diff options
Diffstat (limited to 'vendor/github.com/rjeczalik/notify/tree_recursive.go')
-rw-r--r-- | vendor/github.com/rjeczalik/notify/tree_recursive.go | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/vendor/github.com/rjeczalik/notify/tree_recursive.go b/vendor/github.com/rjeczalik/notify/tree_recursive.go new file mode 100644 index 000000000..7f00dfe35 --- /dev/null +++ b/vendor/github.com/rjeczalik/notify/tree_recursive.go @@ -0,0 +1,354 @@ +// Copyright (c) 2014-2015 The Notify Authors. All rights reserved. +// Use of this source code is governed by the MIT license that can be +// found in the LICENSE file. + +package notify + +import "sync" + +// watchAdd TODO(rjeczalik) +func watchAdd(nd node, c chan<- EventInfo, e Event) eventDiff { + diff := nd.Watch.Add(c, e) + if wp := nd.Child[""].Watch; len(wp) != 0 { + e = wp.Total() + diff[0] |= e + diff[1] |= e + if diff[0] == diff[1] { + return none + } + } + return diff +} + +// watchAddInactive TODO(rjeczalik) +func watchAddInactive(nd node, c chan<- EventInfo, e Event) eventDiff { + wp := nd.Child[""].Watch + if wp == nil { + wp = make(watchpoint) + nd.Child[""] = node{Watch: wp} + } + diff := wp.Add(c, e) + e = nd.Watch.Total() + diff[0] |= e + diff[1] |= e + if diff[0] == diff[1] { + return none + } + return diff +} + +// watchCopy TODO(rjeczalik) +func watchCopy(src, dst node) { + for c, e := range src.Watch { + if c == nil { + continue + } + watchAddInactive(dst, c, e) + } + if wpsrc := src.Child[""].Watch; len(wpsrc) != 0 { + wpdst := dst.Child[""].Watch + for c, e := range wpsrc { + if c == nil { + continue + } + wpdst.Add(c, e) + } + } +} + +// watchDel TODO(rjeczalik) +func watchDel(nd node, c chan<- EventInfo, e Event) eventDiff { + diff := nd.Watch.Del(c, e) + if wp := nd.Child[""].Watch; len(wp) != 0 { + diffInactive := wp.Del(c, e) + e = wp.Total() + // TODO(rjeczalik): add e if e != all? + diff[0] |= diffInactive[0] | e + diff[1] |= diffInactive[1] | e + if diff[0] == diff[1] { + return none + } + } + return diff +} + +// watchTotal TODO(rjeczalik) +func watchTotal(nd node) Event { + e := nd.Watch.Total() + if wp := nd.Child[""].Watch; len(wp) != 0 { + e |= wp.Total() + } + return e +} + +// watchIsRecursive TODO(rjeczalik) +func watchIsRecursive(nd node) bool { + ok := nd.Watch.IsRecursive() + // TODO(rjeczalik): add a test for len(wp) != 0 change the condition. + if wp := nd.Child[""].Watch; len(wp) != 0 { + // If a watchpoint holds inactive watchpoints, it means it's a parent + // one, which is recursive by nature even though it may be not recursive + // itself. + ok = true + } + return ok +} + +// recursiveTree TODO(rjeczalik) +type recursiveTree struct { + rw sync.RWMutex // protects root + root root + // TODO(rjeczalik): merge watcher + recursiveWatcher after #5 and #6 + w interface { + watcher + recursiveWatcher + } + c chan EventInfo +} + +// newRecursiveTree TODO(rjeczalik) +func newRecursiveTree(w recursiveWatcher, c chan EventInfo) *recursiveTree { + t := &recursiveTree{ + root: root{nd: newnode("")}, + w: struct { + watcher + recursiveWatcher + }{w.(watcher), w}, + c: c, + } + go t.dispatch() + return t +} + +// dispatch TODO(rjeczalik) +func (t *recursiveTree) dispatch() { + for ei := range t.c { + dbgprintf("dispatching %v on %q", ei.Event(), ei.Path()) + go func(ei EventInfo) { + nd, ok := node{}, false + dir, base := split(ei.Path()) + fn := func(it node, isbase bool) error { + if isbase { + nd = it + } else { + it.Watch.Dispatch(ei, recursive) + } + return nil + } + t.rw.RLock() + defer t.rw.RUnlock() + // Notify recursive watchpoints found on the path. + if err := t.root.WalkPath(dir, fn); err != nil { + dbgprint("dispatch did not reach leaf:", err) + return + } + // Notify parent watchpoint. + nd.Watch.Dispatch(ei, 0) + // If leaf watchpoint exists, notify it. + if nd, ok = nd.Child[base]; ok { + nd.Watch.Dispatch(ei, 0) + } + }(ei) + } +} + +// Watch TODO(rjeczalik) +func (t *recursiveTree) Watch(path string, c chan<- EventInfo, events ...Event) error { + if c == nil { + panic("notify: Watch using nil channel") + } + // Expanding with empty event set is a nop. + if len(events) == 0 { + return nil + } + path, isrec, err := cleanpath(path) + if err != nil { + return err + } + eventset := joinevents(events) + if isrec { + eventset |= recursive + } + t.rw.Lock() + defer t.rw.Unlock() + // case 1: cur is a child + // + // Look for parent watch which already covers the given path. + parent := node{} + self := false + err = t.root.WalkPath(path, func(nd node, isbase bool) error { + if watchTotal(nd) != 0 { + parent = nd + self = isbase + return errSkip + } + return nil + }) + cur := t.root.Add(path) // add after the walk, so it's less to traverse + if err == nil && parent.Watch != nil { + // Parent watch found. Register inactive watchpoint, so we have enough + // information to shrink the eventset on eventual Stop. + // return t.resetwatchpoint(parent, parent, c, eventset|inactive) + var diff eventDiff + if self { + diff = watchAdd(cur, c, eventset) + } else { + diff = watchAddInactive(parent, c, eventset) + } + switch { + case diff == none: + // the parent watchpoint already covers requested subtree with its + // eventset + case diff[0] == 0: + // TODO(rjeczalik): cleanup this panic after implementation is stable + panic("dangling watchpoint: " + parent.Name) + default: + if isrec || watchIsRecursive(parent) { + err = t.w.RecursiveRewatch(parent.Name, parent.Name, diff[0], diff[1]) + } else { + err = t.w.Rewatch(parent.Name, diff[0], diff[1]) + } + if err != nil { + watchDel(parent, c, diff.Event()) + return err + } + watchAdd(cur, c, eventset) + // TODO(rjeczalik): account top-most path for c + return nil + } + if !self { + watchAdd(cur, c, eventset) + } + return nil + } + // case 2: cur is new parent + // + // Look for children nodes, unwatch n-1 of them and rewatch the last one. + var children []node + fn := func(nd node) error { + if len(nd.Watch) == 0 { + return nil + } + children = append(children, nd) + return errSkip + } + switch must(cur.Walk(fn)); len(children) { + case 0: + // no child watches, cur holds a new watch + case 1: + watchAdd(cur, c, eventset) // TODO(rjeczalik): update cache c subtree root? + watchCopy(children[0], cur) + err = t.w.RecursiveRewatch(children[0].Name, cur.Name, watchTotal(children[0]), + watchTotal(cur)) + if err != nil { + // Clean inactive watchpoint. The c chan did not exist before. + cur.Child[""] = node{} + delete(cur.Watch, c) + return err + } + return nil + default: + watchAdd(cur, c, eventset) + // Copy children inactive watchpoints to the new parent. + for _, nd := range children { + watchCopy(nd, cur) + } + // Watch parent subtree. + if err = t.w.RecursiveWatch(cur.Name, watchTotal(cur)); err != nil { + // Clean inactive watchpoint. The c chan did not exist before. + cur.Child[""] = node{} + delete(cur.Watch, c) + return err + } + // Unwatch children subtrees. + var e error + for _, nd := range children { + if watchIsRecursive(nd) { + e = t.w.RecursiveUnwatch(nd.Name) + } else { + e = t.w.Unwatch(nd.Name) + } + if e != nil { + err = nonil(err, e) + // TODO(rjeczalik): child is still watched, warn all its watchpoints + // about possible duplicate events via Error event + } + } + return err + } + // case 3: cur is new, alone node + switch diff := watchAdd(cur, c, eventset); { + case diff == none: + // TODO(rjeczalik): cleanup this panic after implementation is stable + panic("watch requested but no parent watchpoint found: " + cur.Name) + case diff[0] == 0: + if isrec { + err = t.w.RecursiveWatch(cur.Name, diff[1]) + } else { + err = t.w.Watch(cur.Name, diff[1]) + } + if err != nil { + watchDel(cur, c, diff.Event()) + return err + } + default: + // TODO(rjeczalik): cleanup this panic after implementation is stable + panic("watch requested but no parent watchpoint found: " + cur.Name) + } + return nil +} + +// Stop TODO(rjeczalik) +// +// TODO(rjeczalik): Split parent watchpoint - transfer watches to children +// if parent is no longer needed. This carries a risk that underlying +// watcher calls could fail - reconsider if it's worth the effort. +func (t *recursiveTree) Stop(c chan<- EventInfo) { + var err error + fn := func(nd node) (e error) { + diff := watchDel(nd, c, all) + switch { + case diff == none && watchTotal(nd) == 0: + // TODO(rjeczalik): There's no watchpoints deeper in the tree, + // probably we should remove the nodes as well. + return nil + case diff == none: + // Removing c from nd does not require shrinking its eventset. + case diff[1] == 0: + if watchIsRecursive(nd) { + e = t.w.RecursiveUnwatch(nd.Name) + } else { + e = t.w.Unwatch(nd.Name) + } + default: + if watchIsRecursive(nd) { + e = t.w.RecursiveRewatch(nd.Name, nd.Name, diff[0], diff[1]) + } else { + e = t.w.Rewatch(nd.Name, diff[0], diff[1]) + } + } + fn := func(nd node) error { + watchDel(nd, c, all) + return nil + } + err = nonil(err, e, nd.Walk(fn)) + // TODO(rjeczalik): if e != nil store dummy chan in nd.Watch just to + // retry un/rewatching next time and/or let the user handle the failure + // vie Error event? + return errSkip + } + t.rw.Lock() + e := t.root.Walk("", fn) // TODO(rjeczalik): use max root per c + t.rw.Unlock() + if e != nil { + err = nonil(err, e) + } + dbgprintf("Stop(%p) error: %v\n", c, err) +} + +// Close TODO(rjeczalik) +func (t *recursiveTree) Close() error { + err := t.w.Close() + close(t.c) + return err +} |