mirror of
https://github.com/golang/go
synced 2024-11-18 10:54:40 -07:00
67 lines
1.7 KiB
Go
67 lines
1.7 KiB
Go
|
// Copyright 2013 The Go Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style
|
||
|
|
// license that can be found in the LICENSE file.
|
||
|
|
|
||
|
|
package godoc
|
||
|
|
|
||
|
|
// ----------------------------------------------------------------------------
|
||
|
|
// SpotInfo
|
||
|
|
|
||
|
|
// A SpotInfo value describes a particular identifier spot in a given file;
|
||
|
|
// It encodes three values: the SpotKind (declaration or use), a line or
|
||
|
|
// snippet index "lori", and whether it's a line or index.
|
||
|
|
//
|
||
|
|
// The following encoding is used:
|
||
|
|
//
|
||
|
|
// bits 32 4 1 0
|
||
|
|
// value [lori|kind|isIndex]
|
||
|
|
//
|
||
|
|
type SpotInfo uint32
|
||
|
|
|
||
|
|
// SpotKind describes whether an identifier is declared (and what kind of
|
||
|
|
// declaration) or used.
|
||
|
|
type SpotKind uint32
|
||
|
|
|
||
|
|
const (
|
||
|
|
PackageClause SpotKind = iota
|
||
|
|
ImportDecl
|
||
|
|
ConstDecl
|
||
|
|
TypeDecl
|
||
|
|
VarDecl
|
||
|
|
FuncDecl
|
||
|
|
MethodDecl
|
||
|
|
Use
|
||
|
|
nKinds
|
||
|
|
)
|
||
|
|
|
||
|
|
func init() {
|
||
|
|
// sanity check: if nKinds is too large, the SpotInfo
|
||
|
|
// accessor functions may need to be updated
|
||
|
|
if nKinds > 8 {
|
||
|
|
panic("internal error: nKinds > 8")
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// makeSpotInfo makes a SpotInfo.
|
||
|
|
func makeSpotInfo(kind SpotKind, lori int, isIndex bool) SpotInfo {
|
||
|
|
// encode lori: bits [4..32)
|
||
|
|
x := SpotInfo(lori) << 4
|
||
|
|
if int(x>>4) != lori {
|
||
|
|
// lori value doesn't fit - since snippet indices are
|
||
|
|
// most certainly always smaller then 1<<28, this can
|
||
|
|
// only happen for line numbers; give it no line number (= 0)
|
||
|
|
x = 0
|
||
|
|
}
|
||
|
|
// encode kind: bits [1..4)
|
||
|
|
x |= SpotInfo(kind) << 1
|
||
|
|
// encode isIndex: bit 0
|
||
|
|
if isIndex {
|
||
|
|
x |= 1
|
||
|
|
}
|
||
|
|
return x
|
||
|
|
}
|
||
|
|
|
||
|
|
func (x SpotInfo) Kind() SpotKind { return SpotKind(x >> 1 & 7) }
|
||
|
|
func (x SpotInfo) Lori() int { return int(x >> 4) }
|
||
|
|
func (x SpotInfo) IsIndex() bool { return x&1 != 0 }
|