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Check the MD5SUM of an object if the mtime is different before uploading

This commit is contained in:
Nick Craig-Wood 2012-11-28 17:24:00 +00:00
parent 5ebbe342b8
commit dbb039af9f
1 changed files with 34 additions and 20 deletions
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54
swiftsync.go
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@ -65,12 +65,20 @@ func (fs *FsObject) md5sum() (string, error) {
return fmt.Sprintf("%x", hash.Sum(nil)), nil
}
// Checks to see if an object has changed or not by looking at its size and mtime
// Checks to see if an object has changed or not by looking at its size, mtime and MD5SUM
//
// This is the heuristic rsync uses when not using --checksum
// If the remote object size is different then it is considered to be
// changed.
//
// If the remote object doesn't have the mtime metadata set then the
// checksum is checked
// If the size is the same and the mtime is the same then it is
// considered to be unchanged. This is the heuristic rsync uses when
// not using --checksum.
//
// If the size is the same and and mtime is different or unreadable
// and the MD5SUM is the same then the file is considered to be
// unchanged.
//
// Otherwise the file is considered to be changed.
//
// FIXME should update the checksum of the remote object with the mtime
func (fs *FsObject) changed(c *swift.Connection, container string) bool {
@ -83,29 +91,35 @@ func (fs *FsObject) changed(c *swift.Connection, container string) bool {
fs.Debugf("Sizes differ")
return true
}
// Size the same so check the mtime
m := h.ObjectMetadata()
t, err := m.GetModTime()
if err != nil {
fs.Debugf("Failed to read mtime: %s", err)
localMd5, err := fs.md5sum()
// fs.Debugf("Local MD5 %s", localMd5)
// fs.Debugf("Remote MD5 %s", obj.Hash)
if err != nil {
fs.Debugf("Failed to calculate md5: %s", err)
return true
}
if localMd5 != strings.ToLower(obj.Hash) {
fs.Debugf("Md5sums differ")
return true
}
fs.Debugf("Md5sums identical - skipping")
// FIXME update the mtime of the remote object here
return false
}
if !t.Equal(fs.info.ModTime()) {
} else if !t.Equal(fs.info.ModTime()) {
fs.Debugf("Modification times differ")
} else {
fs.Debugf("Size and modification time the same - skipping")
return false
}
// mtime is unreadable or different but size is the same so
// check the MD5SUM
localMd5, err := fs.md5sum()
if err != nil {
fs.Debugf("Failed to calculate md5: %s", err)
return true
}
// fs.Debugf("Local MD5 %s", localMd5)
// fs.Debugf("Remote MD5 %s", obj.Hash)
if localMd5 != strings.ToLower(obj.Hash) {
fs.Debugf("Md5sums differ")
return true
}
// FIXME update the mtime of the remote object here
fs.Debugf("Size and MD5SUM identical - skipping")
return false
}