+	return nil
+}
+
+func (host *testHostContext) Selfdestruct(addr common.Address, beneficiary common.Address) {
+}
+
+func (host *testHostContext) GetTxContext() TxContext {
+	txContext := TxContext{}
+	txContext.Number = 42
+	return txContext
+}
+
+func (host *testHostContext) GetBlockHash(number int64) common.Hash {
+	return common.Hash{}
+}
+
+func (host *testHostContext) EmitLog(addr common.Address, topics []common.Hash, data []byte) {
+}
+
+func (host *testHostContext) Call(kind CallKind,
+	destination common.Address, sender common.Address, value *big.Int, input []byte, gas int64, depth int,
+	static bool, salt *big.Int) (output []byte, gasLeft int64, createAddr common.Address, err error) {
+	return nil, gas, common.Address{}, nil
+}
+
+func TestGetTxContext(t *testing.T) {
+	vm, _ := Load(modulePath)
+	defer vm.Destroy()
+
+	host := &testHostContext{}
+	code := []byte("\x43\x60\x00\x52\x59\x60\x00\xf3")
+
+	addr := common.Address{}
+	h := common.Hash{}
+	output, gasLeft, err := vm.Execute(host, Byzantium, Call, false, 1, 100, addr, addr, nil, h, code, h)
+
+	if len(output) != 20 {
+		t.Errorf("unexpected output size: %d", len(output))
+	}
+	if bytes.Compare(output[0:3], []byte("42\x00")) != 0 {
+		t.Errorf("execution unexpected output: %s", output)
+	}
+	if gasLeft != 50 {
+		t.Errorf("execution gas left is incorrect: %x", gasLeft)
+	}
+	if err != nil {
+		t.Error("execution returned unexpected error")
+	}
+}

circle.yml

@@ -147,6 +147,8 @@ jobs:
             go get -v github.com/ethereum/go-ethereum/common
             go build -v ./bindings/go/evmc
             go vet -v ./bindings/go/evmc
+            go generate -v ./bindings/go/evmc
+            go test -v ./bindings/go/evmc
 
   bindings-go-1.9:
     docker:

examples/example_vm.c

@@ -91,6 +91,7 @@ static struct evmc_result execute(struct evmc_instance* instance,
         ret.output_data = (const uint8_t*)error;
         ret.output_size = strlen(error);
         ret.status_code = EVMC_FAILURE;
+        ret.gas_left = msg->gas / 10;
         ret.release = NULL;  // We don't need to release the constant messages.
         return ret;
     }
@@ -106,7 +107,10 @@ static struct evmc_result execute(struct evmc_instance* instance,
     // Assembly: `{ sstore(0, add(sload(0), 1)) }`
     const char counter[] = "\x60\x01\x60\x00\x54\x01\x60\x00\x55";
 
-    if (code_size == strlen(return_address) &&
+    // Assembly: `{ mstore(0, number()) return(0, msize()) }`
+    const char return_block_number[] = "\x43\x60\x00\x52\x59\x60\x00\xf3";
+
+    if (code_size == (sizeof(return_address) - 1) &&
         strncmp((const char*)code, return_address, code_size) == 0)
     {
         static const size_t address_size = sizeof(msg->destination);
@@ -124,7 +128,8 @@ static struct evmc_result execute(struct evmc_instance* instance,
         ret.release = &free_result_output_data;
         return ret;
     }
-    else if (code_size == strlen(counter) && strncmp((const char*)code, counter, code_size) == 0)
+    else if (code_size == (sizeof(counter) - 1) &&
+             strncmp((const char*)code, counter, code_size) == 0)
     {
         const evmc_bytes32 key = {{0}};
         evmc_bytes32 value = context->host->get_storage(context, &msg->destination, &key);
@@ -133,6 +138,21 @@ static struct evmc_result execute(struct evmc_instance* instance,
         ret.status_code = EVMC_SUCCESS;
         return ret;
     }
+    else if (code_size == (sizeof(return_block_number) - 1) &&
+             strncmp((const char*)code, return_block_number, code_size) == 0)
+    {
+        const struct evmc_tx_context tx_context = context->host->get_tx_context(context);
+        const size_t output_size = 20;
+
+        uint8_t* output_data = (uint8_t*)calloc(1, output_size);
+        snprintf((char*)output_data, output_size, "%u", (unsigned)tx_context.block_number);
+        ret.status_code = EVMC_SUCCESS;
+        ret.gas_left = msg->gas / 2;
+        ret.output_data = output_data;
+        ret.output_size = output_size;
+        ret.release = &free_result_output_data;
+        return ret;
+    }
 
     ret.status_code = EVMC_FAILURE;
     ret.gas_left = 0;