internal/ini: adding ini parser

aws/session/shared_config.go

@@ -2,11 +2,11 @@ package session
 
 import (
 	"fmt"
-	"io/ioutil"
 
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/aws/credentials"
-	"github.com/go-ini/ini"
+
+	"github.com/aws/aws-sdk-go/internal/ini"
 )
 
 const (
@@ -66,7 +66,7 @@ type sharedConfig struct {
 
 type sharedConfigFile struct {
 	Filename string
-	IniData  *ini.File
+	IniData  ini.Sections
 }
 
 // loadSharedConfig retrieves the configuration from the list of files
@@ -107,19 +107,16 @@ func loadSharedConfigIniFiles(filenames []string) ([]sharedConfigFile, error) {
 	files := make([]sharedConfigFile, 0, len(filenames))
 
 	for _, filename := range filenames {
-		b, err := ioutil.ReadFile(filename)
-		if err != nil {
+		sections, err := ini.OpenFile(filename)
+		if aerr, ok := err.(awserr.Error); ok && aerr.Code() == ini.ErrCodeUnableToReadFile {
 			// Skip files which can't be opened and read for whatever reason
 			continue
-		}
-
-		f, err := ini.Load(b)
-		if err != nil {
+		} else if err != nil {
 			return nil, SharedConfigLoadError{Filename: filename, Err: err}
 		}
 
 		files = append(files, sharedConfigFile{
-			Filename: filename, IniData: f,
+			Filename: filename, IniData: sections,
 		})
 	}
 
@@ -180,45 +177,45 @@ func (cfg *sharedConfig) setFromIniFiles(profile string, files []sharedConfigFil
 // if a config file only includes aws_access_key_id but no aws_secret_access_key
 // the aws_access_key_id will be ignored.
 func (cfg *sharedConfig) setFromIniFile(profile string, file sharedConfigFile) error {
-	section, err := file.IniData.GetSection(profile)
-	if err != nil {
+	section, ok := file.IniData.GetSection(profile)
+	if !ok {
 		// Fallback to to alternate profile name: profile <name>
-		section, err = file.IniData.GetSection(fmt.Sprintf("profile %s", profile))
-		if err != nil {
-			return SharedConfigProfileNotExistsError{Profile: profile, Err: err}
+		section, ok = file.IniData.GetSection(fmt.Sprintf("profile %s", profile))
+		if !ok {
+			return SharedConfigProfileNotExistsError{Profile: profile, Err: nil}
 		}
 	}
 
 	// Shared Credentials
-	akid := section.Key(accessKeyIDKey).String()
-	secret := section.Key(secretAccessKey).String()
+	akid := section.String(accessKeyIDKey)
+	secret := section.String(secretAccessKey)
 	if len(akid) > 0 && len(secret) > 0 {
 		cfg.Creds = credentials.Value{
 			AccessKeyID:     akid,
 			SecretAccessKey: secret,
-			SessionToken:    section.Key(sessionTokenKey).String(),
+			SessionToken:    section.String(sessionTokenKey),
 			ProviderName:    fmt.Sprintf("SharedConfigCredentials: %s", file.Filename),
 		}
 	}
 
 	// Assume Role
-	roleArn := section.Key(roleArnKey).String()
-	srcProfile := section.Key(sourceProfileKey).String()
-	credentialSource := section.Key(credentialSourceKey).String()
+	roleArn := section.String(roleArnKey)
+	srcProfile := section.String(sourceProfileKey)
+	credentialSource := section.String(credentialSourceKey)
 	hasSource := len(srcProfile) > 0 || len(credentialSource) > 0
 	if len(roleArn) > 0 && hasSource {
 		cfg.AssumeRole = assumeRoleConfig{
 			RoleARN:          roleArn,
 			SourceProfile:    srcProfile,
 			CredentialSource: credentialSource,
-			ExternalID:       section.Key(externalIDKey).String(),
-			MFASerial:        section.Key(mfaSerialKey).String(),
-			RoleSessionName:  section.Key(roleSessionNameKey).String(),
+			ExternalID:       section.String(externalIDKey),
+			MFASerial:        section.String(mfaSerialKey),
+			RoleSessionName:  section.String(roleSessionNameKey),
 		}
 	}
 
 	// Region
-	if v := section.Key(regionKey).String(); len(v) > 0 {
+	if v := section.String(regionKey); len(v) > 0 {
 		cfg.Region = v
 	}
 

aws/session/shared_config_test.go

@@ -6,7 +6,7 @@ import (
 	"testing"
 
 	"github.com/aws/aws-sdk-go/aws/credentials"
-	"github.com/go-ini/ini"
+	"github.com/aws/aws-sdk-go/internal/ini"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -140,7 +140,7 @@ func TestLoadSharedConfig(t *testing.T) {
 
 func TestLoadSharedConfigFromFile(t *testing.T) {
 	filename := testConfigFilename
-	f, err := ini.Load(filename)
+	f, err := ini.OpenFile(filename)
 	if err != nil {
 		t.Fatalf("failed to load test config file, %s, %v", filename, err)
 	}

internal/ini/ast.go

@@ -0,0 +1,120 @@
+package ini
+
+// ASTKind represents different states in the parse table
+// and the type of AST that is being constructed
+type ASTKind int
+
+// ASTKind* is used in the parse table to transition between
+// the different states
+const (
+	ASTKindNone = ASTKind(iota)
+	ASTKindStart
+	ASTKindExpr
+	ASTKindEqualExpr
+	ASTKindStatement
+	ASTKindSkipStatement
+	ASTKindExprStatement
+	ASTKindSectionStatement
+	ASTKindNestedSectionStatement
+	ASTKindCompletedNestedSectionStatement
+	ASTKindCommentStatement
+	ASTKindCompletedSectionStatement
+)
+
+func (k ASTKind) String() string {
+	switch k {
+	case ASTKindNone:
+		return "none"
+	case ASTKindStart:
+		return "start"
+	case ASTKindExpr:
+		return "expr"
+	case ASTKindStatement:
+		return "stmt"
+	case ASTKindSectionStatement:
+		return "section_stmt"
+	case ASTKindExprStatement:
+		return "expr_stmt"
+	case ASTKindCommentStatement:
+		return "comment"
+	case ASTKindNestedSectionStatement:
+		return "nested_section_stmt"
+	case ASTKindCompletedSectionStatement:
+		return "completed_stmt"
+	case ASTKindSkipStatement:
+		return "skip"
+	default:
+		return ""
+	}
+}
+
+// AST interface allows us to determine what kind of node we
+// are on and casting may not need to be necessary.
+//
+// The root is always the first node in Children
+type AST struct {
+	Kind      ASTKind
+	Root      Token
+	RootToken bool
+	Children  []AST
+}
+
+func newAST(kind ASTKind, root AST, children ...AST) AST {
+	return AST{
+		Kind:     kind,
+		Children: append([]AST{root}, children...),
+	}
+}
+
+func newASTWithRootToken(kind ASTKind, root Token, children ...AST) AST {
+	return AST{
+		Kind:      kind,
+		Root:      root,
+		RootToken: true,
+		Children:  children,
+	}
+}
+
+// AppendChild will append to the list of children an AST has.
+func (a *AST) AppendChild(child AST) {
+	a.Children = append(a.Children, child)
+}
+
+// GetRoot will return the root AST which can be the first entry
+// in the children list or a token.
+func (a *AST) GetRoot() AST {
+	if a.RootToken {
+		return *a
+	}
+
+	if len(a.Children) == 0 {
+		return AST{}
+	}
+
+	return a.Children[0]
+}
+
+// GetChildren will return the current AST's list of children
+func (a *AST) GetChildren() []AST {
+	if len(a.Children) == 0 {
+		return []AST{}
+	}
+
+	if a.RootToken {
+		return a.Children
+	}
+
+	return a.Children[1:]
+}
+
+// SetChildren will set and override all children of the AST.
+func (a *AST) SetChildren(children []AST) {
+	if a.RootToken {
+		a.Children = children
+	} else {
+		a.Children = append(a.Children[:1], children...)
+	}
+}
+
+// Start is used to indicate the starting state of the parse table.
+var Start = newAST(ASTKindStart, AST{})

internal/ini/bench_test.go

@@ -0,0 +1,40 @@
+package ini
+
+import (
+	oldini "github.com/go-ini/ini"
+	"testing"
+)
+
+const (
+	section = `[default]
+region = us-west-2
+credential_source = Ec2InstanceMetadata
+s3 =
+	foo=bar
+	bar=baz
+output = json
+
+[assumerole]
+output = json
+region = us-west-2
+`
+)
+
+func BenchmarkINIParser(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		ParseBytes([]byte(section))
+	}
+}
+
+func BenchmarkGoINIParser(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		oldini.Load([]byte(section))
+	}
+}
+
+func BenchmarkTokenize(b *testing.B) {
+	lexer := iniLexer{}
+	for i := 0; i < b.N; i++ {
+		lexer.tokenize([]byte(section))
+	}
+}

internal/ini/comma_token.go

@@ -0,0 +1,11 @@
+package ini
+
+var commaRunes = []rune(",")
+
+func isComma(b rune) bool {
+	return b == ','
+}
+
+func newCommaToken() Token {
+	return newToken(TokenComma, commaRunes, NoneType)
+}

internal/ini/comment_token.go

@@ -0,0 +1,39 @@
+package ini
+
+// isComment will return whether or not the next byte(s) is a
+// comment.
+func isComment(b []rune) bool {
+	if len(b) == 0 {
+		return false
+	}
+
+	switch b[0] {
+	case ';':
+		return true
+	case '#':
+		return true
+	case '/':
+		if len(b) > 1 {
+			return b[1] == '/'
+		}
+	}
+
+	return false
+}
+
+// newCommentToken will create a comment token and
+// return how many bytes were read.
+func newCommentToken(b []rune) (Token, int, error) {
+	i := 0
+	for ; i < len(b); i++ {
+		if b[i] == '\n' {
+			break
+		}
+
+		if len(b)-i > 2 && b[i] == '\r' && b[i+1] == '\n' {
+			break
+		}
+	}
+
+	return newToken(TokenComment, b[:i], NoneType), i, nil
+}

internal/ini/doc.go

@@ -0,0 +1,30 @@
+// Package ini is an LL(1) parser for configuration files.
+//
+//	Example:
+//	sections, err := ini.OpenFile("/path/to/file")
+//	if err != nil {
+//		panic(err)
+//	}
+//
+//	profile := "foo"
+//	section, ok := sections.GetSection(profile)
+//	if !ok {
+//		fmt.Printf("section %q could not be found", profile)
+//	}
+//
+// Below is the BNF that describes this parser
+//	Grammar:
+//	stmt -> value stmt'
+//	stmt' -> epsilon | op stmt
+//	value -> number | string | boolean | quoted_string
+//
+//	section -> [ section'
+//	section' -> value section_close
+//	section_close -> ]
+//
+//	SkipState will skip (NL WS)+
+//
+//	comment -> # comment' | ; comment' | / comment_slash
+//	comment_slash -> / comment'
+//	comment' -> epsilon | value
+package ini

internal/ini/empty_token.go

@@ -0,0 +1,4 @@
+package ini
+
+// emptyToken is used to satisfy the Token interface
+var emptyToken = newToken(TokenNone, []rune{}, NoneType)