| // Copyright (C) 2015 The Android Open Source Project |
| // |
| // 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 maker |
| |
| import ( |
| "log" |
| "regexp" |
| "time" |
| ) |
| |
| // Entity represents an object in the build graph. |
| type Entity interface { |
| // Name returns the unique name of this entity. |
| // If Name is the empty string, the entity does not appear in the main entity |
| // list and cannot be looked up. |
| Name() string |
| // Timestamp returns the last modified time of the entity, or the zero time if |
| // not available. |
| Timestamp() time.Time |
| // NeedsUpdate returns true if the entity requires it's generating step to run. |
| // The supplied timestamp is the newest timestamp of the entities this one |
| // depends on, and can be used to decide if an update is neccesary. |
| NeedsUpdate(t time.Time) bool |
| // Updated is called when a step that modifies this entity completes. |
| Updated() |
| } |
| |
| var ( |
| entities = map[string]Entity{} |
| entityHooks = []func(e Entity){} |
| ) |
| |
| // EntityHook registers a function that is invoked when a new entity is added |
| // to the system. |
| func EntityHook(f func(e Entity)) { |
| entityHooks = append(entityHooks, f) |
| } |
| |
| // FindEntity tries to look up an entity by name, and returns nil if the entity |
| // cannot be found. |
| func FindEntity(name string) Entity { |
| if name == "" { |
| return nil |
| } |
| e, _ := entities[name] |
| return e |
| } |
| |
| // FindPathEntity tries to look up an entity by name. |
| // If an exact match cannot be found, then the name is treated as a path, and |
| // the absolute path is looked up instead. |
| // If that also does not match, it returns nil. |
| func FindPathEntity(name string) Entity { |
| if e := FindEntity(name); e != nil { |
| return e |
| } |
| if abs, err := OSPath(name); err == nil { |
| if e := FindEntity(abs); e != nil { |
| return e |
| } |
| } |
| return nil |
| } |
| |
| // FindEntities tries to find all entities who's names match the supplied |
| // string. The string is treated as a case insensitive regular expression. |
| func FindEntities(pattern string) []Entity { |
| re := regexp.MustCompile("(?i)" + pattern) |
| matches := []Entity{} |
| for name, e := range entities { |
| if re.MatchString(name) { |
| matches = append(matches, e) |
| } |
| } |
| return matches |
| } |
| |
| // EntityOf tries to find an entity for the supplied value. |
| // If the value is an entity, it will be returned directly. If the value is a |
| // string it will use FindPathEntity to look it up. |
| // It is an error for v to not match an existing entity. |
| func EntityOf(v interface{}) Entity { |
| switch v := v.(type) { |
| case string: |
| e := FindPathEntity(v) |
| if e == nil { |
| log.Fatalf("no such entity %s", v) |
| } |
| return e |
| case Entity: |
| return v |
| default: |
| log.Fatalf("cannot get entity for %T", v) |
| return nil |
| } |
| } |
| |
| // AddEntity adds a new entity into the system. |
| // The entity must not have the same name as an already exixting entity. |
| func AddEntity(e Entity) { |
| name := e.Name() |
| if name != "" { |
| _, found := entities[name] |
| if found { |
| log.Fatalf("Attempt to remap entity name %s", name) |
| } |
| entities[name] = e |
| } |
| for _, h := range entityHooks { |
| h(e) |
| } |
| } |