cache.go

Documentation: github.com/go-openapi/spec

     1  // Copyright 2015 go-swagger maintainers
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //    http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package spec
    16  
    17  import (
    18  	"sync"
    19  )
    20  
    21  // ResolutionCache a cache for resolving urls
    22  type ResolutionCache interface {
    23  	Get(string) (interface{}, bool)
    24  	Set(string, interface{})
    25  }
    26  
    27  type simpleCache struct {
    28  	lock  sync.RWMutex
    29  	store map[string]interface{}
    30  }
    31  
    32  func (s *simpleCache) ShallowClone() ResolutionCache {
    33  	store := make(map[string]interface{}, len(s.store))
    34  	s.lock.RLock()
    35  	for k, v := range s.store {
    36  		store[k] = v
    37  	}
    38  	s.lock.RUnlock()
    39  
    40  	return &simpleCache{
    41  		store: store,
    42  	}
    43  }
    44  
    45  // Get retrieves a cached URI
    46  func (s *simpleCache) Get(uri string) (interface{}, bool) {
    47  	s.lock.RLock()
    48  	v, ok := s.store[uri]
    49  
    50  	s.lock.RUnlock()
    51  	return v, ok
    52  }
    53  
    54  // Set caches a URI
    55  func (s *simpleCache) Set(uri string, data interface{}) {
    56  	s.lock.Lock()
    57  	s.store[uri] = data
    58  	s.lock.Unlock()
    59  }
    60  
    61  var (
    62  	// resCache is a package level cache for $ref resolution and expansion.
    63  	// It is initialized lazily by methods that have the need for it: no
    64  	// memory is allocated unless some expander methods are called.
    65  	//
    66  	// It is initialized with JSON schema and swagger schema,
    67  	// which do not mutate during normal operations.
    68  	//
    69  	// All subsequent utilizations of this cache are produced from a shallow
    70  	// clone of this initial version.
    71  	resCache  *simpleCache
    72  	onceCache sync.Once
    73  
    74  	_ ResolutionCache = &simpleCache{}
    75  )
    76  
    77  // initResolutionCache initializes the URI resolution cache. To be wrapped in a sync.Once.Do call.
    78  func initResolutionCache() {
    79  	resCache = defaultResolutionCache()
    80  }
    81  
    82  func defaultResolutionCache() *simpleCache {
    83  	return &simpleCache{store: map[string]interface{}{
    84  		"http://swagger.io/v2/schema.json":       MustLoadSwagger20Schema(),
    85  		"http://json-schema.org/draft-04/schema": MustLoadJSONSchemaDraft04(),
    86  	}}
    87  }
    88  
    89  func cacheOrDefault(cache ResolutionCache) ResolutionCache {
    90  	onceCache.Do(initResolutionCache)
    91  
    92  	if cache != nil {
    93  		return cache
    94  	}
    95  
    96  	// get a shallow clone of the base cache with swagger and json schema
    97  	return resCache.ShallowClone()
    98  }
    99
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