diff options
Diffstat (limited to 'vendor/github.com/aws/aws-sdk-go/aws/types.go')
-rw-r--r-- | vendor/github.com/aws/aws-sdk-go/aws/types.go | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/vendor/github.com/aws/aws-sdk-go/aws/types.go b/vendor/github.com/aws/aws-sdk-go/aws/types.go index 0e2d864..8b6f234 100644 --- a/vendor/github.com/aws/aws-sdk-go/aws/types.go +++ b/vendor/github.com/aws/aws-sdk-go/aws/types.go @@ -3,6 +3,8 @@ package aws import ( "io" "sync" + + "github.com/aws/aws-sdk-go/internal/sdkio" ) // ReadSeekCloser wraps a io.Reader returning a ReaderSeekerCloser. Should @@ -22,6 +24,22 @@ type ReaderSeekerCloser struct { r io.Reader } +// IsReaderSeekable returns if the underlying reader type can be seeked. A +// io.Reader might not actually be seekable if it is the ReaderSeekerCloser +// type. +func IsReaderSeekable(r io.Reader) bool { + switch v := r.(type) { + case ReaderSeekerCloser: + return v.IsSeeker() + case *ReaderSeekerCloser: + return v.IsSeeker() + case io.ReadSeeker: + return true + default: + return false + } +} + // Read reads from the reader up to size of p. The number of bytes read, and // error if it occurred will be returned. // @@ -56,6 +74,71 @@ func (r ReaderSeekerCloser) IsSeeker() bool { return ok } +// HasLen returns the length of the underlying reader if the value implements +// the Len() int method. +func (r ReaderSeekerCloser) HasLen() (int, bool) { + type lenner interface { + Len() int + } + + if lr, ok := r.r.(lenner); ok { + return lr.Len(), true + } + + return 0, false +} + +// GetLen returns the length of the bytes remaining in the underlying reader. +// Checks first for Len(), then io.Seeker to determine the size of the +// underlying reader. +// +// Will return -1 if the length cannot be determined. +func (r ReaderSeekerCloser) GetLen() (int64, error) { + if l, ok := r.HasLen(); ok { + return int64(l), nil + } + + if s, ok := r.r.(io.Seeker); ok { + return seekerLen(s) + } + + return -1, nil +} + +// SeekerLen attempts to get the number of bytes remaining at the seeker's +// current position. Returns the number of bytes remaining or error. +func SeekerLen(s io.Seeker) (int64, error) { + // Determine if the seeker is actually seekable. ReaderSeekerCloser + // hides the fact that a io.Readers might not actually be seekable. + switch v := s.(type) { + case ReaderSeekerCloser: + return v.GetLen() + case *ReaderSeekerCloser: + return v.GetLen() + } + + return seekerLen(s) +} + +func seekerLen(s io.Seeker) (int64, error) { + curOffset, err := s.Seek(0, sdkio.SeekCurrent) + if err != nil { + return 0, err + } + + endOffset, err := s.Seek(0, sdkio.SeekEnd) + if err != nil { + return 0, err + } + + _, err = s.Seek(curOffset, sdkio.SeekStart) + if err != nil { + return 0, err + } + + return endOffset - curOffset, nil +} + // Close closes the ReaderSeekerCloser. // // If the ReaderSeekerCloser is not an io.Closer nothing will be done. |