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author | Péter Szilágyi <peterke@gmail.com> | 2016-10-29 01:05:01 +0800 |
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committer | Felix Lange <fjl@twurst.com> | 2016-10-29 01:05:01 +0800 |
commit | 289b30715d097edafd5562f66cb3567a70b2d330 (patch) | |
tree | 7eaaa6da97c84727469303b986e364606ece57ce /vendor/github.com/rjeczalik/notify/watcher_readdcw.go | |
parent | 77703045765343c489ded2f43e3ed0f332c5f148 (diff) | |
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Godeps, vendor: convert dependency management to trash (#3198)
This commit converts the dependency management from Godeps to the vendor
folder, also switching the tool from godep to trash. Since the upstream tool
lacks a few features proposed via a few PRs, until those PRs are merged in
(if), use github.com/karalabe/trash.
You can update dependencies via trash --update.
All dependencies have been updated to their latest version.
Parts of the build system are reworked to drop old notions of Godeps and
invocation of the go vet command so that it doesn't run against the vendor
folder, as that will just blow up during vetting.
The conversion drops OpenCL (and hence GPU mining support) from ethash and our
codebase. The short reasoning is that there's noone to maintain and having
opencl libs in our deps messes up builds as go install ./... tries to build
them, failing with unsatisfied link errors for the C OpenCL deps.
golang.org/x/net/context is not vendored in. We expect it to be fetched by the
user (i.e. using go get). To keep ci.go builds reproducible the package is
"vendored" in build/_vendor.
Diffstat (limited to 'vendor/github.com/rjeczalik/notify/watcher_readdcw.go')
-rw-r--r-- | vendor/github.com/rjeczalik/notify/watcher_readdcw.go | 574 |
1 files changed, 574 insertions, 0 deletions
diff --git a/vendor/github.com/rjeczalik/notify/watcher_readdcw.go b/vendor/github.com/rjeczalik/notify/watcher_readdcw.go new file mode 100644 index 000000000..5923bfdda --- /dev/null +++ b/vendor/github.com/rjeczalik/notify/watcher_readdcw.go @@ -0,0 +1,574 @@ +// 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. + +// +build windows + +package notify + +import ( + "errors" + "runtime" + "sync" + "sync/atomic" + "syscall" + "unsafe" +) + +// readBufferSize defines the size of an array in which read statuses are stored. +// The buffer have to be DWORD-aligned and, if notify is used in monitoring a +// directory over the network, its size must not be greater than 64KB. Each of +// watched directories uses its own buffer for storing events. +const readBufferSize = 4096 + +// Since all operations which go through the Windows completion routine are done +// asynchronously, filter may set one of the constants belor. They were defined +// in order to distinguish whether current folder should be re-registered in +// ReadDirectoryChangesW function or some control operations need to be executed. +const ( + stateRewatch uint32 = 1 << (28 + iota) + stateUnwatch + stateCPClose +) + +// Filter used in current implementation was split into four segments: +// - bits 0-11 store ReadDirectoryChangesW filters, +// - bits 12-19 store File notify actions, +// - bits 20-27 store notify specific events and flags, +// - bits 28-31 store states which are used in loop's FSM. +// Constants below are used as masks to retrieve only specific filter parts. +const ( + onlyNotifyChanges uint32 = 0x00000FFF + onlyNGlobalEvents uint32 = 0x0FF00000 + onlyMachineStates uint32 = 0xF0000000 +) + +// grip represents a single watched directory. It stores the data required by +// ReadDirectoryChangesW function. Only the filter, recursive, and handle members +// may by modified by watcher implementation. Rest of the them have to remain +// constant since they are used by Windows completion routine. This indicates that +// grip can be removed only when all operations on the file handle are finished. +type grip struct { + handle syscall.Handle + filter uint32 + recursive bool + pathw []uint16 + buffer [readBufferSize]byte + parent *watched + ovlapped *overlappedEx +} + +// overlappedEx stores information used in asynchronous input and output. +// Additionally, overlappedEx contains a pointer to 'grip' item which is used in +// order to gather the structure in which the overlappedEx object was created. +type overlappedEx struct { + syscall.Overlapped + parent *grip +} + +// newGrip creates a new file handle that can be used in overlapped operations. +// Then, the handle is associated with I/O completion port 'cph' and its value +// is stored in newly created 'grip' object. +func newGrip(cph syscall.Handle, parent *watched, filter uint32) (*grip, error) { + g := &grip{ + handle: syscall.InvalidHandle, + filter: filter, + recursive: parent.recursive, + pathw: parent.pathw, + parent: parent, + ovlapped: &overlappedEx{}, + } + if err := g.register(cph); err != nil { + return nil, err + } + g.ovlapped.parent = g + return g, nil +} + +// NOTE : Thread safe +func (g *grip) register(cph syscall.Handle) (err error) { + if g.handle, err = syscall.CreateFile( + &g.pathw[0], + syscall.FILE_LIST_DIRECTORY, + syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE, + nil, + syscall.OPEN_EXISTING, + syscall.FILE_FLAG_BACKUP_SEMANTICS|syscall.FILE_FLAG_OVERLAPPED, + 0, + ); err != nil { + return + } + if _, err = syscall.CreateIoCompletionPort(g.handle, cph, 0, 0); err != nil { + syscall.CloseHandle(g.handle) + return + } + return g.readDirChanges() +} + +// readDirChanges tells the system to store file change information in grip's +// buffer. Directory changes that occur between calls to this function are added +// to the buffer and then, returned with the next call. +func (g *grip) readDirChanges() error { + return syscall.ReadDirectoryChanges( + g.handle, + &g.buffer[0], + uint32(unsafe.Sizeof(g.buffer)), + g.recursive, + encode(g.filter), + nil, + (*syscall.Overlapped)(unsafe.Pointer(g.ovlapped)), + 0, + ) +} + +// encode transforms a generic filter, which contains platform independent and +// implementation specific bit fields, to value that can be used as NotifyFilter +// parameter in ReadDirectoryChangesW function. +func encode(filter uint32) uint32 { + e := Event(filter & (onlyNGlobalEvents | onlyNotifyChanges)) + if e&dirmarker != 0 { + return uint32(FileNotifyChangeDirName) + } + if e&Create != 0 { + e = (e ^ Create) | FileNotifyChangeFileName + } + if e&Remove != 0 { + e = (e ^ Remove) | FileNotifyChangeFileName + } + if e&Write != 0 { + e = (e ^ Write) | FileNotifyChangeAttributes | FileNotifyChangeSize | + FileNotifyChangeCreation | FileNotifyChangeSecurity + } + if e&Rename != 0 { + e = (e ^ Rename) | FileNotifyChangeFileName + } + return uint32(e) +} + +// watched is made in order to check whether an action comes from a directory or +// file. This approach requires two file handlers per single monitored folder. The +// second grip handles actions which include creating or deleting a directory. If +// these processes are not monitored, only the first grip is created. +type watched struct { + filter uint32 + recursive bool + count uint8 + pathw []uint16 + digrip [2]*grip +} + +// newWatched creates a new watched instance. It splits the filter variable into +// two parts. The first part is responsible for watching all events which can be +// created for a file in watched directory structure and the second one watches +// only directory Create/Remove actions. If all operations succeed, the Create +// message is sent to I/O completion port queue for further processing. +func newWatched(cph syscall.Handle, filter uint32, recursive bool, + path string) (wd *watched, err error) { + wd = &watched{ + filter: filter, + recursive: recursive, + } + if wd.pathw, err = syscall.UTF16FromString(path); err != nil { + return + } + if err = wd.recreate(cph); err != nil { + return + } + return wd, nil +} + +// TODO : doc +func (wd *watched) recreate(cph syscall.Handle) (err error) { + filefilter := wd.filter &^ uint32(FileNotifyChangeDirName) + if err = wd.updateGrip(0, cph, filefilter == 0, filefilter); err != nil { + return + } + dirfilter := wd.filter & uint32(FileNotifyChangeDirName|Create|Remove) + if err = wd.updateGrip(1, cph, dirfilter == 0, wd.filter|uint32(dirmarker)); err != nil { + return + } + wd.filter &^= onlyMachineStates + return +} + +// TODO : doc +func (wd *watched) updateGrip(idx int, cph syscall.Handle, reset bool, + newflag uint32) (err error) { + if reset { + wd.digrip[idx] = nil + } else { + if wd.digrip[idx] == nil { + if wd.digrip[idx], err = newGrip(cph, wd, newflag); err != nil { + wd.closeHandle() + return + } + } else { + wd.digrip[idx].filter = newflag + wd.digrip[idx].recursive = wd.recursive + if err = wd.digrip[idx].register(cph); err != nil { + wd.closeHandle() + return + } + } + wd.count++ + } + return +} + +// closeHandle closes handles that are stored in digrip array. Function always +// tries to close all of the handlers before it exits, even when there are errors +// returned from the operating system kernel. +func (wd *watched) closeHandle() (err error) { + for _, g := range wd.digrip { + if g != nil && g.handle != syscall.InvalidHandle { + switch suberr := syscall.CloseHandle(g.handle); { + case suberr == nil: + g.handle = syscall.InvalidHandle + case err == nil: + err = suberr + } + } + } + return +} + +// watcher implements Watcher interface. It stores a set of watched directories. +// All operations which remove watched objects from map `m` must be performed in +// loop goroutine since these structures are used internally by operating system. +type readdcw struct { + sync.Mutex + m map[string]*watched + cph syscall.Handle + start bool + wg sync.WaitGroup + c chan<- EventInfo +} + +// NewWatcher creates new non-recursive watcher backed by ReadDirectoryChangesW. +func newWatcher(c chan<- EventInfo) watcher { + r := &readdcw{ + m: make(map[string]*watched), + cph: syscall.InvalidHandle, + c: c, + } + runtime.SetFinalizer(r, func(r *readdcw) { + if r.cph != syscall.InvalidHandle { + syscall.CloseHandle(r.cph) + } + }) + return r +} + +// Watch implements notify.Watcher interface. +func (r *readdcw) Watch(path string, event Event) error { + return r.watch(path, event, false) +} + +// RecursiveWatch implements notify.RecursiveWatcher interface. +func (r *readdcw) RecursiveWatch(path string, event Event) error { + return r.watch(path, event, true) +} + +// watch inserts a directory to the group of watched folders. If watched folder +// already exists, function tries to rewatch it with new filters(NOT VALID). Moreover, +// watch starts the main event loop goroutine when called for the first time. +func (r *readdcw) watch(path string, event Event, recursive bool) (err error) { + if event&^(All|fileNotifyChangeAll) != 0 { + return errors.New("notify: unknown event") + } + r.Lock() + wd, ok := r.m[path] + r.Unlock() + if !ok { + if err = r.lazyinit(); err != nil { + return + } + r.Lock() + if wd, ok = r.m[path]; ok { + r.Unlock() + return + } + if wd, err = newWatched(r.cph, uint32(event), recursive, path); err != nil { + r.Unlock() + return + } + r.m[path] = wd + r.Unlock() + } + return nil +} + +// lazyinit creates an I/O completion port and starts the main event processing +// loop. This method uses Double-Checked Locking optimization. +func (r *readdcw) lazyinit() (err error) { + invalid := uintptr(syscall.InvalidHandle) + if atomic.LoadUintptr((*uintptr)(&r.cph)) == invalid { + r.Lock() + defer r.Unlock() + if atomic.LoadUintptr((*uintptr)(&r.cph)) == invalid { + cph := syscall.InvalidHandle + if cph, err = syscall.CreateIoCompletionPort(cph, 0, 0, 0); err != nil { + return + } + r.cph, r.start = cph, true + go r.loop() + } + } + return +} + +// TODO(pknap) : doc +func (r *readdcw) loop() { + var n, key uint32 + var overlapped *syscall.Overlapped + for { + err := syscall.GetQueuedCompletionStatus(r.cph, &n, &key, &overlapped, syscall.INFINITE) + if key == stateCPClose { + r.Lock() + handle := r.cph + r.cph = syscall.InvalidHandle + r.Unlock() + syscall.CloseHandle(handle) + r.wg.Done() + return + } + if overlapped == nil { + // TODO: check key == rewatch delete or 0(panic) + continue + } + overEx := (*overlappedEx)(unsafe.Pointer(overlapped)) + if n == 0 { + r.loopstate(overEx) + } else { + r.loopevent(n, overEx) + if err = overEx.parent.readDirChanges(); err != nil { + // TODO: error handling + } + } + } +} + +// TODO(pknap) : doc +func (r *readdcw) loopstate(overEx *overlappedEx) { + filter := atomic.LoadUint32(&overEx.parent.parent.filter) + if filter&onlyMachineStates == 0 { + return + } + if overEx.parent.parent.count--; overEx.parent.parent.count == 0 { + switch filter & onlyMachineStates { + case stateRewatch: + r.Lock() + overEx.parent.parent.recreate(r.cph) + r.Unlock() + case stateUnwatch: + r.Lock() + delete(r.m, syscall.UTF16ToString(overEx.parent.pathw)) + r.Unlock() + case stateCPClose: + default: + panic(`notify: windows loopstate logic error`) + } + } +} + +// TODO(pknap) : doc +func (r *readdcw) loopevent(n uint32, overEx *overlappedEx) { + events := []*event{} + var currOffset uint32 + for { + raw := (*syscall.FileNotifyInformation)(unsafe.Pointer(&overEx.parent.buffer[currOffset])) + name := syscall.UTF16ToString((*[syscall.MAX_LONG_PATH]uint16)(unsafe.Pointer(&raw.FileName))[:raw.FileNameLength>>1]) + events = append(events, &event{ + pathw: overEx.parent.pathw, + filter: overEx.parent.filter, + action: raw.Action, + name: name, + }) + if raw.NextEntryOffset == 0 { + break + } + if currOffset += raw.NextEntryOffset; currOffset >= n { + break + } + } + r.send(events) +} + +// TODO(pknap) : doc +func (r *readdcw) send(es []*event) { + for _, e := range es { + var syse Event + if e.e, syse = decode(e.filter, e.action); e.e == 0 && syse == 0 { + continue + } + switch { + case e.action == syscall.FILE_ACTION_MODIFIED: + e.ftype = fTypeUnknown + case e.filter&uint32(dirmarker) != 0: + e.ftype = fTypeDirectory + default: + e.ftype = fTypeFile + } + switch { + case e.e == 0: + e.e = syse + case syse != 0: + r.c <- &event{ + pathw: e.pathw, + name: e.name, + ftype: e.ftype, + action: e.action, + filter: e.filter, + e: syse, + } + } + r.c <- e + } +} + +// Rewatch implements notify.Rewatcher interface. +func (r *readdcw) Rewatch(path string, oldevent, newevent Event) error { + return r.rewatch(path, uint32(oldevent), uint32(newevent), false) +} + +// RecursiveRewatch implements notify.RecursiveRewatcher interface. +func (r *readdcw) RecursiveRewatch(oldpath, newpath string, oldevent, + newevent Event) error { + if oldpath != newpath { + if err := r.unwatch(oldpath); err != nil { + return err + } + return r.watch(newpath, newevent, true) + } + return r.rewatch(newpath, uint32(oldevent), uint32(newevent), true) +} + +// TODO : (pknap) doc. +func (r *readdcw) rewatch(path string, oldevent, newevent uint32, recursive bool) (err error) { + if Event(newevent)&^(All|fileNotifyChangeAll) != 0 { + return errors.New("notify: unknown event") + } + var wd *watched + r.Lock() + if wd, err = r.nonStateWatched(path); err != nil { + r.Unlock() + return + } + if wd.filter&(onlyNotifyChanges|onlyNGlobalEvents) != oldevent { + panic(`notify: windows re-watcher logic error`) + } + wd.filter = stateRewatch | newevent + wd.recursive, recursive = recursive, wd.recursive + if err = wd.closeHandle(); err != nil { + wd.filter = oldevent + wd.recursive = recursive + r.Unlock() + return + } + r.Unlock() + return +} + +// TODO : pknap +func (r *readdcw) nonStateWatched(path string) (wd *watched, err error) { + wd, ok := r.m[path] + if !ok || wd == nil { + err = errors.New(`notify: ` + path + ` path is unwatched`) + return + } + if filter := atomic.LoadUint32(&wd.filter); filter&onlyMachineStates != 0 { + err = errors.New(`notify: another re/unwatching operation in progress`) + return + } + return +} + +// Unwatch implements notify.Watcher interface. +func (r *readdcw) Unwatch(path string) error { + return r.unwatch(path) +} + +// RecursiveUnwatch implements notify.RecursiveWatcher interface. +func (r *readdcw) RecursiveUnwatch(path string) error { + return r.unwatch(path) +} + +// TODO : pknap +func (r *readdcw) unwatch(path string) (err error) { + var wd *watched + r.Lock() + if wd, err = r.nonStateWatched(path); err != nil { + r.Unlock() + return + } + wd.filter |= stateUnwatch + if err = wd.closeHandle(); err != nil { + wd.filter &^= stateUnwatch + r.Unlock() + return + } + r.Unlock() + return +} + +// Close resets the whole watcher object, closes all existing file descriptors, +// and sends stateCPClose state as completion key to the main watcher's loop. +func (r *readdcw) Close() (err error) { + r.Lock() + if !r.start { + r.Unlock() + return nil + } + for _, wd := range r.m { + wd.filter &^= onlyMachineStates + wd.filter |= stateCPClose + if e := wd.closeHandle(); e != nil && err == nil { + err = e + } + } + r.start = false + r.Unlock() + r.wg.Add(1) + if e := syscall.PostQueuedCompletionStatus(r.cph, 0, stateCPClose, nil); e != nil && err == nil { + return e + } + r.wg.Wait() + return +} + +// decode creates a notify event from both non-raw filter and action which was +// returned from completion routine. Function may return Event(0) in case when +// filter was replaced by a new value which does not contain fields that are +// valid with passed action. +func decode(filter, action uint32) (Event, Event) { + switch action { + case syscall.FILE_ACTION_ADDED: + return gensys(filter, Create, FileActionAdded) + case syscall.FILE_ACTION_REMOVED: + return gensys(filter, Remove, FileActionRemoved) + case syscall.FILE_ACTION_MODIFIED: + return gensys(filter, Write, FileActionModified) + case syscall.FILE_ACTION_RENAMED_OLD_NAME: + return gensys(filter, Rename, FileActionRenamedOldName) + case syscall.FILE_ACTION_RENAMED_NEW_NAME: + return gensys(filter, Rename, FileActionRenamedNewName) + } + panic(`notify: cannot decode internal mask`) +} + +// gensys decides whether the Windows action, system-independent event or both +// of them should be returned. Since the grip's filter may be atomically changed +// during watcher lifetime, it is possible that neither Windows nor notify masks +// are watched by the user when this function is called. +func gensys(filter uint32, ge, se Event) (gene, syse Event) { + isdir := filter&uint32(dirmarker) != 0 + if isdir && filter&uint32(FileNotifyChangeDirName) != 0 || + !isdir && filter&uint32(FileNotifyChangeFileName) != 0 || + filter&uint32(fileNotifyChangeModified) != 0 { + syse = se + } + if filter&uint32(ge) != 0 { + gene = ge + } + return +} |