/* # Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved. # # 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 lookup import ( "errors" "fmt" "os" "path/filepath" "github.com/NVIDIA/nvidia-container-toolkit/internal/logger" ) // ErrNotFound indicates that a specified pattern or file could not be found. var ErrNotFound = errors.New("not found") // file can be used to locate file (or file-like elements) at a specified set of // prefixes. The validity of a file is determined by a filter function. type file struct { builder prefixes []string } // builder defines the builder for a file locator. type builder struct { logger logger.Interface root string searchPaths []string filter func(string) error count int isOptional bool } // Option defines a function for passing builder to the NewFileLocator() call type Option func(*builder) // WithRoot sets the root for the file locator func WithRoot(root string) Option { return func(f *builder) { f.root = root } } // WithLogger sets the logger for the file locator func WithLogger(logger logger.Interface) Option { return func(f *builder) { f.logger = logger } } // WithSearchPaths sets the search paths for the file locator. func WithSearchPaths(paths ...string) Option { return func(f *builder) { f.searchPaths = paths } } // WithFilter sets the filter for the file locator // The filter is called for each candidate file and candidates that return nil are considered. func WithFilter(assert func(string) error) Option { return func(f *builder) { f.filter = assert } } // WithCount sets the maximum number of candidates to discover func WithCount(count int) Option { return func(f *builder) { f.count = count } } // WithOptional sets the optional flag for the file locator // If the optional flag is set, the locator will not return an error if the file is not found. func WithOptional(optional bool) Option { return func(f *builder) { f.isOptional = optional } } func newBuilder(opts ...Option) *builder { o := &builder{} for _, opt := range opts { opt(o) } if o.logger == nil { o.logger = logger.New() } if o.filter == nil { o.filter = assertFile } return o } func (o builder) build() *file { f := file{ builder: o, // Since the `Locate` implementations rely on the root already being specified we update // the prefixes to include the root. prefixes: getSearchPrefixes(o.root, o.searchPaths...), } return &f } // NewFileLocator creates a Locator that can be used to find files with the specified builder. func NewFileLocator(opts ...Option) Locator { return newFileLocator(opts...) } func newFileLocator(opts ...Option) *file { return newBuilder(opts...).build() } // getSearchPrefixes generates a list of unique paths to be searched by a file locator. // // For each of the unique prefixes
specified, the path is searched, where