From 7b35f91cec5814b29803a7d9fd5517f638761e67 Mon Sep 17 00:00:00 2001
From: Victor Starodub <v.starodub@corp.mail.ru>
Date: Mon, 25 Apr 2016 02:11:43 +0300
Subject: [PATCH] Closes #21: File-unique auxiliary function names.

---
 bootstrap/bootstrap.go |  2 +-
 gen/decoder.go         |  2 +-
 gen/encoder.go         |  2 +-
 gen/generator.go       | 21 ++++++++++++++++-----
 4 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/bootstrap/bootstrap.go b/bootstrap/bootstrap.go
index d7cd30b..e9a1d21 100644
--- a/bootstrap/bootstrap.go
+++ b/bootstrap/bootstrap.go
@@ -95,7 +95,7 @@ func (g *Generator) writeMain() (path string, err error) {
 	fmt.Fprintln(f, ")")
 	fmt.Fprintln(f)
 	fmt.Fprintln(f, "func main() {")
-	fmt.Fprintln(f, "  g := gen.NewGenerator()")
+	fmt.Fprintf(f, "  g := gen.NewGenerator(%q)\n", filepath.Base(g.OutName))
 	fmt.Fprintf(f, "  g.SetPkg(%q, %q)\n", g.PkgName, g.PkgPath)
 	if g.BuildTags != "" {
 		fmt.Fprintf(f, "  g.SetBuildTags(%q)\n", g.BuildTags)
diff --git a/gen/decoder.go b/gen/decoder.go
index 09c6e89..852caa7 100644
--- a/gen/decoder.go
+++ b/gen/decoder.go
@@ -14,7 +14,7 @@ import (
 const minSliceBytes = 64
 
 func (g *Generator) getStructDecoderName(t reflect.Type) string {
-	return g.functionName("easyjson_decode_", t)
+	return g.functionName("decode_", t)
 }
 
 var primitiveDecoders = map[reflect.Kind]string{
diff --git a/gen/encoder.go b/gen/encoder.go
index 026958b..dfe21f0 100644
--- a/gen/encoder.go
+++ b/gen/encoder.go
@@ -11,7 +11,7 @@ import (
 )
 
 func (g *Generator) getStructEncoderName(t reflect.Type) string {
-	return g.functionName("easyjson_encode_", t)
+	return g.functionName("encode_", t)
 }
 
 var primitiveEncoders = map[reflect.Kind]string{
diff --git a/gen/generator.go b/gen/generator.go
index 5c3362f..07e19fc 100644
--- a/gen/generator.go
+++ b/gen/generator.go
@@ -3,6 +3,7 @@ package gen
 import (
 	"bytes"
 	"fmt"
+	"hash/fnv"
 	"io"
 	"path"
 	"reflect"
@@ -23,9 +24,10 @@ type FieldNamer interface {
 type Generator struct {
 	out *bytes.Buffer
 
-	pkgName   string
-	pkgPath   string
-	buildTags string
+	pkgName    string
+	pkgPath    string
+	buildTags  string
+	funcPrefix string
 
 	varCounter int
 
@@ -51,8 +53,8 @@ type Generator struct {
 }
 
 // NewGenerator initializes and returns a Generator.
-func NewGenerator() *Generator {
-	return &Generator{
+func NewGenerator(filename string) *Generator {
+	ret := &Generator{
 		imports: map[string]string{
 			pkgWriter:       "jwriter",
 			pkgLexer:        "jlexer",
@@ -63,6 +65,14 @@ func NewGenerator() *Generator {
 		typesSeen:     make(map[reflect.Type]bool),
 		functionNames: make(map[string]reflect.Type),
 	}
+
+	// Use a file-unique prefix on all auxiliary functions to avoid
+	// name clashes.
+	hash := fnv.New32()
+	hash.Write([]byte(filename))
+	ret.funcPrefix = fmt.Sprintf("easyjson_%x_", hash.Sum32())
+
+	return ret
 }
 
 // SetPkg sets the name and path of output package.
@@ -257,6 +267,7 @@ func safeName(t reflect.Type) string {
 //
 // Method is used to track encoder/decoder names for the type.
 func (g *Generator) functionName(prefix string, t reflect.Type) string {
+	prefix = g.funcPrefix + prefix
 	name := prefix + safeName(t)
 
 	// Most of the names will be unique, try a shortcut first.