refactor(perfdata): split the range parser into many functions
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SHA256:l7PFUUF5TCDsvYeQC9OnTNz08dFY7Fvf4Hv3neIqYpg
4 changed files with 262 additions and 177 deletions
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@ -3,7 +3,6 @@ package perfdata // import nocternity.net/gomonop/pkg/perfdata
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import (
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"fmt"
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"strconv"
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"strings"
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)
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// Performance data range.
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@ -92,121 +91,3 @@ func (r *Range) Contains(value float64) bool {
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return (inStart || inEnd) != r.inside
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}
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// A state of the range parser.
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type rangeParserState int
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const (
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rpsInit rangeParserState = iota // Initial state
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rpsExpectStart // Expect the start of the range
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rpsInStart // Reading the start of the range
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rpsExpectColon // Expect the colon that separates the start and end
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rpsExpectEnd // Expect the end of the range
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rpsInEnd // Reading the end of the range
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)
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// An error emitted by the range parser.
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type rangeParserError struct {
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input string
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position int
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message string
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}
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// parseError creates a new range parser error.
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func parseError(input string, position int, message string) *rangeParserError {
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return &rangeParserError{
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input: input,
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position: position,
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message: message,
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}
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}
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// Error implements the error interface for the range parser error type.
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func (rpe *rangeParserError) Error() string {
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return fmt.Sprintf("in `%s' at position %d: %s", rpe.input, rpe.position, rpe.message)
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}
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// Try to parse a string into a performance data range.
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func ParseRange(input string) (*Range, error) {
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runes := []rune(input)
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index := 0
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state := rpsInit
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parsed := Range{}
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startOfStart := 0
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startOfEnd := 0
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strBuilder := strings.Builder{}
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for index < len(runes) {
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curRune := runes[index]
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switch state {
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case rpsInit:
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if curRune == '@' {
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parsed.inside = true
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index++
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}
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state = rpsExpectStart
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case rpsExpectStart:
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switch curRune {
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case ':':
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parsed.start = "0"
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state = rpsExpectEnd
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case '~':
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state = rpsExpectColon
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default:
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strBuilder.WriteRune(curRune)
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startOfStart = index
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state = rpsInStart
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}
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index++
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case rpsInStart:
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switch curRune {
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case ':':
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parsed.start = strBuilder.String()
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if !valueCheck.MatchString(parsed.start) {
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return nil, parseError(input, startOfStart, "invalid start value")
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}
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strBuilder.Reset()
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state = rpsExpectEnd
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default:
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strBuilder.WriteRune(curRune)
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}
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index++
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case rpsExpectColon:
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switch curRune {
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case ':':
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state = rpsExpectEnd
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index++
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default:
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return nil, parseError(input, index, "expected ':'")
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}
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case rpsExpectEnd:
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startOfEnd = index
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state = rpsInEnd
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case rpsInEnd:
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strBuilder.WriteRune(curRune)
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index++
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}
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}
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if state == rpsInStart {
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// The range was a single value, so that's the upper bound.
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parsed.start = "0"
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state = rpsInEnd
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}
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if state != rpsInEnd {
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return nil, parseError(input, index, "unexpected end of input")
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}
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parsed.end = strBuilder.String()
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if !valueCheck.MatchString(parsed.end) {
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return nil, parseError(input, startOfEnd, "invalid end value")
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}
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return &parsed, nil
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}
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@ -2,11 +2,9 @@ package perfdata // import nocternity.net/gomonop/pkg/perfdata
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import (
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"fmt"
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"strings"
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"testing"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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func TestRangeMaxInvalid(t *testing.T) {
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@ -126,59 +124,3 @@ func TestRangeContains(t *testing.T) {
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})
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}
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}
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func TestRangeParserOk(t *testing.T) {
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type Test struct {
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in string
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out Range
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}
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tests := []Test{
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{in: ":0", out: Range{start: "0", end: "0"}},
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{in: "0:0", out: Range{start: "0", end: "0"}},
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{in: "~:0", out: Range{start: "", end: "0"}},
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{in: ":123", out: Range{start: "0", end: "123"}},
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{in: "0:123", out: Range{start: "0", end: "123"}},
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{in: "~:123", out: Range{start: "", end: "123"}},
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{in: "1", out: Range{start: "0", end: "1"}},
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{in: "@:0", out: Range{start: "0", end: "0", inside: true}},
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{in: "@0:0", out: Range{start: "0", end: "0", inside: true}},
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{in: "@~:0", out: Range{start: "", end: "0", inside: true}},
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{in: "@:123", out: Range{start: "0", end: "123", inside: true}},
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{in: "@0:123", out: Range{start: "0", end: "123", inside: true}},
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{in: "@~:123", out: Range{start: "", end: "123", inside: true}},
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{in: "@1", out: Range{start: "0", end: "1", inside: true}},
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}
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for _, test := range tests {
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result, err := ParseRange(test.in)
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require.NoError(t, err, "Expected no error, got '%v'", err)
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assert.Equal(t, test.out, *result, "Expected '%v', got '%v'", test.out, *result)
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}
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}
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func TestRangeParserError(t *testing.T) {
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type Test struct {
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in string
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errPos int
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}
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tests := []Test{
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{in: "", errPos: 0},
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{in: ":", errPos: 1},
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{in: "x:1", errPos: 0},
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{in: ":~", errPos: 1},
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{in: "@", errPos: 1},
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{in: "@:", errPos: 2},
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{in: "@x:1", errPos: 1},
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{in: "@:~", errPos: 2},
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}
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for _, test := range tests {
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result, err := ParseRange(test.in)
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require.Error(t, err, "Expected error, got '%v'", err)
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assert.Nil(t, result, "Expected nil result, got '%v'", result)
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assert.True(
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t, strings.Contains(err.Error(), fmt.Sprintf("at position %d", test.errPos)),
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"Expected error to contain '%s', got '%s'", fmt.Sprintf("at position %d", test.errPos), err,
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)
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}
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}
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196
pkg/perfdata/rangeparser.go
Normal file
196
pkg/perfdata/rangeparser.go
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@ -0,0 +1,196 @@
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package perfdata // import nocternity.net/gomonop/pkg/perfdata
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import (
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"fmt"
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"strings"
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)
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// A state of the range parser.
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type rangeParserState int
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const (
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rpsInit rangeParserState = iota // Initial state
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rpsExpectStart // Expect the start of the range
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rpsInStart // Reading the start of the range
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rpsExpectColon // Expect the colon that separates the start and end
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rpsExpectEnd // Expect the end of the range
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rpsInEnd // Reading the end of the range
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)
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// An error emitted by the range parser.
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type rangeParserError struct {
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input string
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position int
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message string
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}
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// parseError creates a new range parser error.
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func parseError(input string, position int, message string) *rangeParserError {
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return &rangeParserError{
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input: input,
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position: position,
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message: message,
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}
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}
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// Error implements the error interface for the range parser error type.
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func (rpe *rangeParserError) Error() string {
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return fmt.Sprintf("in `%s' at position %d: %s", rpe.input, rpe.position, rpe.message)
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}
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// The full state of the range parser.
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type rangeParser struct {
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runes []rune // The runes being parsed
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index int // The read position
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state rangeParserState // The FSM state
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startOfValue int // The position of the start of the value being read
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strBuilder strings.Builder // An accumulator for values
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output Range // The output being generated
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}
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// initRangeParser initializes the range parser from the specified input.
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func initRangeParser(input string) *rangeParser {
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return &rangeParser{
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runes: []rune(input),
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state: rpsInit,
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}
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}
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// handleInit handles the parser's rpsInit state. It can accept a '@' or skip
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// to rpsExpectStart.
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func (rp *rangeParser) handleInit(current rune) {
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if current == '@' {
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rp.output.inside = true
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rp.index++
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}
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rp.state = rpsExpectStart
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}
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// handleExpectStart handles the parser's rpsExpectStart state. It may accept
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// a colon, which will move the parser to the rpsExpectEnd state, a '~' which
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// will move it to rpsExpectColon, or any other rune which will cause the
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// accumulation of the "start" value to begin, and the state to be moved to
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// handleInStart.
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func (rp *rangeParser) handleExpectStart(current rune) {
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switch current {
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case ':':
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rp.output.start = "0"
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rp.state = rpsExpectEnd
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rp.index++
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case '~':
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rp.state = rpsExpectColon
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rp.index++
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default:
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rp.startOfValue = rp.index
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rp.state = rpsInStart
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}
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}
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// handleInStart handles the parser's rpsInStart state, which corresponds to the
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// reading of the "start" value. If a colon is found, the value will be written
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// to the range structure and validated, before switching to the rpsExpectEnd
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// state. Otherwise it will simply accumulate runes.
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func (rp *rangeParser) handleInStart(current rune) error {
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switch current {
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case ':':
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rp.output.start = rp.strBuilder.String()
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if !valueCheck.MatchString(rp.output.start) {
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return parseError(string(rp.runes), rp.startOfValue, "invalid start value")
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}
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rp.strBuilder.Reset()
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rp.state = rpsExpectEnd
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default:
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rp.strBuilder.WriteRune(current)
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}
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rp.index++
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return nil
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}
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// handleExpectColon handles the parser's rpsExpectColon state. A colon MUST be
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// read, otherwise an error will be returned. The parser will then switch to the
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// rpsExpectEnd state.
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func (rp *rangeParser) handleExpectColon(current rune) error {
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switch current {
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case ':':
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rp.state = rpsExpectEnd
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rp.index++
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default:
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return parseError(string(rp.runes), rp.index, "expected ':'")
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}
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return nil
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}
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// handleExpectEnd handles the parser's rpsExpectEnd state, which sets the
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// position of the beginning of the "end" value, and jumps to the rpsInEnd
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// state.
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func (rp *rangeParser) handleExpectEnd() {
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rp.startOfValue = rp.index
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rp.state = rpsInEnd
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}
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// handleInEnd handles the parser's rpsInEnd state, which accumulates runes for
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// the "end" value.
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func (rp *rangeParser) handleInEnd(current rune) {
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rp.strBuilder.WriteRune(current)
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rp.index++
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}
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// consumeInput is the parser's state machine.
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func (rp *rangeParser) consumeInput() error {
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for rp.index < len(rp.runes) {
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var err error
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curRune := rp.runes[rp.index]
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switch rp.state {
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case rpsInit:
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rp.handleInit(curRune)
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case rpsExpectStart:
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rp.handleExpectStart(curRune)
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case rpsInStart:
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err = rp.handleInStart(curRune)
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case rpsExpectColon:
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err = rp.handleExpectColon(curRune)
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case rpsExpectEnd:
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rp.handleExpectEnd()
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case rpsInEnd:
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rp.handleInEnd(curRune)
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}
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Try to parse a string into a performance data range.
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func ParseRange(input string) (*Range, error) {
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parser := initRangeParser(input)
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if err := parser.consumeInput(); err != nil {
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return nil, err
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}
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if parser.state == rpsInStart {
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// The range was a single value, so that's the upper bound.
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parser.output.start = "0"
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parser.state = rpsInEnd
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}
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if parser.state != rpsInEnd {
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return nil, parseError(input, parser.index, "unexpected end of input")
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}
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parser.output.end = parser.strBuilder.String()
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if !valueCheck.MatchString(parser.output.end) {
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return nil, parseError(input, parser.startOfValue, "invalid end value")
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}
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return &parser.output, nil
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}
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66
pkg/perfdata/rangeparser_test.go
Normal file
66
pkg/perfdata/rangeparser_test.go
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@ -0,0 +1,66 @@
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package perfdata // import nocternity.net/gomonop/pkg/perfdata
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import (
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"fmt"
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"strings"
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"testing"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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func TestRangeParserOk(t *testing.T) {
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type Test struct {
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in string
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out Range
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}
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tests := []Test{
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{in: ":0", out: Range{start: "0", end: "0"}},
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{in: "0:0", out: Range{start: "0", end: "0"}},
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{in: "~:0", out: Range{start: "", end: "0"}},
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{in: ":123", out: Range{start: "0", end: "123"}},
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{in: "0:123", out: Range{start: "0", end: "123"}},
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{in: "~:123", out: Range{start: "", end: "123"}},
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{in: "1", out: Range{start: "0", end: "1"}},
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{in: "@:0", out: Range{start: "0", end: "0", inside: true}},
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{in: "@0:0", out: Range{start: "0", end: "0", inside: true}},
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{in: "@~:0", out: Range{start: "", end: "0", inside: true}},
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{in: "@:123", out: Range{start: "0", end: "123", inside: true}},
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{in: "@0:123", out: Range{start: "0", end: "123", inside: true}},
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{in: "@~:123", out: Range{start: "", end: "123", inside: true}},
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{in: "@1", out: Range{start: "0", end: "1", inside: true}},
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}
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for _, test := range tests {
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result, err := ParseRange(test.in)
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require.NoError(t, err, "Expected no error, got '%v'", err)
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assert.Equal(t, test.out, *result, "Expected '%v', got '%v'", test.out, *result)
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}
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}
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func TestRangeParserError(t *testing.T) {
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type Test struct {
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in string
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errPos int
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}
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tests := []Test{
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{in: "", errPos: 0},
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{in: ":", errPos: 1},
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{in: "x:1", errPos: 0},
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{in: ":~", errPos: 1},
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{in: "@", errPos: 1},
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{in: "@:", errPos: 2},
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{in: "@x:1", errPos: 1},
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{in: "@:~", errPos: 2},
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}
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for _, test := range tests {
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result, err := ParseRange(test.in)
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require.Error(t, err, "Expected error, got '%v'", err)
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assert.Nil(t, result, "Expected nil result, got '%v'", result)
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assert.True(
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t, strings.Contains(err.Error(), fmt.Sprintf("at position %d", test.errPos)),
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"Expected error to contain '%s', got '%s'", fmt.Sprintf("at position %d", test.errPos), err,
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)
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}
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}
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