compiler: allow to split main package across multiple files

cli/smartcontract/smart_contract.go

@@ -1,7 +1,6 @@
 package smartcontract
 
 import (
-	"bytes"
 	"encoding/hex"
 	"encoding/json"
 	"errors"
@@ -563,12 +562,10 @@ func inspect(ctx *cli.Context) error {
 	if len(in) == 0 {
 		return cli.NewExitError(errNoInput, 1)
 	}
-	b, err := ioutil.ReadFile(in)
-	if err != nil {
-		return cli.NewExitError(err, 1)
-	}
+	var b []byte
+	var err error
 	if compile {
-		b, err = compiler.Compile(in, bytes.NewReader(b))
+		b, err = compiler.Compile(in, nil)
 		if err != nil {
 			return cli.NewExitError(fmt.Errorf("failed to compile: %w", err), 1)
 		}

pkg/compiler/compiler.go

@@ -1,8 +1,8 @@
 package compiler
 
 import (
-	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"go/ast"
 	"go/parser"
@@ -10,6 +10,7 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+	"path"
 	"strings"
 
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
@@ -85,11 +86,32 @@ func (c *codegen) fillImportMap(f *ast.File, pkg *types.Package) {
 
 func getBuildInfo(name string, src interface{}) (*buildInfo, error) {
 	conf := loader.Config{ParserMode: parser.ParseComments}
+	if src != nil {
 		f, err := conf.ParseFile(name, src)
 		if err != nil {
 			return nil, err
 		}
 		conf.CreateFromFiles("", f)
+	} else {
+		var names []string
+		if strings.HasSuffix(name, ".go") {
+			names = append(names, name)
+		} else {
+			ds, err := ioutil.ReadDir(name)
+			if err != nil {
+				return nil, fmt.Errorf("'%s' is neither Go source nor a directory", name)
+			}
+			for i := range ds {
+				if !ds[i].IsDir() && strings.HasSuffix(ds[i].Name(), ".go") {
+					names = append(names, path.Join(name, ds[i].Name()))
+				}
+			}
+		}
+		if len(names) == 0 {
+			return nil, errors.New("no files provided")
+		}
+		conf.CreateFromFilenames("", names...)
+	}
 
 	prog, err := conf.Load()
 	if err != nil {
@@ -97,12 +119,14 @@ func getBuildInfo(name string, src interface{}) (*buildInfo, error) {
 	}
 
 	return &buildInfo{
-		initialPackage: f.Name.Name,
+		initialPackage: prog.InitialPackages()[0].Pkg.Name(),
 		program:        prog,
 	}, nil
 }
 
 // Compile compiles a Go program into bytecode that can run on the NEO virtual machine.
+// If `r != nil`, `name` is interpreted as a filename, and `r` as file contents.
+// Otherwise `name` is either file name or name of the directory containing source files.
 func Compile(name string, r io.Reader) ([]byte, error) {
 	buf, _, err := CompileWithDebugInfo(name, r)
 	if err != nil {
@@ -123,21 +147,18 @@ func CompileWithDebugInfo(name string, r io.Reader) ([]byte, *DebugInfo, error)
 
 // CompileAndSave will compile and save the file to disk in the NEF format.
 func CompileAndSave(src string, o *Options) ([]byte, error) {
-	if !strings.HasSuffix(src, ".go") {
-		return nil, fmt.Errorf("%s is not a Go file", src)
-	}
 	o.Outfile = strings.TrimSuffix(o.Outfile, fmt.Sprintf(".%s", fileExt))
 	if len(o.Outfile) == 0 {
+		if strings.HasSuffix(src, ".go") {
 			o.Outfile = strings.TrimSuffix(src, ".go")
+		} else {
+			o.Outfile = "out"
+		}
 	}
 	if len(o.Ext) == 0 {
 		o.Ext = fileExt
 	}
-	b, err := ioutil.ReadFile(src)
-	if err != nil {
-		return nil, err
-	}
-	b, di, err := CompileWithDebugInfo(src, bytes.NewReader(b))
+	b, di, err := CompileWithDebugInfo(src, nil)
 	if err != nil {
 		return nil, fmt.Errorf("error while trying to compile smart contract file: %w", err)
 	}

pkg/compiler/compiler_test.go

@@ -24,6 +24,20 @@ func TestCompiler(t *testing.T) {
 	// CompileAndSave use config.Version for proper .nef generation.
 	config.Version = "0.90.0-test"
 	testCases := []compilerTestCase{
+		{
+			name: "TestCompileDirectory",
+			function: func(t *testing.T) {
+				const multiMainDir = "testdata/multi"
+				_, di, err := compiler.CompileWithDebugInfo(multiMainDir, nil)
+				require.NoError(t, err)
+				m := map[string]bool{}
+				for i := range di.Methods {
+					m[di.Methods[i].Name.Name] = true
+				}
+				require.Contains(t, m, "Func1")
+				require.Contains(t, m, "Func2")
+			},
+		},
 		{
 			name: "TestCompile",
 			function: func(t *testing.T) {
@@ -73,10 +87,6 @@ func filterFilename(infos []os.FileInfo) string {
 }
 
 func compileFile(src string) error {
-	file, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	_, err = compiler.Compile("foo.go", file)
+	_, err := compiler.Compile(src, nil)
 	return err
 }

pkg/compiler/testdata/multi/file1.go

@@ -3,3 +3,7 @@ package multi
 var SomeVar12 = 12
 
 const SomeConst = 42
+
+func Func1() bool {
+    return true
+}

pkg/compiler/testdata/multi/file2.go

@@ -5,3 +5,7 @@ var SomeVar30 = 30
 func Sum() int {
 	return SomeVar12 + SomeVar30
 }
+
+func Func2() bool {
+    return false
+}

pkg/vm/cli/cli.go

@@ -6,7 +6,6 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"math/big"
 	"os"
 	"strconv"
@@ -306,12 +305,7 @@ func handleLoadGo(c *ishell.Context) {
 		c.Err(errors.New("missing parameter <file>"))
 		return
 	}
-	fb, err := ioutil.ReadFile(c.Args[0])
-	if err != nil {
-		c.Err(err)
-		return
-	}
-	b, err := compiler.Compile(c.Args[0], bytes.NewReader(fb))
+	b, err := compiler.Compile(c.Args[0], nil)
 	if err != nil {
 		c.Err(err)
 		return