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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/github.com/hpcloud/tail/watch/polling.go | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/github.com/hpcloud/tail/watch/polling.go')
-rw-r--r-- | vendor/github.com/hpcloud/tail/watch/polling.go | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/vendor/github.com/hpcloud/tail/watch/polling.go b/vendor/github.com/hpcloud/tail/watch/polling.go new file mode 100644 index 000000000..49491f21d --- /dev/null +++ b/vendor/github.com/hpcloud/tail/watch/polling.go @@ -0,0 +1,118 @@ +// Copyright (c) 2015 HPE Software Inc. All rights reserved. +// Copyright (c) 2013 ActiveState Software Inc. All rights reserved. + +package watch + +import ( + "os" + "runtime" + "time" + + "github.com/hpcloud/tail/util" + "gopkg.in/tomb.v1" +) + +// PollingFileWatcher polls the file for changes. +type PollingFileWatcher struct { + Filename string + Size int64 +} + +func NewPollingFileWatcher(filename string) *PollingFileWatcher { + fw := &PollingFileWatcher{filename, 0} + return fw +} + +var POLL_DURATION time.Duration + +func (fw *PollingFileWatcher) BlockUntilExists(t *tomb.Tomb) error { + for { + if _, err := os.Stat(fw.Filename); err == nil { + return nil + } else if !os.IsNotExist(err) { + return err + } + select { + case <-time.After(POLL_DURATION): + continue + case <-t.Dying(): + return tomb.ErrDying + } + } + panic("unreachable") +} + +func (fw *PollingFileWatcher) ChangeEvents(t *tomb.Tomb, pos int64) (*FileChanges, error) { + origFi, err := os.Stat(fw.Filename) + if err != nil { + return nil, err + } + + changes := NewFileChanges() + var prevModTime time.Time + + // XXX: use tomb.Tomb to cleanly manage these goroutines. replace + // the fatal (below) with tomb's Kill. + + fw.Size = pos + + go func() { + prevSize := fw.Size + for { + select { + case <-t.Dying(): + return + default: + } + + time.Sleep(POLL_DURATION) + fi, err := os.Stat(fw.Filename) + if err != nil { + // Windows cannot delete a file if a handle is still open (tail keeps one open) + // so it gives access denied to anything trying to read it until all handles are released. + if os.IsNotExist(err) || (runtime.GOOS == "windows" && os.IsPermission(err)) { + // File does not exist (has been deleted). + changes.NotifyDeleted() + return + } + + // XXX: report this error back to the user + util.Fatal("Failed to stat file %v: %v", fw.Filename, err) + } + + // File got moved/renamed? + if !os.SameFile(origFi, fi) { + changes.NotifyDeleted() + return + } + + // File got truncated? + fw.Size = fi.Size() + if prevSize > 0 && prevSize > fw.Size { + changes.NotifyTruncated() + prevSize = fw.Size + continue + } + // File got bigger? + if prevSize > 0 && prevSize < fw.Size { + changes.NotifyModified() + prevSize = fw.Size + continue + } + prevSize = fw.Size + + // File was appended to (changed)? + modTime := fi.ModTime() + if modTime != prevModTime { + prevModTime = modTime + changes.NotifyModified() + } + } + }() + + return changes, nil +} + +func init() { + POLL_DURATION = 250 * time.Millisecond +} |