From 5b138fbddafde827b15696b275e26107220ccaf6 Mon Sep 17 00:00:00 2001
From: Vishal Raut <vishal.raut@pdgc.com>
Date: Mon, 6 Dec 2021 12:33:37 +0530
Subject: [PATCH] Bugfix: Skip reading same file multiple times

Also merge types from schemas read from multiple files
---
 xsd/parse.go     |  9 ++++++++-
 xsdgen/cli.go    |  9 ++++++++-
 xsdgen/config.go | 11 +++++++----
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/xsd/parse.go b/xsd/parse.go
index 0e1ac4f..938c1de 100644
--- a/xsd/parse.go
+++ b/xsd/parse.go
@@ -150,7 +150,14 @@ func Parse(docs ...[]byte) ([]Schema, error) {
 		if err := s.parse(root); err != nil {
 			return nil, err
 		}
-		parsed[tns] = s
+		// schema already exists, so merge types with new ones
+		if ps, ok := parsed[tns]; ok {
+			for name, newType := range s.Types {
+				ps.Types[name] = newType
+			}
+		} else {
+			parsed[tns] = s
+		}
 	}
 
 	for _, s := range parsed {
diff --git a/xsdgen/cli.go b/xsdgen/cli.go
index 0274086..6474b0f 100644
--- a/xsdgen/cli.go
+++ b/xsdgen/cli.go
@@ -54,6 +54,7 @@ func (cfg *Config) GenCode(data ...[]byte) (*Code, error) {
 // GenAST creates an *ast.File containing type declarations and
 // associated methods based on a set of XML schema.
 func (cfg *Config) GenAST(files ...string) (*ast.File, error) {
+	cfg.filesRead = make(map[string]bool)
 	data, err := cfg.readFiles(files...)
 	code, err := cfg.GenCode(data...)
 	if err != nil {
@@ -62,14 +63,20 @@ func (cfg *Config) GenAST(files ...string) (*ast.File, error) {
 	return code.GenAST()
 }
 
-func (cfg *Config) readFiles(files ...string) ([][]byte,error) {
+func (cfg *Config) readFiles(files ...string) ([][]byte, error) {
 	data := make([][]byte, 0, len(files))
 	for _, filename := range files {
+		if _, ok := cfg.filesRead[filename]; ok {
+			// skip reading the file again
+			continue
+		}
+
 		b, err := ioutil.ReadFile(filename)
 		if err != nil {
 			return nil, err
 		}
 		cfg.debugf("read %s", filename)
+		cfg.filesRead[filename] = true
 		if cfg.followImports {
 			importedRefs, err := xsd.Imports(b)
 			if err != nil {
diff --git a/xsdgen/config.go b/xsdgen/config.go
index 5a1903f..984b89f 100644
--- a/xsdgen/config.go
+++ b/xsdgen/config.go
@@ -16,10 +16,10 @@ import (
 // A Config holds user-defined overrides and filters that are used when
 // generating Go source code from an xsd document.
 type Config struct {
-	logger          Logger
-	loglevel        int
-	namespaces      []string
-	pkgname         string
+	logger     Logger
+	loglevel   int
+	namespaces []string
+	pkgname    string
 	// load xsd imports recursively into memory before parsing
 	followImports   bool
 	preprocessType  typeTransform
@@ -42,6 +42,9 @@ type Config struct {
 	// if populated, only types that are true in this map
 	// will be selected.
 	allowTypes map[xml.Name]bool
+
+	// keep track of files that are read already to avoid reading it again
+	filesRead map[string]bool
 }
 
 type typeTransform func(xsd.Schema, xsd.Type) xsd.Type