parser: Dummp Replace ast.Node on REPLACE token

To implement the Replace operation the token REPLACE has to be understood by the parser and construct the proper ast.Node. Signed-off-by: Quique Llorente <[email protected]>
nmstate · Dec 2, 2021 · 060fe1f · 060fe1f
1 parent f4ed96a
commit 060fe1f
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Showing 4 changed files with 168 additions and 6 deletions.
diff --git a/nmpolicy/internal/ast/types.go b/nmpolicy/internal/ast/types.go
@@ -31,6 +31,7 @@ type Terminal struct {
 type Node struct {
 	Meta
 	EqFilter *TernaryOperator  `json:"eqfilter,omitempty"`
+	Replace  *TernaryOperator  `json:"replace,omitempty"`
 	Path     *VariadicOperator `json:"path,omitempty"`
 	Terminal
 }
diff --git a/nmpolicy/internal/parser/errors.go b/nmpolicy/internal/parser/errors.go
@@ -65,6 +65,13 @@ func invalidEqualityFilterError(msg string) *parserError {
 	}
 }
 
+func invalidReplaceError(msg string) *parserError {
+	return &parserError{
+		prefix: "invalid replace",
+		msg:    msg,
+	}
+}
+
 func invalidExpressionError(msg string) *parserError {
 	return &parserError{
 		prefix: "invalid expression",

diff --git a/nmpolicy/internal/parser/parser.go b/nmpolicy/internal/parser/parser.go
@@ -71,6 +71,10 @@ func (p *parser) parse() (ast.Node, error) {
 			if err := p.parseEqFilter(); err != nil {
 				return ast.Node{}, err
 			}
+		} else if p.currentToken().Type == lexer.REPLACE {
+			if err := p.parseReplace(); err != nil {
+				return ast.Node{}, err
+			}
 		} else {
 			return ast.Node{}, invalidExpressionError(fmt.Sprintf("unexpected token `%+v`", p.currentToken().Literal))
 		}
@@ -165,7 +169,7 @@ func (p *parser) parsePath() error {
 			}
 			path := append(*operator.Path, *p.lastNode)
 			operator.Path = &path
-		} else if p.currentToken().Type != lexer.EOF && p.currentToken().Type != lexer.EQFILTER {
+		} else if p.currentToken().Type != lexer.EOF && p.currentToken().Type != lexer.EQFILTER && p.currentToken().Type != lexer.REPLACE {
 			return invalidPathError("missing dot")
 		} else {
 			// Token has not being consumed let's go back.
@@ -204,9 +208,40 @@ func (p *parser) parseEqFilter() error {
 			return err
 		}
 		operator.EqFilter[2] = *p.lastNode
-	} else if p.currentToken().Type != lexer.EOF {
+	} else if p.currentToken().Type == lexer.EOF {
+		return invalidEqualityFilterError("missing right hand argument")
+	} else {
 		return invalidEqualityFilterError("right hand argument is not a string or identity")
 	}
 	p.lastNode = operator
 	return nil
 }
+
+func (p *parser) parseReplace() error {
+	operator := &ast.Node{
+		Meta:    ast.Meta{Position: p.currentToken().Position},
+		Replace: &ast.TernaryOperator{},
+	}
+	if p.lastNode == nil {
+		return invalidReplaceError("missing left hand argument")
+	}
+	if p.lastNode.Path == nil {
+		return invalidReplaceError("left hand argument is not a path")
+	}
+	operator.Replace[0].Terminal = ast.CurrentStateIdentity()
+	operator.Replace[1] = *p.lastNode
+
+	p.nextToken()
+	if p.currentToken().Type == lexer.STRING {
+		if err := p.parseString(); err != nil {
+			return err
+		}
+		operator.Replace[2] = *p.lastNode
+	} else if p.currentToken().Type == lexer.EOF {
+		return invalidReplaceError("missing right hand argument")
+	} else {
+		return invalidReplaceError("right hand argument is not a string")
+	}
+	p.lastNode = operator
+	return nil
+}
diff --git a/nmpolicy/internal/parser/parser_test.go b/nmpolicy/internal/parser/parser_test.go
@@ -29,19 +29,32 @@ import (
 )
 
 func TestParser(t *testing.T) {
-	testParseFailures(t)
-	testParseSuccess(t)
+	testParsePath(t)
+	testParseEqFilter(t)
+	testParseReplace(t)
+
+	testParseBasicFailures(t)
+	testParsePathFailures(t)
+	testParseEqFilterFailure(t)
+	testParseReplaceFailure(t)
+
 	testParserReuse(t)
 }
 
-func testParseFailures(t *testing.T) {
+func testParseBasicFailures(t *testing.T) {
 	var tests = []test{
 		expectError("invalid expression: unexpected token `.`",
 			fromTokens(
 				dot(),
 				eof(),
 			),
 		),
+	}
+	runTest(t, tests)
+}
+
+func testParsePathFailures(t *testing.T) {
+	var tests = []test{
 		expectError(`invalid path: missing identity or number after dot`,
 			fromTokens(
 				identity("routes"),
@@ -65,6 +78,12 @@ func testParseFailures(t *testing.T) {
 				eof(),
 			),
 		),
+	}
+	runTest(t, tests)
+}
+
+func testParseEqFilterFailure(t *testing.T) {
+	var tests = []test{
 		expectError(`invalid equality filter: missing left hand argument`,
 			fromTokens(
 				eqfilter(),
@@ -80,6 +99,18 @@ func testParseFailures(t *testing.T) {
 				eof(),
 			),
 		),
+		expectError(`invalid equality filter: missing right hand argument`,
+			fromTokens(
+				identity("routes"),
+				dot(),
+				identity("running"),
+				dot(),
+				identity("destination"),
+				eqfilter(),
+				eof(),
+			),
+		),
+
 		expectError(`invalid equality filter: right hand argument is not a string or identity`,
 			fromTokens(
 				identity("routes"),
@@ -96,7 +127,52 @@ func testParseFailures(t *testing.T) {
 	runTest(t, tests)
 }
 
-func testParseSuccess(t *testing.T) {
+func testParseReplaceFailure(t *testing.T) {
+	var tests = []test{
+		expectError(`invalid replace: missing left hand argument`,
+			fromTokens(
+				replace(),
+				str("0.0.0.0/0"),
+				eof(),
+			),
+		),
+		expectError(`invalid replace: left hand argument is not a path`,
+			fromTokens(
+				str("foo"),
+				replace(),
+				str("0.0.0.0/0"),
+				eof(),
+			),
+		),
+		expectError(`invalid replace: missing right hand argument`,
+			fromTokens(
+				identity("routes"),
+				dot(),
+				identity("running"),
+				dot(),
+				identity("destination"),
+				replace(),
+				eof(),
+			),
+		),
+
+		expectError(`invalid replace: right hand argument is not a string`,
+			fromTokens(
+				identity("routes"),
+				dot(),
+				identity("running"),
+				dot(),
+				identity("destination"),
+				replace(),
+				replace(),
+				eof(),
+			),
+		),
+	}
+	runTest(t, tests)
+}
+
+func testParsePath(t *testing.T) {
 	var tests = []test{
 		expectEmptyAST(fromTokens()),
 		expectEmptyAST(fromTokens(eof())),
@@ -118,6 +194,12 @@ path:
 				eof(),
 			),
 		),
+	}
+	runTest(t, tests)
+}
+
+func testParseEqFilter(t *testing.T) {
+	var tests = []test{
 		expectAST(t, `
 pos: 26
 eqfilter: 
@@ -193,6 +275,39 @@ eqfilter:
 	runTest(t, tests)
 }
 
+func testParseReplace(t *testing.T) {
+	var tests = []test{
+		expectAST(t, `
+pos: 33
+replace:
+- pos: 0
+  identity: currentState
+- pos: 0 
+  path: 
+  - pos: 0 
+    identity: routes
+  - pos: 7
+    identity: running
+  - pos: 15
+    identity: next-hop-interface
+- pos: 35
+  string: br1
+`,
+			fromTokens(
+				identity("routes"),
+				dot(),
+				identity("running"),
+				dot(),
+				identity("next-hop-interface"),
+				replace(),
+				str("br1"),
+				eof(),
+			),
+		),
+	}
+	runTest(t, tests)
+}
+
 func testParserReuse(t *testing.T) {
 	p := parser.New()
 	testToRun1 := expectAST(t, `
@@ -333,3 +448,7 @@ func eof() lexer.Token {
 func eqfilter() lexer.Token {
 	return lexer.Token{Type: lexer.EQFILTER, Literal: "=="}
 }
+
+func replace() lexer.Token {
+	return lexer.Token{Type: lexer.REPLACE, Literal: ":="}
+}