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template: fix deadlock.

No need for lexInsideAction to loop.
Fixes #2217.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4963054
This commit is contained in:
Rob Pike 2011-09-02 11:00:46 +10:00
parent 5edeef214d
commit 2cf66c1d94
2 changed files with 58 additions and 46 deletions

View File

@ -278,53 +278,51 @@ func lexInsideAction(l *lexer) stateFn {
// Either number, quoted string, or identifier.
// Spaces separate and are ignored.
// Pipe symbols separate and are emitted.
for {
if strings.HasPrefix(l.input[l.pos:], rightDelim) {
return lexRightDelim
}
switch r := l.next(); {
case r == eof || r == '\n':
return l.errorf("unclosed action")
case isSpace(r):
l.ignore()
case r == ':':
if l.next() != '=' {
return l.errorf("expected :=")
}
l.emit(itemColonEquals)
case r == '|':
l.emit(itemPipe)
case r == '"':
return lexQuote
case r == '`':
return lexRawQuote
case r == '$':
return lexIdentifier
case r == '\'':
return lexChar
case r == '.':
// special look-ahead for ".field" so we don't break l.backup().
if l.pos < len(l.input) {
r := l.input[l.pos]
if r < '0' || '9' < r {
return lexIdentifier // itemDot comes from the keyword table.
}
}
fallthrough // '.' can start a number.
case r == '+' || r == '-' || ('0' <= r && r <= '9'):
l.backup()
return lexNumber
case isAlphaNumeric(r):
l.backup()
return lexIdentifier
case r <= unicode.MaxASCII && unicode.IsPrint(r):
l.emit(itemChar)
return lexInsideAction
default:
return l.errorf("unrecognized character in action: %#U", r)
}
if strings.HasPrefix(l.input[l.pos:], rightDelim) {
return lexRightDelim
}
return nil
switch r := l.next(); {
case r == eof || r == '\n':
return l.errorf("unclosed action")
case isSpace(r):
l.ignore()
case r == ':':
if l.next() != '=' {
return l.errorf("expected :=")
}
l.emit(itemColonEquals)
case r == '|':
l.emit(itemPipe)
case r == '"':
return lexQuote
case r == '`':
return lexRawQuote
case r == '$':
return lexIdentifier
case r == '\'':
return lexChar
case r == '.':
// special look-ahead for ".field" so we don't break l.backup().
if l.pos < len(l.input) {
r := l.input[l.pos]
if r < '0' || '9' < r {
return lexIdentifier // itemDot comes from the keyword table.
}
}
fallthrough // '.' can start a number.
case r == '+' || r == '-' || ('0' <= r && r <= '9'):
l.backup()
return lexNumber
case isAlphaNumeric(r):
l.backup()
return lexIdentifier
case r <= unicode.MaxASCII && unicode.IsPrint(r):
l.emit(itemChar)
return lexInsideAction
default:
return l.errorf("unrecognized character in action: %#U", r)
}
return lexInsideAction
}
// lexIdentifier scans an alphanumeric or field.

View File

@ -184,6 +184,20 @@ var lexTests = []lexTest{
tLeft,
{itemError, `bad number syntax: "3k"`},
}},
// Fixed bugs
// Many elements in an action blew the lookahead until
// we made lexInsideAction not loop.
{"long pipeline deadlock", "{{|||||}}", []item{
tLeft,
tPipe,
tPipe,
tPipe,
tPipe,
tPipe,
tRight,
tEOF,
}},
}
// collect gathers the emitted items into a slice.