github.com/dolthub/dolt/go@v0.40.5-0.20240520175717-68db7794bea6/store/util/tempfiles/temp_files.go (about)

     1  // Copyright 2020 Dolthub, Inc.
     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 tempfiles
    16  
    17  import (
    18  	"os"
    19  	"sync"
    20  
    21  	"github.com/dolthub/dolt/go/libraries/utils/file"
    22  )
    23  
    24  // TempFileProvider is an interface which provides methods for creating temporary files.
    25  type TempFileProvider interface {
    26  	// GetTempDir returns the directory where temp files will be created by default
    27  	GetTempDir() string
    28  
    29  	// NewFile creates a new temporary file in the directory dir, opens the file for reading and writing, and returns
    30  	// the resulting *os.File. If dir is "" then the default temp dir is used.
    31  	NewFile(dir, pattern string) (*os.File, error)
    32  
    33  	// Clean makes a best effort attempt to delete all temp files created by calls to NewFile
    34  	Clean()
    35  }
    36  
    37  // TempFileProviderAt is a TempFileProvider interface which creates temp files at a given path.
    38  type TempFileProviderAt struct {
    39  	tempDir      string
    40  	filesCreated []string
    41  	mu           sync.Mutex
    42  }
    43  
    44  // NewTempFileProviderAt creates a new TempFileProviderAt instance with the provided directory to create files in. The
    45  // directory is assumed to have been created already.
    46  func NewTempFileProviderAt(tempDir string) *TempFileProviderAt {
    47  	return &TempFileProviderAt{tempDir, nil, sync.Mutex{}}
    48  }
    49  
    50  // GetTempDir returns the directory where temp files will be created by default
    51  func (tfp *TempFileProviderAt) GetTempDir() string {
    52  	return tfp.tempDir
    53  }
    54  
    55  // NewFile creates a new temporary file in the directory dir, opens the file for reading and writing, and returns
    56  // the resulting *os.File. If dir is "" then the default temp dir is used.
    57  func (tfp *TempFileProviderAt) NewFile(dir, pattern string) (*os.File, error) {
    58  	tfp.mu.Lock()
    59  	defer tfp.mu.Unlock()
    60  	if dir == "" {
    61  		dir = tfp.tempDir
    62  	}
    63  
    64  	f, err := os.CreateTemp(dir, pattern)
    65  
    66  	if err == nil {
    67  		tfp.filesCreated = append(tfp.filesCreated, f.Name())
    68  	}
    69  
    70  	return f, err
    71  }
    72  
    73  // Clean makes a best effort attempt to delete all temp files created by calls to NewFile
    74  func (tfp *TempFileProviderAt) Clean() {
    75  	tfp.mu.Lock()
    76  	defer tfp.mu.Unlock()
    77  	for _, filename := range tfp.filesCreated {
    78  		// best effort. ignore errors
    79  		_ = file.Remove(filename)
    80  	}
    81  }
    82  
    83  // MovableTemFile is an object that implements TempFileProvider that is used by the nbs to create temp files that
    84  // ultimately will be renamed.  It is important to use this instance rather than using os.TempDir, or os.CreateTemp
    85  // directly as those may have errors executing a rename against if the volume the default temporary directory lives on
    86  // is different than the volume of the destination of the rename.
    87  var MovableTempFileProvider TempFileProvider = NewTempFileProviderAt(os.TempDir())