Different funcs for write and clear blob pages (Azure#28)

* Different funcs for write and clear blob pages

* Fixed tests, and changed a name for consistency

storage/pageblob.go

@@ -47,12 +47,28 @@ type PutPageOptions struct {
 	RequestID                         string     `header:"x-ms-client-request-id"`
 }
 
-// PutPage writes a range of pages to a page blob or clears the given range.
-// In case of 'clear' writes, given chunk is discarded. Ranges must be aligned
-// with 512-byte boundaries and chunk must be of size multiplies by 512.
+// WriteRange writes a range of pages to a page blob.
+// Ranges must be aligned with 512-byte boundaries and chunk must be of size
+// multiplies by 512.
 //
 // See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Put-Page
-func (b *Blob) PutPage(blobRange BlobRange, bytes io.Reader, options *PutPageOptions) error {
+func (b *Blob) WriteRange(blobRange BlobRange, bytes io.Reader, options *PutPageOptions) error {
+	if bytes == nil {
+		return errors.New("bytes cannot be nil")
+	}
+	return b.modifyRange(blobRange, bytes, options)
+}
+
+// ClearRange clears the given range in a page blob.
+// Ranges must be aligned with 512-byte boundaries and chunk must be of size
+// multiplies by 512.
+//
+// See https://docs.microsoft.com/en-us/rest/api/storageservices/fileservices/Put-Page
+func (b *Blob) ClearRange(blobRange BlobRange, options *PutPageOptions) error {
+	return b.modifyRange(blobRange, nil, options)
+}
+
+func (b *Blob) modifyRange(blobRange BlobRange, bytes io.Reader, options *PutPageOptions) error {
 	if blobRange.End < blobRange.Start {
 		return errors.New("the value for rangeEnd must be greater than or equal to rangeStart")
 	}

storage/pageblob_test.go

@@ -47,10 +47,10 @@ func (s *PageBlobSuite) TestPutPagesUpdate(c *chk.C) {
 	blobRange := BlobRange{
 		End: uint64(len(chunk1) - 1),
 	}
-	c.Assert(b.PutPage(blobRange, bytes.NewReader(chunk1), nil), chk.IsNil)
+	c.Assert(b.WriteRange(blobRange, bytes.NewReader(chunk1), nil), chk.IsNil)
 	blobRange.Start = uint64(len(chunk1))
 	blobRange.End = uint64(len(chunk1) + len(chunk2) - 1)
-	c.Assert(b.PutPage(blobRange, bytes.NewReader(chunk2), nil), chk.IsNil)
+	c.Assert(b.WriteRange(blobRange, bytes.NewReader(chunk2), nil), chk.IsNil)
 
 	// Verify contents
 	options := GetBlobRangeOptions{
@@ -69,7 +69,7 @@ func (s *PageBlobSuite) TestPutPagesUpdate(c *chk.C) {
 	chunk0 := []byte(randString(512))
 	blobRange.Start = 0
 	blobRange.End = uint64(len(chunk0) - 1)
-	c.Assert(b.PutPage(blobRange, bytes.NewReader(chunk0), nil), chk.IsNil)
+	c.Assert(b.WriteRange(blobRange, bytes.NewReader(chunk0), nil), chk.IsNil)
 
 	// Verify contents
 	out, err = b.GetRange(&options)
@@ -96,12 +96,12 @@ func (s *PageBlobSuite) TestPutPagesClear(c *chk.C) {
 	blobRange := BlobRange{
 		End: 2047,
 	}
-	c.Assert(b.PutPage(blobRange, bytes.NewReader(chunk), nil), chk.IsNil)
+	c.Assert(b.WriteRange(blobRange, bytes.NewReader(chunk), nil), chk.IsNil)
 
 	// Clear 512-1023
 	blobRange.Start = 512
 	blobRange.End = 1023
-	c.Assert(b.PutPage(blobRange, nil, nil), chk.IsNil)
+	c.Assert(b.ClearRange(blobRange, nil), chk.IsNil)
 
 	// Verify contents
 	options := GetBlobRangeOptions{
@@ -138,7 +138,7 @@ func (s *PageBlobSuite) TestGetPageRanges(c *chk.C) {
 	blobRange := BlobRange{
 		End: 511,
 	}
-	c.Assert(b.PutPage(blobRange, bytes.NewReader([]byte(randString(512))), nil), chk.IsNil)
+	c.Assert(b.WriteRange(blobRange, bytes.NewReader([]byte(randString(512))), nil), chk.IsNil)
 
 	out, err = b.GetPageRanges(nil)
 	c.Assert(err, chk.IsNil)
@@ -147,7 +147,7 @@ func (s *PageBlobSuite) TestGetPageRanges(c *chk.C) {
 	// Add 1024-2048
 	blobRange.Start = 1024
 	blobRange.End = 2047
-	c.Assert(b.PutPage(blobRange, bytes.NewReader([]byte(randString(1024))), nil), chk.IsNil)
+	c.Assert(b.WriteRange(blobRange, bytes.NewReader([]byte(randString(1024))), nil), chk.IsNil)
 
 	out, err = b.GetPageRanges(nil)
 	c.Assert(err, chk.IsNil)