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