diff options
Diffstat (limited to 'vendor/cloud.google.com/go/storage/reader.go')
| -rw-r--r-- | vendor/cloud.google.com/go/storage/reader.go | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/vendor/cloud.google.com/go/storage/reader.go b/vendor/cloud.google.com/go/storage/reader.go index 329a5f3..aa103c1 100644 --- a/vendor/cloud.google.com/go/storage/reader.go +++ b/vendor/cloud.google.com/go/storage/reader.go @@ -15,15 +15,22 @@ package storage import ( + "fmt" + "hash/crc32" "io" ) +var crc32cTable = crc32.MakeTable(crc32.Castagnoli) + // Reader reads a Cloud Storage object. // It implements io.Reader. type Reader struct { body io.ReadCloser remain, size int64 contentType string + checkCRC bool // should we check the CRC? + wantCRC uint32 // the CRC32c value the server sent in the header + gotCRC uint32 // running crc } // Close closes the Reader. It must be called when done reading. @@ -36,6 +43,16 @@ func (r *Reader) Read(p []byte) (int, error) { if r.remain != -1 { r.remain -= int64(n) } + if r.checkCRC { + r.gotCRC = crc32.Update(r.gotCRC, crc32cTable, p[:n]) + // Check CRC here. It would be natural to check it in Close, but + // everybody defers Close on the assumption that it doesn't return + // anything worth looking at. + if r.remain == 0 && r.gotCRC != r.wantCRC { + return n, fmt.Errorf("storage: bad CRC on read: got %d, want %d", + r.gotCRC, r.wantCRC) + } + } return n, err } |