| 1 | // Copyright 2009 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // This file contains the infrastructure to create a code |
| 6 | // snippet for search results. |
| 7 | // |
| 8 | // Note: At the moment, this only creates HTML snippets. |
| 9 | |
| 10 | package godoc |
| 11 | |
| 12 | import ( |
| 13 | "bytes" |
| 14 | "fmt" |
| 15 | "go/ast" |
| 16 | "go/token" |
| 17 | ) |
| 18 | |
| 19 | type Snippet struct { |
| 20 | Line int |
| 21 | Text string // HTML-escaped |
| 22 | } |
| 23 | |
| 24 | func (p *Presentation) newSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet { |
| 25 | // TODO instead of pretty-printing the node, should use the original source instead |
| 26 | var buf1 bytes.Buffer |
| 27 | p.writeNode(&buf1, nil, fset, decl) |
| 28 | // wrap text with <pre> tag |
| 29 | var buf2 bytes.Buffer |
| 30 | buf2.WriteString("<pre>") |
| 31 | FormatText(&buf2, buf1.Bytes(), -1, true, id.Name, nil) |
| 32 | buf2.WriteString("</pre>") |
| 33 | return &Snippet{fset.Position(id.Pos()).Line, buf2.String()} |
| 34 | } |
| 35 | |
| 36 | func findSpec(list []ast.Spec, id *ast.Ident) ast.Spec { |
| 37 | for _, spec := range list { |
| 38 | switch s := spec.(type) { |
| 39 | case *ast.ImportSpec: |
| 40 | if s.Name == id { |
| 41 | return s |
| 42 | } |
| 43 | case *ast.ValueSpec: |
| 44 | for _, n := range s.Names { |
| 45 | if n == id { |
| 46 | return s |
| 47 | } |
| 48 | } |
| 49 | case *ast.TypeSpec: |
| 50 | if s.Name == id { |
| 51 | return s |
| 52 | } |
| 53 | } |
| 54 | } |
| 55 | return nil |
| 56 | } |
| 57 | |
| 58 | func (p *Presentation) genSnippet(fset *token.FileSet, d *ast.GenDecl, id *ast.Ident) *Snippet { |
| 59 | s := findSpec(d.Specs, id) |
| 60 | if s == nil { |
| 61 | return nil // declaration doesn't contain id - exit gracefully |
| 62 | } |
| 63 | |
| 64 | // only use the spec containing the id for the snippet |
| 65 | dd := &ast.GenDecl{ |
| 66 | Doc: d.Doc, |
| 67 | TokPos: d.Pos(), |
| 68 | Tok: d.Tok, |
| 69 | Lparen: d.Lparen, |
| 70 | Specs: []ast.Spec{s}, |
| 71 | Rparen: d.Rparen, |
| 72 | } |
| 73 | |
| 74 | return p.newSnippet(fset, dd, id) |
| 75 | } |
| 76 | |
| 77 | func (p *Presentation) funcSnippet(fset *token.FileSet, d *ast.FuncDecl, id *ast.Ident) *Snippet { |
| 78 | if d.Name != id { |
| 79 | return nil // declaration doesn't contain id - exit gracefully |
| 80 | } |
| 81 | |
| 82 | // only use the function signature for the snippet |
| 83 | dd := &ast.FuncDecl{ |
| 84 | Doc: d.Doc, |
| 85 | Recv: d.Recv, |
| 86 | Name: d.Name, |
| 87 | Type: d.Type, |
| 88 | } |
| 89 | |
| 90 | return p.newSnippet(fset, dd, id) |
| 91 | } |
| 92 | |
| 93 | // NewSnippet creates a text snippet from a declaration decl containing an |
| 94 | // identifier id. Parts of the declaration not containing the identifier |
| 95 | // may be removed for a more compact snippet. |
| 96 | func NewSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet { |
| 97 | // TODO(bradfitz, adg): remove this function. But it's used by indexer, which |
| 98 | // doesn't have a *Presentation, and NewSnippet needs a TabWidth. |
| 99 | var p Presentation |
| 100 | p.TabWidth = 4 |
| 101 | return p.NewSnippet(fset, decl, id) |
| 102 | } |
| 103 | |
| 104 | // NewSnippet creates a text snippet from a declaration decl containing an |
| 105 | // identifier id. Parts of the declaration not containing the identifier |
| 106 | // may be removed for a more compact snippet. |
| 107 | func (p *Presentation) NewSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet { |
| 108 | var s *Snippet |
| 109 | switch d := decl.(type) { |
| 110 | case *ast.GenDecl: |
| 111 | s = p.genSnippet(fset, d, id) |
| 112 | case *ast.FuncDecl: |
| 113 | s = p.funcSnippet(fset, d, id) |
| 114 | } |
| 115 | |
| 116 | // handle failure gracefully |
| 117 | if s == nil { |
| 118 | var buf bytes.Buffer |
| 119 | fmt.Fprintf(&buf, `<span class="alert">could not generate a snippet for <span class="highlight">%s</span></span>`, id.Name) |
| 120 | s = &Snippet{fset.Position(id.Pos()).Line, buf.String()} |
| 121 | } |
| 122 | return s |
| 123 | } |
| 124 |
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