| // Copyright 2018 The Wuffs 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 |
| // |
| // https://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 wuffsroot |
| |
| import ( |
| "errors" |
| "go/build" |
| "os" |
| "path/filepath" |
| "sync" |
| ) |
| |
| var cache struct { |
| mu sync.Mutex |
| value string |
| } |
| |
| func Value() (string, error) { |
| cache.mu.Lock() |
| value := cache.value |
| cache.mu.Unlock() |
| |
| if value != "" { |
| return value, nil |
| } |
| |
| // TODO: look for a WUFFSROOT environment variable? Also check that |
| // wuffs-root-directory.txt exists? |
| for _, p := range filepath.SplitList(build.Default.GOPATH) { |
| p = filepath.Join(p, "src", "github.com", "google", "wuffs") |
| if o, err := os.Stat(p); err == nil && o.IsDir() { |
| cache.mu.Lock() |
| cache.value = p |
| cache.mu.Unlock() |
| |
| return p, nil |
| } |
| } |
| return "", errors.New("could not find Wuffs root directory") |
| } |