| // Copyright 2018 The LUCI Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package graph |
| |
| import ( |
| "fmt" |
| "sort" |
| |
| "go.starlark.net/starlark" |
| ) |
| |
| // Graph is a DAG of keyed nodes. |
| // |
| // It implements starlark.HasAttrs interface and have the following methods: |
| // * key(typ1: string, id2: string, typ2: string, id2: string, ...): Key. |
| type Graph struct { |
| KeySet |
| } |
| |
| // String is a part of starlark.Value interface |
| func (g *Graph) String() string { return "graph" } |
| |
| // Type is a part of starlark.Value interface. |
| func (g *Graph) Type() string { return "graph" } |
| |
| // Freeze is a part of starlark.Value interface. |
| func (g *Graph) Freeze() {} |
| |
| // Truth is a part of starlark.Value interface. |
| func (g *Graph) Truth() starlark.Bool { return starlark.True } |
| |
| // Hash is a part of starlark.Value interface. |
| func (g *Graph) Hash() (uint32, error) { return 0, fmt.Errorf("unhashable") } |
| |
| // AttrNames is a part of starlark.HasAttrs interface. |
| func (g *Graph) AttrNames() []string { |
| names := make([]string, 0, len(graphAttrs)) |
| for k := range graphAttrs { |
| names = append(names, k) |
| } |
| sort.Strings(names) |
| return names |
| } |
| |
| // Attr is a part of starlark.HasAttrs interface. |
| func (g *Graph) Attr(name string) (starlark.Value, error) { |
| impl, ok := graphAttrs[name] |
| if !ok { |
| return nil, nil // per Attr(...) contract |
| } |
| return impl.BindReceiver(g), nil |
| } |
| |
| //// Starlark bindings for individual graph methods. |
| |
| var graphAttrs = map[string]*starlark.Builtin{ |
| "key": starlark.NewBuiltin("key", func(_ *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) { |
| if len(kwargs) != 0 { |
| return nil, fmt.Errorf("graph.key: not expecting keyword arguments") |
| } |
| pairs := make([]string, len(args)) |
| for idx, arg := range args { |
| str, ok := arg.(starlark.String) |
| if !ok { |
| return nil, fmt.Errorf("graph.key: all arguments must be strings, arg #%d was %s", idx, arg.Type()) |
| } |
| pairs[idx] = str.GoString() |
| } |
| return b.Receiver().(*Graph).Key(pairs...) |
| }), |
| } |