github.com/cs3org/reva/v2@v2.27.7/pkg/publicshare/manager/json/persistence/file/file.go (about)

     1  // Copyright 2018-2021 CERN
     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  // In applying this license, CERN does not waive the privileges and immunities
    16  // granted to it by virtue of its status as an Intergovernmental Organization
    17  // or submit itself to any jurisdiction.
    18  
    19  package file
    20  
    21  import (
    22  	"context"
    23  	"encoding/json"
    24  	"fmt"
    25  	"os"
    26  	"path/filepath"
    27  	"sync"
    28  
    29  	"github.com/cs3org/reva/v2/pkg/publicshare/manager/json/persistence"
    30  )
    31  
    32  type file struct {
    33  	path        string
    34  	initialized bool
    35  	lock        *sync.RWMutex
    36  }
    37  
    38  // New returns a new Cache instance
    39  func New(path string) persistence.Persistence {
    40  	return &file{
    41  		path: path,
    42  		lock: &sync.RWMutex{},
    43  	}
    44  }
    45  
    46  func (p *file) Init(_ context.Context) error {
    47  	if p.isInitialized() {
    48  		return nil
    49  	}
    50  
    51  	p.lock.Lock()
    52  	defer p.lock.Unlock()
    53  	if p.initialized {
    54  		return nil
    55  	}
    56  
    57  	// attempt to create the db file
    58  	var fi os.FileInfo
    59  	var err error
    60  	if fi, err = os.Stat(p.path); os.IsNotExist(err) {
    61  		folder := filepath.Dir(p.path)
    62  		if err := os.MkdirAll(folder, 0755); err != nil {
    63  			return err
    64  		}
    65  		if _, err := os.Create(p.path); err != nil {
    66  			return err
    67  		}
    68  	}
    69  
    70  	if fi == nil || fi.Size() == 0 {
    71  		err := os.WriteFile(p.path, []byte("{}"), 0644)
    72  		if err != nil {
    73  			return err
    74  		}
    75  	}
    76  	p.initialized = true
    77  	return nil
    78  }
    79  
    80  func (p *file) Read(_ context.Context) (persistence.PublicShares, error) {
    81  	if !p.isInitialized() {
    82  		return nil, fmt.Errorf("not initialized")
    83  	}
    84  	db := map[string]interface{}{}
    85  	readBytes, err := os.ReadFile(p.path)
    86  	if err != nil {
    87  		return nil, err
    88  	}
    89  	if err := json.Unmarshal(readBytes, &db); err != nil {
    90  		return nil, err
    91  	}
    92  	return db, nil
    93  }
    94  
    95  func (p *file) Write(_ context.Context, db persistence.PublicShares) error {
    96  	if !p.isInitialized() {
    97  		return fmt.Errorf("not initialized")
    98  	}
    99  	dbAsJSON, err := json.Marshal(db)
   100  	if err != nil {
   101  		return err
   102  	}
   103  
   104  	return os.WriteFile(p.path, dbAsJSON, 0644)
   105  }
   106  
   107  func (p *file) isInitialized() bool {
   108  	p.lock.RLock()
   109  	defer p.lock.RUnlock()
   110  	return p.initialized
   111  }