testdriver.go

Documentation: github.com/docker/distribution/registry/storage/driver/testdriver

     1  package testdriver
     2  
     3  import (
     4  	"context"
     5  
     6  	storagedriver "github.com/docker/distribution/registry/storage/driver"
     7  	"github.com/docker/distribution/registry/storage/driver/factory"
     8  	"github.com/docker/distribution/registry/storage/driver/inmemory"
     9  )
    10  
    11  const driverName = "testdriver"
    12  
    13  func init() {
    14  	factory.Register(driverName, &testDriverFactory{})
    15  }
    16  
    17  // testDriverFactory implements the factory.StorageDriverFactory interface.
    18  type testDriverFactory struct{}
    19  
    20  func (factory *testDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
    21  	return New(), nil
    22  }
    23  
    24  // TestDriver is a StorageDriver for testing purposes. The Writer returned by this driver
    25  // simulates the case where Write operations are buffered. This causes the value returned by Size to lag
    26  // behind until Close (or Commit, or Cancel) is called.
    27  type TestDriver struct {
    28  	storagedriver.StorageDriver
    29  }
    30  
    31  type testFileWriter struct {
    32  	storagedriver.FileWriter
    33  	prevchunk []byte
    34  }
    35  
    36  var _ storagedriver.StorageDriver = &TestDriver{}
    37  
    38  // New constructs a new StorageDriver for testing purposes. The Writer returned by this driver
    39  // simulates the case where Write operations are buffered. This causes the value returned by Size to lag
    40  // behind until Close (or Commit, or Cancel) is called.
    41  func New() *TestDriver {
    42  	return &TestDriver{StorageDriver: inmemory.New()}
    43  }
    44  
    45  // Writer returns a FileWriter which will store the content written to it
    46  // at the location designated by "path" after the call to Commit.
    47  func (td *TestDriver) Writer(ctx context.Context, path string, append bool) (storagedriver.FileWriter, error) {
    48  	fw, err := td.StorageDriver.Writer(ctx, path, append)
    49  	return &testFileWriter{FileWriter: fw}, err
    50  }
    51  
    52  func (tfw *testFileWriter) Write(p []byte) (int, error) {
    53  	_, err := tfw.FileWriter.Write(tfw.prevchunk)
    54  	tfw.prevchunk = make([]byte, len(p))
    55  	copy(tfw.prevchunk, p)
    56  	return len(p), err
    57  }
    58  
    59  func (tfw *testFileWriter) Close() error {
    60  	tfw.Write(nil)
    61  	return tfw.FileWriter.Close()
    62  }
    63  
    64  func (tfw *testFileWriter) Cancel() error {
    65  	tfw.Write(nil)
    66  	return tfw.FileWriter.Cancel()
    67  }
    68  
    69  func (tfw *testFileWriter) Commit() error {
    70  	tfw.Write(nil)
    71  	return tfw.FileWriter.Commit()
    72  }
    73
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