124 lines
3.2 KiB
Go
124 lines
3.2 KiB
Go
// Copyright 2009 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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// This file contains the infrastructure to create a code
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// snippet for search results.
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//
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// Note: At the moment, this only creates HTML snippets.
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package godoc
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import (
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"bytes"
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"fmt"
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"go/ast"
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"go/token"
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)
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type Snippet struct {
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Line int
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Text string // HTML-escaped
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}
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func (p *Presentation) newSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet {
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// TODO instead of pretty-printing the node, should use the original source instead
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var buf1 bytes.Buffer
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p.writeNode(&buf1, fset, decl)
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// wrap text with <pre> tag
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var buf2 bytes.Buffer
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buf2.WriteString("<pre>")
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FormatText(&buf2, buf1.Bytes(), -1, true, id.Name, nil)
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buf2.WriteString("</pre>")
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return &Snippet{fset.Position(id.Pos()).Line, buf2.String()}
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}
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func findSpec(list []ast.Spec, id *ast.Ident) ast.Spec {
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for _, spec := range list {
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switch s := spec.(type) {
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case *ast.ImportSpec:
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if s.Name == id {
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return s
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}
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case *ast.ValueSpec:
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for _, n := range s.Names {
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if n == id {
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return s
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}
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}
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case *ast.TypeSpec:
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if s.Name == id {
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return s
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}
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}
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}
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return nil
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}
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func (p *Presentation) genSnippet(fset *token.FileSet, d *ast.GenDecl, id *ast.Ident) *Snippet {
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s := findSpec(d.Specs, id)
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if s == nil {
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return nil // declaration doesn't contain id - exit gracefully
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}
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// only use the spec containing the id for the snippet
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dd := &ast.GenDecl{
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Doc: d.Doc,
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TokPos: d.Pos(),
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Tok: d.Tok,
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Lparen: d.Lparen,
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Specs: []ast.Spec{s},
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Rparen: d.Rparen,
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}
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return p.newSnippet(fset, dd, id)
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}
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func (p *Presentation) funcSnippet(fset *token.FileSet, d *ast.FuncDecl, id *ast.Ident) *Snippet {
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if d.Name != id {
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return nil // declaration doesn't contain id - exit gracefully
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}
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// only use the function signature for the snippet
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dd := &ast.FuncDecl{
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Doc: d.Doc,
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Recv: d.Recv,
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Name: d.Name,
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Type: d.Type,
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}
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return p.newSnippet(fset, dd, id)
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}
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// NewSnippet creates a text snippet from a declaration decl containing an
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// identifier id. Parts of the declaration not containing the identifier
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// may be removed for a more compact snippet.
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func NewSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet {
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// TODO(bradfitz, adg): remove this function. But it's used by indexer, which
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// doesn't have a *Presentation, and NewSnippet needs a TabWidth.
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var p Presentation
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p.TabWidth = 4
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return p.NewSnippet(fset, decl, id)
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}
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// NewSnippet creates a text snippet from a declaration decl containing an
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// identifier id. Parts of the declaration not containing the identifier
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// may be removed for a more compact snippet.
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func (p *Presentation) NewSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet {
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var s *Snippet
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switch d := decl.(type) {
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case *ast.GenDecl:
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s = p.genSnippet(fset, d, id)
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case *ast.FuncDecl:
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s = p.funcSnippet(fset, d, id)
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}
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// handle failure gracefully
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if s == nil {
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var buf bytes.Buffer
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fmt.Fprintf(&buf, `<span class="alert">could not generate a snippet for <span class="highlight">%s</span></span>`, id.Name)
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s = &Snippet{fset.Position(id.Pos()).Line, buf.String()}
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}
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return s
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}
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