wallet-core/node_modules/chokidar/lib/fsevents-handler.js

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2017-05-03 15:35:00 +02:00
'use strict';
var fs = require('fs');
var sysPath = require('path');
var readdirp = require('readdirp');
var fsevents;
try { fsevents = require('fsevents'); } catch (error) {}
// fsevents instance helper functions
// object to hold per-process fsevents instances
// (may be shared across chokidar FSWatcher instances)
var FSEventsWatchers = Object.create(null);
// Threshold of duplicate path prefixes at which to start
// consolidating going forward
var consolidateThreshhold = 10;
// Private function: Instantiates the fsevents interface
// * path - string, path to be watched
// * callback - function, called when fsevents is bound and ready
// Returns new fsevents instance
function createFSEventsInstance(path, callback) {
return (new fsevents(path)).on('fsevent', callback).start();
}
// Private function: Instantiates the fsevents interface or binds listeners
// to an existing one covering the same file tree
// * path - string, path to be watched
// * realPath - string, real path (in case of symlinks)
// * listener - function, called when fsevents emits events
// * rawEmitter - function, passes data to listeners of the 'raw' event
// Returns close function
function setFSEventsListener(path, realPath, listener, rawEmitter) {
var watchPath = sysPath.extname(path) ? sysPath.dirname(path) : path;
var watchContainer;
var parentPath = sysPath.dirname(watchPath);
// If we've accumulated a substantial number of paths that
// could have been consolidated by watching one directory
// above the current one, create a watcher on the parent
// path instead, so that we do consolidate going forward.
if (couldConsolidate(parentPath)) {
watchPath = parentPath;
}
var resolvedPath = sysPath.resolve(path);
var hasSymlink = resolvedPath !== realPath;
function filteredListener(fullPath, flags, info) {
if (hasSymlink) fullPath = fullPath.replace(realPath, resolvedPath);
if (
fullPath === resolvedPath ||
!fullPath.indexOf(resolvedPath + sysPath.sep)
) listener(fullPath, flags, info);
}
// check if there is already a watcher on a parent path
// modifies `watchPath` to the parent path when it finds a match
function watchedParent() {
return Object.keys(FSEventsWatchers).some(function(watchedPath) {
// condition is met when indexOf returns 0
if (!realPath.indexOf(sysPath.resolve(watchedPath) + sysPath.sep)) {
watchPath = watchedPath;
return true;
}
});
}
if (watchPath in FSEventsWatchers || watchedParent()) {
watchContainer = FSEventsWatchers[watchPath];
watchContainer.listeners.push(filteredListener);
} else {
watchContainer = FSEventsWatchers[watchPath] = {
listeners: [filteredListener],
rawEmitters: [rawEmitter],
watcher: createFSEventsInstance(watchPath, function(fullPath, flags) {
var info = fsevents.getInfo(fullPath, flags);
watchContainer.listeners.forEach(function(listener) {
listener(fullPath, flags, info);
});
watchContainer.rawEmitters.forEach(function(emitter) {
emitter(info.event, fullPath, info);
});
})
};
}
var listenerIndex = watchContainer.listeners.length - 1;
// removes this instance's listeners and closes the underlying fsevents
// instance if there are no more listeners left
return function close() {
delete watchContainer.listeners[listenerIndex];
delete watchContainer.rawEmitters[listenerIndex];
if (!Object.keys(watchContainer.listeners).length) {
watchContainer.watcher.stop();
delete FSEventsWatchers[watchPath];
}
};
}
// Decide whether or not we should start a new higher-level
// parent watcher
function couldConsolidate(path) {
var keys = Object.keys(FSEventsWatchers);
var count = 0;
for (var i = 0, len = keys.length; i < len; ++i) {
var watchPath = keys[i];
if (watchPath.indexOf(path) === 0) {
count++;
if (count >= consolidateThreshhold) {
return true;
}
}
}
return false;
}
// returns boolean indicating whether fsevents can be used
function canUse() {
return fsevents && Object.keys(FSEventsWatchers).length < 128;
}
// determines subdirectory traversal levels from root to path
function depth(path, root) {
var i = 0;
while (!path.indexOf(root) && (path = sysPath.dirname(path)) !== root) i++;
return i;
}
// fake constructor for attaching fsevents-specific prototype methods that
// will be copied to FSWatcher's prototype
function FsEventsHandler() {}
// Private method: Handle symlinks encountered during directory scan
// * watchPath - string, file/dir path to be watched with fsevents
// * realPath - string, real path (in case of symlinks)
// * transform - function, path transformer
// * globFilter - function, path filter in case a glob pattern was provided
// Returns close function for the watcher instance
FsEventsHandler.prototype._watchWithFsEvents =
function(watchPath, realPath, transform, globFilter) {
if (this._isIgnored(watchPath)) return;
var watchCallback = function(fullPath, flags, info) {
if (
this.options.depth !== undefined &&
depth(fullPath, realPath) > this.options.depth
) return;
var path = transform(sysPath.join(
watchPath, sysPath.relative(watchPath, fullPath)
));
if (globFilter && !globFilter(path)) return;
// ensure directories are tracked
var parent = sysPath.dirname(path);
var item = sysPath.basename(path);
var watchedDir = this._getWatchedDir(
info.type === 'directory' ? path : parent
);
var checkIgnored = function(stats) {
if (this._isIgnored(path, stats)) {
this._ignoredPaths[path] = true;
if (stats && stats.isDirectory()) {
this._ignoredPaths[path + '/**/*'] = true;
}
return true;
} else {
delete this._ignoredPaths[path];
delete this._ignoredPaths[path + '/**/*'];
}
}.bind(this);
var handleEvent = function(event) {
if (checkIgnored()) return;
if (event === 'unlink') {
// suppress unlink events on never before seen files
if (info.type === 'directory' || watchedDir.has(item)) {
this._remove(parent, item);
}
} else {
if (event === 'add') {
// track new directories
if (info.type === 'directory') this._getWatchedDir(path);
if (info.type === 'symlink' && this.options.followSymlinks) {
// push symlinks back to the top of the stack to get handled
var curDepth = this.options.depth === undefined ?
undefined : depth(fullPath, realPath) + 1;
return this._addToFsEvents(path, false, true, curDepth);
} else {
// track new paths
// (other than symlinks being followed, which will be tracked soon)
this._getWatchedDir(parent).add(item);
}
}
var eventName = info.type === 'directory' ? event + 'Dir' : event;
this._emit(eventName, path);
if (eventName === 'addDir') this._addToFsEvents(path, false, true);
}
}.bind(this);
function addOrChange() {
handleEvent(watchedDir.has(item) ? 'change' : 'add');
}
function checkFd() {
fs.open(path, 'r', function(error, fd) {
if (fd) fs.close(fd);
error && error.code !== 'EACCES' ?
handleEvent('unlink') : addOrChange();
});
}
// correct for wrong events emitted
var wrongEventFlags = [
69888, 70400, 71424, 72704, 73472, 131328, 131840, 262912
];
if (wrongEventFlags.indexOf(flags) !== -1 || info.event === 'unknown') {
if (typeof this.options.ignored === 'function') {
fs.stat(path, function(error, stats) {
if (checkIgnored(stats)) return;
stats ? addOrChange() : handleEvent('unlink');
});
} else {
checkFd();
}
} else {
switch (info.event) {
case 'created':
case 'modified':
return addOrChange();
case 'deleted':
case 'moved':
return checkFd();
}
}
}.bind(this);
var closer = setFSEventsListener(
watchPath,
realPath,
watchCallback,
this.emit.bind(this, 'raw')
);
this._emitReady();
return closer;
};
// Private method: Handle symlinks encountered during directory scan
// * linkPath - string, path to symlink
// * fullPath - string, absolute path to the symlink
// * transform - function, pre-existing path transformer
// * curDepth - int, level of subdirectories traversed to where symlink is
// Returns nothing
FsEventsHandler.prototype._handleFsEventsSymlink =
function(linkPath, fullPath, transform, curDepth) {
// don't follow the same symlink more than once
if (this._symlinkPaths[fullPath]) return;
else this._symlinkPaths[fullPath] = true;
this._readyCount++;
fs.realpath(linkPath, function(error, linkTarget) {
if (this._handleError(error) || this._isIgnored(linkTarget)) {
return this._emitReady();
}
this._readyCount++;
// add the linkTarget for watching with a wrapper for transform
// that causes emitted paths to incorporate the link's path
this._addToFsEvents(linkTarget || linkPath, function(path) {
var dotSlash = '.' + sysPath.sep;
var aliasedPath = linkPath;
if (linkTarget && linkTarget !== dotSlash) {
aliasedPath = path.replace(linkTarget, linkPath);
} else if (path !== dotSlash) {
aliasedPath = sysPath.join(linkPath, path);
}
return transform(aliasedPath);
}, false, curDepth);
}.bind(this));
};
// Private method: Handle added path with fsevents
// * path - string, file/directory path or glob pattern
// * transform - function, converts working path to what the user expects
// * forceAdd - boolean, ensure add is emitted
// * priorDepth - int, level of subdirectories already traversed
// Returns nothing
FsEventsHandler.prototype._addToFsEvents =
function(path, transform, forceAdd, priorDepth) {
// applies transform if provided, otherwise returns same value
var processPath = typeof transform === 'function' ?
transform : function(val) { return val; };
var emitAdd = function(newPath, stats) {
var pp = processPath(newPath);
var isDir = stats.isDirectory();
var dirObj = this._getWatchedDir(sysPath.dirname(pp));
var base = sysPath.basename(pp);
// ensure empty dirs get tracked
if (isDir) this._getWatchedDir(pp);
if (dirObj.has(base)) return;
dirObj.add(base);
if (!this.options.ignoreInitial || forceAdd === true) {
this._emit(isDir ? 'addDir' : 'add', pp, stats);
}
}.bind(this);
var wh = this._getWatchHelpers(path);
// evaluate what is at the path we're being asked to watch
fs[wh.statMethod](wh.watchPath, function(error, stats) {
if (this._handleError(error) || this._isIgnored(wh.watchPath, stats)) {
this._emitReady();
return this._emitReady();
}
if (stats.isDirectory()) {
// emit addDir unless this is a glob parent
if (!wh.globFilter) emitAdd(processPath(path), stats);
// don't recurse further if it would exceed depth setting
if (priorDepth && priorDepth > this.options.depth) return;
// scan the contents of the dir
readdirp({
root: wh.watchPath,
entryType: 'all',
fileFilter: wh.filterPath,
directoryFilter: wh.filterDir,
lstat: true,
depth: this.options.depth - (priorDepth || 0)
}).on('data', function(entry) {
// need to check filterPath on dirs b/c filterDir is less restrictive
if (entry.stat.isDirectory() && !wh.filterPath(entry)) return;
var joinedPath = sysPath.join(wh.watchPath, entry.path);
var fullPath = entry.fullPath;
if (wh.followSymlinks && entry.stat.isSymbolicLink()) {
// preserve the current depth here since it can't be derived from
// real paths past the symlink
var curDepth = this.options.depth === undefined ?
undefined : depth(joinedPath, sysPath.resolve(wh.watchPath)) + 1;
this._handleFsEventsSymlink(joinedPath, fullPath, processPath, curDepth);
} else {
emitAdd(joinedPath, entry.stat);
}
}.bind(this)).on('error', function() {
// Ignore readdirp errors
}).on('end', this._emitReady);
} else {
emitAdd(wh.watchPath, stats);
this._emitReady();
}
}.bind(this));
if (this.options.persistent && forceAdd !== true) {
var initWatch = function(error, realPath) {
var closer = this._watchWithFsEvents(
wh.watchPath,
sysPath.resolve(realPath || wh.watchPath),
processPath,
wh.globFilter
);
if (closer) this._closers[path] = closer;
}.bind(this);
if (typeof transform === 'function') {
// realpath has already been resolved
initWatch();
} else {
fs.realpath(wh.watchPath, initWatch);
}
}
};
module.exports = FsEventsHandler;
module.exports.canUse = canUse;