mirror of
https://github.com/go-gitea/gitea
synced 2024-09-19 18:26:04 +00:00
9fe4437bda
* Use vendored go-swagger * vendor go-swagger * revert un wanteed change * remove un-needed GO111MODULE * Update Makefile Co-Authored-By: techknowlogick <matti@mdranta.net>
853 lines
20 KiB
Go
853 lines
20 KiB
Go
// Copyright 2016 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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// Binary package export.
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// This file was derived from $GOROOT/src/cmd/compile/internal/gc/bexport.go;
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// see that file for specification of the format.
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package gcimporter
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"go/ast"
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"go/constant"
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"go/token"
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"go/types"
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"math"
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"math/big"
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"sort"
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"strings"
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)
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// If debugFormat is set, each integer and string value is preceded by a marker
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// and position information in the encoding. This mechanism permits an importer
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// to recognize immediately when it is out of sync. The importer recognizes this
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// mode automatically (i.e., it can import export data produced with debugging
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// support even if debugFormat is not set at the time of import). This mode will
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// lead to massively larger export data (by a factor of 2 to 3) and should only
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// be enabled during development and debugging.
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//
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// NOTE: This flag is the first flag to enable if importing dies because of
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// (suspected) format errors, and whenever a change is made to the format.
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const debugFormat = false // default: false
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// If trace is set, debugging output is printed to std out.
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const trace = false // default: false
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// Current export format version. Increase with each format change.
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// Note: The latest binary (non-indexed) export format is at version 6.
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// This exporter is still at level 4, but it doesn't matter since
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// the binary importer can handle older versions just fine.
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// 6: package height (CL 105038) -- NOT IMPLEMENTED HERE
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// 5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMEMTED HERE
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// 4: type name objects support type aliases, uses aliasTag
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// 3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
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// 2: removed unused bool in ODCL export (compiler only)
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// 1: header format change (more regular), export package for _ struct fields
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// 0: Go1.7 encoding
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const exportVersion = 4
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// trackAllTypes enables cycle tracking for all types, not just named
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// types. The existing compiler invariants assume that unnamed types
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// that are not completely set up are not used, or else there are spurious
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// errors.
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// If disabled, only named types are tracked, possibly leading to slightly
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// less efficient encoding in rare cases. It also prevents the export of
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// some corner-case type declarations (but those are not handled correctly
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// with with the textual export format either).
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// TODO(gri) enable and remove once issues caused by it are fixed
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const trackAllTypes = false
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type exporter struct {
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fset *token.FileSet
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out bytes.Buffer
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// object -> index maps, indexed in order of serialization
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strIndex map[string]int
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pkgIndex map[*types.Package]int
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typIndex map[types.Type]int
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// position encoding
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posInfoFormat bool
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prevFile string
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prevLine int
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// debugging support
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written int // bytes written
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indent int // for trace
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}
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// internalError represents an error generated inside this package.
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type internalError string
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func (e internalError) Error() string { return "gcimporter: " + string(e) }
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func internalErrorf(format string, args ...interface{}) error {
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return internalError(fmt.Sprintf(format, args...))
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}
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// BExportData returns binary export data for pkg.
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// If no file set is provided, position info will be missing.
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func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
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defer func() {
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if e := recover(); e != nil {
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if ierr, ok := e.(internalError); ok {
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err = ierr
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return
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}
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// Not an internal error; panic again.
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panic(e)
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}
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}()
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p := exporter{
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fset: fset,
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strIndex: map[string]int{"": 0}, // empty string is mapped to 0
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pkgIndex: make(map[*types.Package]int),
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typIndex: make(map[types.Type]int),
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posInfoFormat: true, // TODO(gri) might become a flag, eventually
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}
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// write version info
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// The version string must start with "version %d" where %d is the version
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// number. Additional debugging information may follow after a blank; that
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// text is ignored by the importer.
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p.rawStringln(fmt.Sprintf("version %d", exportVersion))
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var debug string
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if debugFormat {
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debug = "debug"
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}
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p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
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p.bool(trackAllTypes)
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p.bool(p.posInfoFormat)
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// --- generic export data ---
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// populate type map with predeclared "known" types
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for index, typ := range predeclared() {
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p.typIndex[typ] = index
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}
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if len(p.typIndex) != len(predeclared()) {
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return nil, internalError("duplicate entries in type map?")
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}
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// write package data
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p.pkg(pkg, true)
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if trace {
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p.tracef("\n")
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}
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// write objects
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objcount := 0
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scope := pkg.Scope()
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for _, name := range scope.Names() {
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if !ast.IsExported(name) {
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continue
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}
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if trace {
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p.tracef("\n")
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}
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p.obj(scope.Lookup(name))
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objcount++
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}
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// indicate end of list
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if trace {
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p.tracef("\n")
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}
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p.tag(endTag)
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// for self-verification only (redundant)
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p.int(objcount)
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if trace {
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p.tracef("\n")
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}
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// --- end of export data ---
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return p.out.Bytes(), nil
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}
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func (p *exporter) pkg(pkg *types.Package, emptypath bool) {
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if pkg == nil {
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panic(internalError("unexpected nil pkg"))
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}
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// if we saw the package before, write its index (>= 0)
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if i, ok := p.pkgIndex[pkg]; ok {
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p.index('P', i)
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return
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}
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// otherwise, remember the package, write the package tag (< 0) and package data
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if trace {
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p.tracef("P%d = { ", len(p.pkgIndex))
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defer p.tracef("} ")
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}
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p.pkgIndex[pkg] = len(p.pkgIndex)
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p.tag(packageTag)
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p.string(pkg.Name())
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if emptypath {
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p.string("")
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} else {
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p.string(pkg.Path())
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}
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}
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func (p *exporter) obj(obj types.Object) {
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switch obj := obj.(type) {
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case *types.Const:
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p.tag(constTag)
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p.pos(obj)
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p.qualifiedName(obj)
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p.typ(obj.Type())
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p.value(obj.Val())
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case *types.TypeName:
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if obj.IsAlias() {
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p.tag(aliasTag)
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p.pos(obj)
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p.qualifiedName(obj)
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} else {
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p.tag(typeTag)
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}
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p.typ(obj.Type())
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case *types.Var:
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p.tag(varTag)
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p.pos(obj)
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p.qualifiedName(obj)
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p.typ(obj.Type())
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case *types.Func:
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p.tag(funcTag)
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p.pos(obj)
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p.qualifiedName(obj)
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sig := obj.Type().(*types.Signature)
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p.paramList(sig.Params(), sig.Variadic())
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p.paramList(sig.Results(), false)
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default:
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panic(internalErrorf("unexpected object %v (%T)", obj, obj))
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}
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}
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func (p *exporter) pos(obj types.Object) {
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if !p.posInfoFormat {
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return
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}
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file, line := p.fileLine(obj)
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if file == p.prevFile {
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// common case: write line delta
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// delta == 0 means different file or no line change
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delta := line - p.prevLine
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p.int(delta)
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if delta == 0 {
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p.int(-1) // -1 means no file change
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}
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} else {
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// different file
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p.int(0)
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// Encode filename as length of common prefix with previous
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// filename, followed by (possibly empty) suffix. Filenames
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// frequently share path prefixes, so this can save a lot
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// of space and make export data size less dependent on file
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// path length. The suffix is unlikely to be empty because
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// file names tend to end in ".go".
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n := commonPrefixLen(p.prevFile, file)
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p.int(n) // n >= 0
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p.string(file[n:]) // write suffix only
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p.prevFile = file
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p.int(line)
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}
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p.prevLine = line
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}
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func (p *exporter) fileLine(obj types.Object) (file string, line int) {
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if p.fset != nil {
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pos := p.fset.Position(obj.Pos())
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file = pos.Filename
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line = pos.Line
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}
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return
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}
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func commonPrefixLen(a, b string) int {
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if len(a) > len(b) {
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a, b = b, a
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}
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// len(a) <= len(b)
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i := 0
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for i < len(a) && a[i] == b[i] {
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i++
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}
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return i
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}
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func (p *exporter) qualifiedName(obj types.Object) {
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p.string(obj.Name())
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p.pkg(obj.Pkg(), false)
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}
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func (p *exporter) typ(t types.Type) {
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if t == nil {
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panic(internalError("nil type"))
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}
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// Possible optimization: Anonymous pointer types *T where
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// T is a named type are common. We could canonicalize all
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// such types *T to a single type PT = *T. This would lead
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// to at most one *T entry in typIndex, and all future *T's
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// would be encoded as the respective index directly. Would
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// save 1 byte (pointerTag) per *T and reduce the typIndex
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// size (at the cost of a canonicalization map). We can do
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// this later, without encoding format change.
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// if we saw the type before, write its index (>= 0)
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if i, ok := p.typIndex[t]; ok {
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p.index('T', i)
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return
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}
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// otherwise, remember the type, write the type tag (< 0) and type data
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if trackAllTypes {
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if trace {
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p.tracef("T%d = {>\n", len(p.typIndex))
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defer p.tracef("<\n} ")
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}
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p.typIndex[t] = len(p.typIndex)
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}
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switch t := t.(type) {
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case *types.Named:
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if !trackAllTypes {
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// if we don't track all types, track named types now
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p.typIndex[t] = len(p.typIndex)
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}
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p.tag(namedTag)
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p.pos(t.Obj())
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p.qualifiedName(t.Obj())
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p.typ(t.Underlying())
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if !types.IsInterface(t) {
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p.assocMethods(t)
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}
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case *types.Array:
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p.tag(arrayTag)
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p.int64(t.Len())
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p.typ(t.Elem())
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case *types.Slice:
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p.tag(sliceTag)
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p.typ(t.Elem())
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case *dddSlice:
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p.tag(dddTag)
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p.typ(t.elem)
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case *types.Struct:
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p.tag(structTag)
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p.fieldList(t)
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case *types.Pointer:
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p.tag(pointerTag)
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p.typ(t.Elem())
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case *types.Signature:
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p.tag(signatureTag)
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p.paramList(t.Params(), t.Variadic())
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p.paramList(t.Results(), false)
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case *types.Interface:
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p.tag(interfaceTag)
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p.iface(t)
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case *types.Map:
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p.tag(mapTag)
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p.typ(t.Key())
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p.typ(t.Elem())
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case *types.Chan:
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p.tag(chanTag)
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p.int(int(3 - t.Dir())) // hack
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p.typ(t.Elem())
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default:
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panic(internalErrorf("unexpected type %T: %s", t, t))
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}
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}
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func (p *exporter) assocMethods(named *types.Named) {
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// Sort methods (for determinism).
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var methods []*types.Func
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for i := 0; i < named.NumMethods(); i++ {
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methods = append(methods, named.Method(i))
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}
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sort.Sort(methodsByName(methods))
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p.int(len(methods))
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if trace && methods != nil {
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p.tracef("associated methods {>\n")
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}
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for i, m := range methods {
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if trace && i > 0 {
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p.tracef("\n")
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}
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p.pos(m)
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name := m.Name()
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p.string(name)
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if !exported(name) {
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p.pkg(m.Pkg(), false)
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}
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sig := m.Type().(*types.Signature)
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p.paramList(types.NewTuple(sig.Recv()), false)
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p.paramList(sig.Params(), sig.Variadic())
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p.paramList(sig.Results(), false)
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p.int(0) // dummy value for go:nointerface pragma - ignored by importer
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}
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if trace && methods != nil {
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p.tracef("<\n} ")
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}
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}
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type methodsByName []*types.Func
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func (x methodsByName) Len() int { return len(x) }
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func (x methodsByName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
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func (x methodsByName) Less(i, j int) bool { return x[i].Name() < x[j].Name() }
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func (p *exporter) fieldList(t *types.Struct) {
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if trace && t.NumFields() > 0 {
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p.tracef("fields {>\n")
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defer p.tracef("<\n} ")
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}
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p.int(t.NumFields())
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for i := 0; i < t.NumFields(); i++ {
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if trace && i > 0 {
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p.tracef("\n")
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}
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p.field(t.Field(i))
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p.string(t.Tag(i))
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}
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}
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func (p *exporter) field(f *types.Var) {
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if !f.IsField() {
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panic(internalError("field expected"))
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}
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p.pos(f)
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p.fieldName(f)
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p.typ(f.Type())
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}
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func (p *exporter) iface(t *types.Interface) {
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// TODO(gri): enable importer to load embedded interfaces,
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// then emit Embeddeds and ExplicitMethods separately here.
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p.int(0)
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n := t.NumMethods()
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if trace && n > 0 {
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p.tracef("methods {>\n")
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defer p.tracef("<\n} ")
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}
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p.int(n)
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for i := 0; i < n; i++ {
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if trace && i > 0 {
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p.tracef("\n")
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}
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p.method(t.Method(i))
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}
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}
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func (p *exporter) method(m *types.Func) {
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sig := m.Type().(*types.Signature)
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if sig.Recv() == nil {
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panic(internalError("method expected"))
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}
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p.pos(m)
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p.string(m.Name())
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if m.Name() != "_" && !ast.IsExported(m.Name()) {
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p.pkg(m.Pkg(), false)
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}
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|
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// interface method; no need to encode receiver.
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p.paramList(sig.Params(), sig.Variadic())
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p.paramList(sig.Results(), false)
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}
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|
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func (p *exporter) fieldName(f *types.Var) {
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name := f.Name()
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|
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if f.Anonymous() {
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// anonymous field - we distinguish between 3 cases:
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// 1) field name matches base type name and is exported
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// 2) field name matches base type name and is not exported
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// 3) field name doesn't match base type name (alias name)
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bname := basetypeName(f.Type())
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if name == bname {
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if ast.IsExported(name) {
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name = "" // 1) we don't need to know the field name or package
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} else {
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name = "?" // 2) use unexported name "?" to force package export
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}
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} else {
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// 3) indicate alias and export name as is
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// (this requires an extra "@" but this is a rare case)
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p.string("@")
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}
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}
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p.string(name)
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if name != "" && !ast.IsExported(name) {
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p.pkg(f.Pkg(), false)
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}
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}
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|
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func basetypeName(typ types.Type) string {
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switch typ := deref(typ).(type) {
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case *types.Basic:
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return typ.Name()
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case *types.Named:
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return typ.Obj().Name()
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default:
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return "" // unnamed type
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}
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}
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|
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func (p *exporter) paramList(params *types.Tuple, variadic bool) {
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|
// use negative length to indicate unnamed parameters
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|
// (look at the first parameter only since either all
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// names are present or all are absent)
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n := params.Len()
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if n > 0 && params.At(0).Name() == "" {
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n = -n
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}
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p.int(n)
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for i := 0; i < params.Len(); i++ {
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q := params.At(i)
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t := q.Type()
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|
if variadic && i == params.Len()-1 {
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t = &dddSlice{t.(*types.Slice).Elem()}
|
|
}
|
|
p.typ(t)
|
|
if n > 0 {
|
|
name := q.Name()
|
|
p.string(name)
|
|
if name != "_" {
|
|
p.pkg(q.Pkg(), false)
|
|
}
|
|
}
|
|
p.string("") // no compiler-specific info
|
|
}
|
|
}
|
|
|
|
func (p *exporter) value(x constant.Value) {
|
|
if trace {
|
|
p.tracef("= ")
|
|
}
|
|
|
|
switch x.Kind() {
|
|
case constant.Bool:
|
|
tag := falseTag
|
|
if constant.BoolVal(x) {
|
|
tag = trueTag
|
|
}
|
|
p.tag(tag)
|
|
|
|
case constant.Int:
|
|
if v, exact := constant.Int64Val(x); exact {
|
|
// common case: x fits into an int64 - use compact encoding
|
|
p.tag(int64Tag)
|
|
p.int64(v)
|
|
return
|
|
}
|
|
// uncommon case: large x - use float encoding
|
|
// (powers of 2 will be encoded efficiently with exponent)
|
|
p.tag(floatTag)
|
|
p.float(constant.ToFloat(x))
|
|
|
|
case constant.Float:
|
|
p.tag(floatTag)
|
|
p.float(x)
|
|
|
|
case constant.Complex:
|
|
p.tag(complexTag)
|
|
p.float(constant.Real(x))
|
|
p.float(constant.Imag(x))
|
|
|
|
case constant.String:
|
|
p.tag(stringTag)
|
|
p.string(constant.StringVal(x))
|
|
|
|
case constant.Unknown:
|
|
// package contains type errors
|
|
p.tag(unknownTag)
|
|
|
|
default:
|
|
panic(internalErrorf("unexpected value %v (%T)", x, x))
|
|
}
|
|
}
|
|
|
|
func (p *exporter) float(x constant.Value) {
|
|
if x.Kind() != constant.Float {
|
|
panic(internalErrorf("unexpected constant %v, want float", x))
|
|
}
|
|
// extract sign (there is no -0)
|
|
sign := constant.Sign(x)
|
|
if sign == 0 {
|
|
// x == 0
|
|
p.int(0)
|
|
return
|
|
}
|
|
// x != 0
|
|
|
|
var f big.Float
|
|
if v, exact := constant.Float64Val(x); exact {
|
|
// float64
|
|
f.SetFloat64(v)
|
|
} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
|
|
// TODO(gri): add big.Rat accessor to constant.Value.
|
|
r := valueToRat(num)
|
|
f.SetRat(r.Quo(r, valueToRat(denom)))
|
|
} else {
|
|
// Value too large to represent as a fraction => inaccessible.
|
|
// TODO(gri): add big.Float accessor to constant.Value.
|
|
f.SetFloat64(math.MaxFloat64) // FIXME
|
|
}
|
|
|
|
// extract exponent such that 0.5 <= m < 1.0
|
|
var m big.Float
|
|
exp := f.MantExp(&m)
|
|
|
|
// extract mantissa as *big.Int
|
|
// - set exponent large enough so mant satisfies mant.IsInt()
|
|
// - get *big.Int from mant
|
|
m.SetMantExp(&m, int(m.MinPrec()))
|
|
mant, acc := m.Int(nil)
|
|
if acc != big.Exact {
|
|
panic(internalError("internal error"))
|
|
}
|
|
|
|
p.int(sign)
|
|
p.int(exp)
|
|
p.string(string(mant.Bytes()))
|
|
}
|
|
|
|
func valueToRat(x constant.Value) *big.Rat {
|
|
// Convert little-endian to big-endian.
|
|
// I can't believe this is necessary.
|
|
bytes := constant.Bytes(x)
|
|
for i := 0; i < len(bytes)/2; i++ {
|
|
bytes[i], bytes[len(bytes)-1-i] = bytes[len(bytes)-1-i], bytes[i]
|
|
}
|
|
return new(big.Rat).SetInt(new(big.Int).SetBytes(bytes))
|
|
}
|
|
|
|
func (p *exporter) bool(b bool) bool {
|
|
if trace {
|
|
p.tracef("[")
|
|
defer p.tracef("= %v] ", b)
|
|
}
|
|
|
|
x := 0
|
|
if b {
|
|
x = 1
|
|
}
|
|
p.int(x)
|
|
return b
|
|
}
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// Low-level encoders
|
|
|
|
func (p *exporter) index(marker byte, index int) {
|
|
if index < 0 {
|
|
panic(internalError("invalid index < 0"))
|
|
}
|
|
if debugFormat {
|
|
p.marker('t')
|
|
}
|
|
if trace {
|
|
p.tracef("%c%d ", marker, index)
|
|
}
|
|
p.rawInt64(int64(index))
|
|
}
|
|
|
|
func (p *exporter) tag(tag int) {
|
|
if tag >= 0 {
|
|
panic(internalError("invalid tag >= 0"))
|
|
}
|
|
if debugFormat {
|
|
p.marker('t')
|
|
}
|
|
if trace {
|
|
p.tracef("%s ", tagString[-tag])
|
|
}
|
|
p.rawInt64(int64(tag))
|
|
}
|
|
|
|
func (p *exporter) int(x int) {
|
|
p.int64(int64(x))
|
|
}
|
|
|
|
func (p *exporter) int64(x int64) {
|
|
if debugFormat {
|
|
p.marker('i')
|
|
}
|
|
if trace {
|
|
p.tracef("%d ", x)
|
|
}
|
|
p.rawInt64(x)
|
|
}
|
|
|
|
func (p *exporter) string(s string) {
|
|
if debugFormat {
|
|
p.marker('s')
|
|
}
|
|
if trace {
|
|
p.tracef("%q ", s)
|
|
}
|
|
// if we saw the string before, write its index (>= 0)
|
|
// (the empty string is mapped to 0)
|
|
if i, ok := p.strIndex[s]; ok {
|
|
p.rawInt64(int64(i))
|
|
return
|
|
}
|
|
// otherwise, remember string and write its negative length and bytes
|
|
p.strIndex[s] = len(p.strIndex)
|
|
p.rawInt64(-int64(len(s)))
|
|
for i := 0; i < len(s); i++ {
|
|
p.rawByte(s[i])
|
|
}
|
|
}
|
|
|
|
// marker emits a marker byte and position information which makes
|
|
// it easy for a reader to detect if it is "out of sync". Used for
|
|
// debugFormat format only.
|
|
func (p *exporter) marker(m byte) {
|
|
p.rawByte(m)
|
|
// Enable this for help tracking down the location
|
|
// of an incorrect marker when running in debugFormat.
|
|
if false && trace {
|
|
p.tracef("#%d ", p.written)
|
|
}
|
|
p.rawInt64(int64(p.written))
|
|
}
|
|
|
|
// rawInt64 should only be used by low-level encoders.
|
|
func (p *exporter) rawInt64(x int64) {
|
|
var tmp [binary.MaxVarintLen64]byte
|
|
n := binary.PutVarint(tmp[:], x)
|
|
for i := 0; i < n; i++ {
|
|
p.rawByte(tmp[i])
|
|
}
|
|
}
|
|
|
|
// rawStringln should only be used to emit the initial version string.
|
|
func (p *exporter) rawStringln(s string) {
|
|
for i := 0; i < len(s); i++ {
|
|
p.rawByte(s[i])
|
|
}
|
|
p.rawByte('\n')
|
|
}
|
|
|
|
// rawByte is the bottleneck interface to write to p.out.
|
|
// rawByte escapes b as follows (any encoding does that
|
|
// hides '$'):
|
|
//
|
|
// '$' => '|' 'S'
|
|
// '|' => '|' '|'
|
|
//
|
|
// Necessary so other tools can find the end of the
|
|
// export data by searching for "$$".
|
|
// rawByte should only be used by low-level encoders.
|
|
func (p *exporter) rawByte(b byte) {
|
|
switch b {
|
|
case '$':
|
|
// write '$' as '|' 'S'
|
|
b = 'S'
|
|
fallthrough
|
|
case '|':
|
|
// write '|' as '|' '|'
|
|
p.out.WriteByte('|')
|
|
p.written++
|
|
}
|
|
p.out.WriteByte(b)
|
|
p.written++
|
|
}
|
|
|
|
// tracef is like fmt.Printf but it rewrites the format string
|
|
// to take care of indentation.
|
|
func (p *exporter) tracef(format string, args ...interface{}) {
|
|
if strings.ContainsAny(format, "<>\n") {
|
|
var buf bytes.Buffer
|
|
for i := 0; i < len(format); i++ {
|
|
// no need to deal with runes
|
|
ch := format[i]
|
|
switch ch {
|
|
case '>':
|
|
p.indent++
|
|
continue
|
|
case '<':
|
|
p.indent--
|
|
continue
|
|
}
|
|
buf.WriteByte(ch)
|
|
if ch == '\n' {
|
|
for j := p.indent; j > 0; j-- {
|
|
buf.WriteString(". ")
|
|
}
|
|
}
|
|
}
|
|
format = buf.String()
|
|
}
|
|
fmt.Printf(format, args...)
|
|
}
|
|
|
|
// Debugging support.
|
|
// (tagString is only used when tracing is enabled)
|
|
var tagString = [...]string{
|
|
// Packages
|
|
-packageTag: "package",
|
|
|
|
// Types
|
|
-namedTag: "named type",
|
|
-arrayTag: "array",
|
|
-sliceTag: "slice",
|
|
-dddTag: "ddd",
|
|
-structTag: "struct",
|
|
-pointerTag: "pointer",
|
|
-signatureTag: "signature",
|
|
-interfaceTag: "interface",
|
|
-mapTag: "map",
|
|
-chanTag: "chan",
|
|
|
|
// Values
|
|
-falseTag: "false",
|
|
-trueTag: "true",
|
|
-int64Tag: "int64",
|
|
-floatTag: "float",
|
|
-fractionTag: "fraction",
|
|
-complexTag: "complex",
|
|
-stringTag: "string",
|
|
-unknownTag: "unknown",
|
|
|
|
// Type aliases
|
|
-aliasTag: "alias",
|
|
}
|