more cleanup

message.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"bytes"
-	"fmt"
 	"strings"
 )
 
@@ -11,12 +10,13 @@ type Tag struct {
 	Value string
 }
 
-// Tags is an key-order-preserving, last-insert-wins "set" of Tag
+// Tags is an key-order-preserving, last-insert-wins "set" of Tag{}s
 type Tags struct {
 	kv   map[string]int // quick lookups for inserts
 	tags []Tag
 }
 
+// Insert adds the given tag to the set, overriding any existing tag with that Key
 func (t *Tags) Insert(new Tag) {
 	if t.kv == nil {
 		t.kv = map[string]int{}
@@ -30,38 +30,54 @@ func (t *Tags) Insert(new Tag) {
 	}
 }
 
+// GetSlice returns a simple slice of tags from the set
 func (t *Tags) GetSlice() []Tag {
 	return t.tags
 }
 
+// A Message represents a parsed set of Tags/Source/Command/Parameters from a Raw string.
+//
+// Tags/Source/Command/Parameters are all set from the Raw after ParseMessage() is called.
+// Calling ParseMessage multiple times (without changing Raw) should be a no-op.
+//
+// Canonicalize() returns Tags/Source/Command/Parameters transformed back into an RFC-compliant []byte.
+//
+// Reusing a message struct to parse multiple Raw messages is possible, but frowned upon.
+//
+// Tag values are automatically escaped during parsing.
 type Message struct {
-	Tags       []Tag
+	Tags       []Tag    // An ordered slice of Key=Value pairs
-	Source     string
+	Source     string   // An optional string denoting the source of the message
-	Command    command
+	Command    command  // A command/numeric for the message
-	Parameters []string
+	Parameters []string // Zero or more parameters for the Command.
 	Raw        string
 
 	parseIndex int
 }
 
-func (m *Message) ParseMessage() error {
+// ParseMessage will attempt to parse whatever it's given as an IRC Message,
+// and populate Tags/Source/Command/Parameters with the results.
+// Garbage in, garbage out, though. The parser tries its best, but doesn't aggressively
+// validate messages.
+//
+// Tag values are automatically escaped during parsing, as needed.
+func (m *Message) ParseMessage() {
 	m.parseIndex = 0
 	m.consumeSpaces()
 	if m.consume('@') {
-		m.Tags, _ = m.parseTags()
+		m.Tags = m.parseTags()
 	}
 	m.consumeSpaces()
 	if m.consume(':') {
-		m.Source, _ = m.parseSource()
+		m.Source = m.parseSource()
 	}
 	m.consumeSpaces()
-	m.Command, _ = m.parseCommand()
+	m.Command = m.parseCommand()
 	m.consumeSpaces()
-	m.Parameters, _ = m.parseParameters()
+	m.Parameters = m.parseParameters()
-	return nil
 }
 
-func (m *Message) parseTags() ([]Tag, error) {
+func (m *Message) parseTags() []Tag {
 	tags := &Tags{}
 	for {
 		next := m.findNext("=", ";")
@@ -71,30 +87,34 @@ func (m *Message) parseTags() ([]Tag, error) {
 			key := m.Raw[m.parseIndex : m.parseIndex+next]
 			m.parseIndex += next + 1
 			eot := m.findNext(";", " ")
+			if eot == -1 { // ran out of message, probably
+				tags.Insert(Tag{Key: key, Value: unescapeTag(m.Raw[m.parseIndex:])})
+				m.parseIndex = len(m.Raw)
+				break
+			}
 			tags.Insert(Tag{Key: key, Value: unescapeTag(m.Raw[m.parseIndex : m.parseIndex+eot])})
 			m.parseIndex += len(m.Raw[m.parseIndex:m.parseIndex+eot]) + 1
 		} else if m.Raw[m.parseIndex+next] == ';' {
 			key := m.Raw[m.parseIndex : m.parseIndex+next]
 			m.parseIndex += next + 1
 			tags.Insert(Tag{Key: key, Value: ""})
-		} else {
-			break
 		}
 	}
-	return tags.GetSlice(), nil
+	return tags.GetSlice()
 }
 
-func (m *Message) parseSource() (string, error) {
+func (m *Message) parseSource() string {
 	start := m.parseIndex
 	endofparse := strings.Index(m.Raw[m.parseIndex:], " ")
 	if endofparse == -1 {
-		return "", fmt.Errorf("end of string encountered while parsing tags")
+		m.parseIndex = len(m.Raw) // out of message! which is weird.
-	}
+	} else {
 		m.parseIndex += endofparse
-	return m.Raw[start:m.parseIndex], nil
+	}
+	return m.Raw[start:m.parseIndex]
 }
 
-func (m *Message) parseCommand() (command, error) {
+func (m *Message) parseCommand() command {
 	start := m.parseIndex
 	endofparse := strings.Index(m.Raw[m.parseIndex:], " ")
 	if endofparse == -1 {
@@ -102,10 +122,10 @@ func (m *Message) parseCommand() (command, error) {
 	} else {
 		m.parseIndex += endofparse
 	}
-	return command(m.Raw[start:m.parseIndex]), nil
+	return command(m.Raw[start:m.parseIndex])
 }
 
-func (m *Message) parseParameters() ([]string, error) {
+func (m *Message) parseParameters() []string {
 	params := []string{}
 	for m.parseIndex <= len(m.Raw) {
 		m.consumeSpaces()
@@ -114,17 +134,13 @@ func (m *Message) parseParameters() ([]string, error) {
 			break
 		}
 		endofparse := strings.Index(m.Raw[m.parseIndex:], " ")
-		if endofparse == -1 { // no further params after this one
+		if endofparse == -1 { // no further params
-			p := strings.TrimSuffix(m.Raw[m.parseIndex:], " ")
-			if len(p) > 0 { // reject empty trailing params
-				params = append(params, p)
-			}
 			break
 		}
 		params = append(params, m.Raw[m.parseIndex:m.parseIndex+endofparse])
 		m.parseIndex += endofparse
 	}
-	return params, nil
+	return params
 }
 
 func (m *Message) consumeSpaces() {
@@ -148,9 +164,6 @@ func (m *Message) consume(r byte) bool {
 }
 
 func (m *Message) findNext(bs ...string) int {
-	if len(bs) == 0 {
-		return 0
-	}
 	r := -1
 	for _, b := range bs {
 		i := strings.Index(m.Raw[m.parseIndex:], b)
@@ -167,9 +180,6 @@ func unescapeTag(s string) string {
 	i := 0
 	for i < len(s) {
 		if escaping {
-			if i+1 > len(s) {
-				break
-			}
 			switch s[i] {
 			case ':':
 				sb.WriteByte(';')

message_test.go

@@ -136,6 +136,12 @@ func TestParsing(t *testing.T) {
 				Tags:    []Tag{{"tag1", `value`}},
 				Command: command("COMMAND"),
 			}},
+		{
+			input: `@tag1=va\r\nlue COMMAND`,
+			output: &Message{
+				Tags:    []Tag{{"tag1", "va\r\nlue"}},
+				Command: command("COMMAND"),
+			}},
 		{
 			input: `@tag1=1;tag2=3;tag3=4;tag1=5 COMMAND`,
 			output: &Message{
@@ -162,6 +168,24 @@ func TestParsing(t *testing.T) {
 				Command:    MODE,
 				Parameters: []string{"#channel", "+oo", "SomeUser", "AnotherUser"},
 			}},
+		{
+			input: `:uttergarbage`,
+			output: &Message{
+				Source: "uttergarbage",
+			},
+		},
+		{
+			input: `@only=tags`,
+			output: &Message{
+				Tags: []Tag{{"only", "tags"}},
+			},
+		},
+		{
+			input: `@only=`,
+			output: &Message{
+				Tags: []Tag{{"only", ""}},
+			},
+		},
 	}
 	for _, tc := range testcases {
 		m := &Message{Raw: tc.input}
@@ -305,6 +329,13 @@ func TestCanonicalization(t *testing.T) {
 			},
 			output: `@tag1=value\\ntest COMMAND`,
 		},
+		{
+			input: &Message{
+				Tags:    []Tag{{"tag1", "va\r\nlue"}},
+				Command: command("COMMAND"),
+			},
+			output: `@tag1=va\r\nlue COMMAND`,
+		},
 	}
 	for _, tc := range testcases {
 		output := string(tc.input.Canonicalize())
@@ -314,3 +345,14 @@ func TestCanonicalization(t *testing.T) {
 		}
 	}
 }
+
+func TestRoundTrip(t *testing.T) {
+	in := `@a=b;c=3\n2;k;rt=ql7 :dan!d@localhost PRIVMSG #chan :Hey what's up! `
+	m := &Message{Raw: in}
+	m.ParseMessage()
+	out := m.Canonicalize()
+	if string(out) != in {
+		t.Logf("expected '%s', received '%s'", in, string(out))
+		t.Fail()
+	}
+}