Matthias Andreas Benkard | 832a54e | 2019-01-29 09:27:38 +0100 | [diff] [blame] | 1 | /* |
| 2 | Copyright 2015 The Kubernetes Authors. |
| 3 | |
| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | you may not use this file except in compliance with the License. |
| 6 | You may obtain a copy of the License at |
| 7 | |
| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | |
| 10 | Unless required by applicable law or agreed to in writing, software |
| 11 | distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | See the License for the specific language governing permissions and |
| 14 | limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package generator |
| 18 | |
| 19 | import ( |
| 20 | "bytes" |
| 21 | "io" |
| 22 | |
| 23 | "k8s.io/gengo/namer" |
| 24 | "k8s.io/gengo/parser" |
| 25 | "k8s.io/gengo/types" |
| 26 | ) |
| 27 | |
| 28 | // Package contains the contract for generating a package. |
| 29 | type Package interface { |
| 30 | // Name returns the package short name. |
| 31 | Name() string |
| 32 | // Path returns the package import path. |
| 33 | Path() string |
| 34 | |
| 35 | // Filter should return true if this package cares about this type. |
| 36 | // Otherwise, this type will be omitted from the type ordering for |
| 37 | // this package. |
| 38 | Filter(*Context, *types.Type) bool |
| 39 | |
| 40 | // Header should return a header for the file, including comment markers. |
| 41 | // Useful for copyright notices and doc strings. Include an |
| 42 | // autogeneration notice! Do not include the "package x" line. |
| 43 | Header(filename string) []byte |
| 44 | |
| 45 | // Generators returns the list of generators for this package. It is |
| 46 | // allowed for more than one generator to write to the same file. |
| 47 | // A Context is passed in case the list of generators depends on the |
| 48 | // input types. |
| 49 | Generators(*Context) []Generator |
| 50 | } |
| 51 | |
| 52 | type File struct { |
| 53 | Name string |
| 54 | FileType string |
| 55 | PackageName string |
| 56 | Header []byte |
| 57 | Imports map[string]struct{} |
| 58 | Vars bytes.Buffer |
| 59 | Consts bytes.Buffer |
| 60 | Body bytes.Buffer |
| 61 | } |
| 62 | |
| 63 | type FileType interface { |
| 64 | AssembleFile(f *File, path string) error |
| 65 | VerifyFile(f *File, path string) error |
| 66 | } |
| 67 | |
| 68 | // Packages is a list of packages to generate. |
| 69 | type Packages []Package |
| 70 | |
| 71 | // Generator is the contract for anything that wants to do auto-generation. |
| 72 | // It's expected that the io.Writers passed to the below functions will be |
| 73 | // ErrorTrackers; this allows implementations to not check for io errors, |
| 74 | // making more readable code. |
| 75 | // |
| 76 | // The call order for the functions that take a Context is: |
| 77 | // 1. Filter() // Subsequent calls see only types that pass this. |
| 78 | // 2. Namers() // Subsequent calls see the namers provided by this. |
| 79 | // 3. PackageVars() |
| 80 | // 4. PackageConsts() |
| 81 | // 5. Init() |
| 82 | // 6. GenerateType() // Called N times, once per type in the context's Order. |
| 83 | // 7. Imports() |
| 84 | // |
| 85 | // You may have multiple generators for the same file. |
| 86 | type Generator interface { |
| 87 | // The name of this generator. Will be included in generated comments. |
| 88 | Name() string |
| 89 | |
| 90 | // Filter should return true if this generator cares about this type. |
| 91 | // (otherwise, GenerateType will not be called.) |
| 92 | // |
| 93 | // Filter is called before any of the generator's other functions; |
| 94 | // subsequent calls will get a context with only the types that passed |
| 95 | // this filter. |
| 96 | Filter(*Context, *types.Type) bool |
| 97 | |
| 98 | // If this generator needs special namers, return them here. These will |
| 99 | // override the original namers in the context if there is a collision. |
| 100 | // You may return nil if you don't need special names. These names will |
| 101 | // be available in the context passed to the rest of the generator's |
| 102 | // functions. |
| 103 | // |
| 104 | // A use case for this is to return a namer that tracks imports. |
| 105 | Namers(*Context) namer.NameSystems |
| 106 | |
| 107 | // Init should write an init function, and any other content that's not |
| 108 | // generated per-type. (It's not intended for generator specific |
| 109 | // initialization! Do that when your Package constructs the |
| 110 | // Generators.) |
| 111 | Init(*Context, io.Writer) error |
| 112 | |
| 113 | // Finalize should write finish up functions, and any other content that's not |
| 114 | // generated per-type. |
| 115 | Finalize(*Context, io.Writer) error |
| 116 | |
| 117 | // PackageVars should emit an array of variable lines. They will be |
| 118 | // placed in a var ( ... ) block. There's no need to include a leading |
| 119 | // \t or trailing \n. |
| 120 | PackageVars(*Context) []string |
| 121 | |
| 122 | // PackageConsts should emit an array of constant lines. They will be |
| 123 | // placed in a const ( ... ) block. There's no need to include a leading |
| 124 | // \t or trailing \n. |
| 125 | PackageConsts(*Context) []string |
| 126 | |
| 127 | // GenerateType should emit the code for a particular type. |
| 128 | GenerateType(*Context, *types.Type, io.Writer) error |
| 129 | |
| 130 | // Imports should return a list of necessary imports. They will be |
| 131 | // formatted correctly. You do not need to include quotation marks, |
| 132 | // return only the package name; alternatively, you can also return |
| 133 | // imports in the format `name "path/to/pkg"`. Imports will be called |
| 134 | // after Init, PackageVars, PackageConsts, and GenerateType, to allow |
| 135 | // you to keep track of what imports you actually need. |
| 136 | Imports(*Context) []string |
| 137 | |
| 138 | // Preferred file name of this generator, not including a path. It is |
| 139 | // allowed for multiple generators to use the same filename, but it's |
| 140 | // up to you to make sure they don't have colliding import names. |
| 141 | // TODO: provide per-file import tracking, removing the requirement |
| 142 | // that generators coordinate.. |
| 143 | Filename() string |
| 144 | |
| 145 | // A registered file type in the context to generate this file with. If |
| 146 | // the FileType is not found in the context, execution will stop. |
| 147 | FileType() string |
| 148 | } |
| 149 | |
| 150 | // Context is global context for individual generators to consume. |
| 151 | type Context struct { |
| 152 | // A map from the naming system to the names for that system. E.g., you |
| 153 | // might have public names and several private naming systems. |
| 154 | Namers namer.NameSystems |
| 155 | |
| 156 | // All the types, in case you want to look up something. |
| 157 | Universe types.Universe |
| 158 | |
| 159 | // All the user-specified packages. This is after recursive expansion. |
| 160 | Inputs []string |
| 161 | |
| 162 | // The canonical ordering of the types (will be filtered by both the |
| 163 | // Package's and Generator's Filter methods). |
| 164 | Order []*types.Type |
| 165 | |
| 166 | // A set of types this context can process. If this is empty or nil, |
| 167 | // the default "golang" filetype will be provided. |
| 168 | FileTypes map[string]FileType |
| 169 | |
| 170 | // If true, Execute* calls will just verify that the existing output is |
| 171 | // correct. (You may set this after calling NewContext.) |
| 172 | Verify bool |
| 173 | |
| 174 | // Allows generators to add packages at runtime. |
| 175 | builder *parser.Builder |
| 176 | } |
| 177 | |
| 178 | // NewContext generates a context from the given builder, naming systems, and |
| 179 | // the naming system you wish to construct the canonical ordering from. |
| 180 | func NewContext(b *parser.Builder, nameSystems namer.NameSystems, canonicalOrderName string) (*Context, error) { |
| 181 | universe, err := b.FindTypes() |
| 182 | if err != nil { |
| 183 | return nil, err |
| 184 | } |
| 185 | |
| 186 | c := &Context{ |
| 187 | Namers: namer.NameSystems{}, |
| 188 | Universe: universe, |
| 189 | Inputs: b.FindPackages(), |
| 190 | FileTypes: map[string]FileType{ |
| 191 | GolangFileType: NewGolangFile(), |
| 192 | }, |
| 193 | builder: b, |
| 194 | } |
| 195 | |
| 196 | for name, systemNamer := range nameSystems { |
| 197 | c.Namers[name] = systemNamer |
| 198 | if name == canonicalOrderName { |
| 199 | orderer := namer.Orderer{Namer: systemNamer} |
| 200 | c.Order = orderer.OrderUniverse(universe) |
| 201 | } |
| 202 | } |
| 203 | return c, nil |
| 204 | } |
| 205 | |
| 206 | // AddDir adds a Go package to the context. The specified path must be a single |
| 207 | // go package import path. GOPATH, GOROOT, and the location of your go binary |
| 208 | // (`which go`) will all be searched, in the normal Go fashion. |
| 209 | // Deprecated. Please use AddDirectory. |
| 210 | func (ctxt *Context) AddDir(path string) error { |
| 211 | return ctxt.builder.AddDirTo(path, &ctxt.Universe) |
| 212 | } |
| 213 | |
| 214 | // AddDirectory adds a Go package to the context. The specified path must be a |
| 215 | // single go package import path. GOPATH, GOROOT, and the location of your go |
| 216 | // binary (`which go`) will all be searched, in the normal Go fashion. |
| 217 | func (ctxt *Context) AddDirectory(path string) (*types.Package, error) { |
| 218 | return ctxt.builder.AddDirectoryTo(path, &ctxt.Universe) |
| 219 | } |