Add Watcher implementations (#2)

azure-pipelines-template.yml

@@ -0,0 +1,30 @@
+jobs:
+- job: ${{ parameters.name }}
+  pool: 
+    vmImage: ${{ parameters.vmImage }}
+  ${{ if eq(parameters.name, 'Linux') }}:
+    container: jotadrilo/watchman:latest
+  strategy:
+    matrix:
+      node_8_x:
+        node_version: 8.x
+      node_10_x:
+        node_version: 10.x
+    maxParallel: 3
+  steps:
+  - task: NodeTool@0
+    inputs:
+      versionSpec: $(node_version)
+    displayName: 'Install Node.js'
+
+  # Install Watchman
+  - ${{ if eq(parameters.name, 'macOS') }}:
+    - script: |
+        brew update
+        brew install watchman
+      displayName: Install Watchman
+
+  - script: npm install
+    displayName: 'Install dependencies'
+  - script: npm test
+    displayName: 'Run tests'

azure-pipelines.yml

@@ -0,0 +1,15 @@
+jobs:
+- template: azure-pipelines-template.yml
+  parameters:
+    name: macOS
+    vmImage: macOS-10.13
+
+- template: azure-pipelines-template.yml
+  parameters:
+    name: Linux
+    vmImage: ubuntu-16.04
+
+- template: azure-pipelines-template.yml
+  parameters:
+   name: Windows
+   vmImage: vs2017-win2016

binding.gyp

@@ -3,17 +3,17 @@
     {
       "target_name": "fschanges",
       "defines": [ "NAPI_DISABLE_CPP_EXCEPTIONS" ],
-      "sources": [ "src/FSChanges.cc" ],
+      "sources": [ "src/FSChanges.cc", "src/Watcher.cc", "src/Backend.cc" ],
       "include_dirs" : ["<!@(node -p \"require('node-addon-api').include\")"],
       "dependencies": ["<!(node -p \"require('node-addon-api').gyp\")"],
-      "cflags!": ["-fexceptions"],
-      "cflags_cc!": ["-fexceptions"],
+      'cflags!': [ '-fno-exceptions' ],
+      'cflags_cc!': [ '-fno-exceptions' ],
       "conditions": [
         ['OS=="mac"', {
           "sources": [
             "src/watchman/BSER.cc",
             "src/watchman/watchman.cc",
-            "src/shared/brute.cc",
+            "src/shared/BruteForceBackend.cc",
             "src/unix/fts.cc",
             "src/macos/FSEvents.cc"
           ],
@@ -33,22 +33,30 @@
           "sources": [
             "src/watchman/BSER.cc",
             "src/watchman/watchman.cc",
-            "src/shared/brute.cc",
+            "src/shared/BruteForceBackend.cc",
+            "src/linux/InotifyBackend.cc",
             "src/unix/fts.cc"
           ],
           "defines": [
             "WATCHMAN",
+            "INOTIFY",
             "BRUTE_FORCE"
           ]
         }],
         ['OS=="win"', {
           "sources": [
-            "src/shared/brute.cc",
-            "src/windows/win.cc"
+            "src/shared/BruteForceBackend.cc",
+            "src/windows/WindowsBackend.cc"
           ],
           "defines": [
+            "WINDOWS",
             "BRUTE_FORCE"
-          ]
+          ],
+          "msvs_settings": {
+            "VCCLCompilerTool": {
+              "ExceptionHandling": 1,  # /EHsc
+            }
+          }
         }]
       ]
     }

index.js

@@ -20,4 +20,19 @@ async function run() {
   console.timeEnd('write');
 }
 
-run();
+// run();
+
+let fn = events => {
+  console.log(events);
+  // fschanges.unsubscribe(dir, fn, {ignore: [dir + '/.git']});
+};
+
+fschanges.subscribe(dir, fn, {ignore: [dir + '/.git']});
+
+// let w = new Watcher(dir);
+// w.getEventsSince(snapshotPath);
+// w.writeSnapshot(snapshotPath);
+// w.subscribe(events => {
+
+// });
+// w.unsubscribe();

package.json

@@ -1,6 +1,13 @@
 {
   "main": "build/Release/fschanges.node",
+  "scripts": {
+    "test": "mocha"
+  },
   "dependencies": {
     "node-addon-api": "^1.6.2"
+  },
+  "devDependencies": {
+    "fs-extra": "^7.0.1",
+    "mocha": "^6.0.2"
   }
 }

src/Backend.cc

@@ -0,0 +1,129 @@
+#ifdef FS_EVENTS
+#include "macos/FSEvents.hh"
+#endif
+#ifdef WATCHMAN
+#include "watchman/watchman.hh"
+#endif
+#ifdef WINDOWS
+#include "windows/WindowsBackend.hh"
+#endif
+#ifdef INOTIFY
+#include "linux/InotifyBackend.hh"
+#endif
+#include "shared/BruteForceBackend.hh"
+
+#include "Backend.hh"
+#include <unordered_map>
+
+static std::unordered_map<std::string, std::shared_ptr<Backend>> sharedBackends;
+
+std::shared_ptr<Backend> getBackend(std::string backend) {
+  // Use FSEvents on macOS by default.
+  // Use watchman by default if available on other platforms.
+  // Fall back to brute force.
+  #ifdef FS_EVENTS
+    if (backend == "fs-events" || backend == "default") {
+      return std::make_shared<FSEventsBackend>();
+    }
+  #endif
+  #ifdef WATCHMAN
+    if ((backend == "watchman" || backend == "default") && WatchmanBackend::checkAvailable()) {
+      return std::make_shared<WatchmanBackend>();
+    }
+  #endif
+  #ifdef WINDOWS
+    if (backend == "windows" || backend == "default") {
+      return std::make_shared<WindowsBackend>();
+    }
+  #endif
+  #ifdef INOTIFY
+    if (backend == "inotify" || backend == "default") {
+      return std::make_shared<InotifyBackend>();
+    }
+  #endif
+  if (backend == "brute-force" || backend == "default") {
+    return std::make_shared<BruteForceBackend>();
+  }
+
+  return nullptr;
+}
+
+std::shared_ptr<Backend> Backend::getShared(std::string backend) {
+  auto found = sharedBackends.find(backend);
+  if (found != sharedBackends.end()) {
+    return found->second;
+  }
+
+  auto result = getBackend(backend);
+  if (!result) {
+    return getShared("default");
+  }
+
+  result->run();
+  sharedBackends.emplace(backend, result);
+  return result;
+}
+
+void removeShared(Backend *backend) {
+  for (auto it = sharedBackends.begin(); it != sharedBackends.end(); it++) {
+    if (it->second.get() == backend) {
+      sharedBackends.erase(it);
+      break;
+    }
+  }
+}
+
+void Backend::run() {
+  mThread = std::thread([this] () {
+    start();
+  });
+
+  if (mThread.joinable()) {
+    mStartedSignal.wait();
+  }
+}
+
+void Backend::notifyStarted() {
+  mStartedSignal.notify();
+}
+
+void Backend::start() {
+  notifyStarted();
+}
+
+Backend::~Backend() {
+  std::unique_lock<std::mutex> lock(mMutex);
+
+  // Unwatch all subscriptions so that their state gets cleaned up
+  for (auto it = mSubscriptions.begin(); it != mSubscriptions.end(); it++) {
+    unwatch(**it);
+  }
+
+  // Wait for thread to stop
+  if (mThread.joinable()) {
+    mThread.join();
+  }
+}
+
+void Backend::watch(Watcher &watcher) {
+  std::unique_lock<std::mutex> lock(mMutex);
+  auto res = mSubscriptions.insert(&watcher);
+  if (res.second) {
+    this->subscribe(watcher);
+  }
+}
+
+void Backend::unwatch(Watcher &watcher) {
+  std::unique_lock<std::mutex> lock(mMutex);
+  size_t deleted = mSubscriptions.erase(&watcher);
+  if (deleted > 0) {
+    this->unsubscribe(watcher);
+    unref();
+  }
+}
+
+void Backend::unref() {
+  if (mSubscriptions.size() == 0) {
+    removeShared(this);
+  }
+}

src/Backend.hh

@@ -1,43 +1,34 @@
 #ifndef BACKEND_H
 #define BACKEND_H
 
-#include "./Event.hh"
+#include "Event.hh"
+#include "Watcher.hh"
+#include "Signal.hh"
+#include <thread>
 
-#ifdef FS_EVENTS
-struct FSEventsBackend {
-  static void writeSnapshot(std::string *dir, std::string *snapshotPath, std::unordered_set<std::string> *ignore);
-  static EventList *getEventsSince(std::string *dir, std::string *snapshotPath, std::unordered_set<std::string> *ignore);
-};
-#endif
+class Backend {
+public:
+  virtual ~Backend();
+  void run();
+  void notifyStarted();
 
-#ifdef WATCHMAN
-struct WatchmanBackend {
-  static bool check();
-  static void writeSnapshot(std::string *dir, std::string *snapshotPath, std::unordered_set<std::string> *ignore);
-  static EventList *getEventsSince(std::string *dir, std::string *snapshotPath, std::unordered_set<std::string> *ignore);
-};
-#endif
+  virtual void start();
+  virtual void writeSnapshot(Watcher &watcher, std::string *snapshotPath) = 0;
+  virtual void getEventsSince(Watcher &watcher, std::string *snapshotPath) = 0;
+  virtual void subscribe(Watcher &watcher) = 0;
+  virtual void unsubscribe(Watcher &watcher) = 0;
 
-struct BruteForceBackend {
-  static void writeSnapshot(std::string *dir, std::string *snapshotPath, std::unordered_set<std::string> *ignore);
-  static EventList *getEventsSince(std::string *dir, std::string *snapshotPath, std::unordered_set<std::string> *ignore);
-};
+  static std::shared_ptr<Backend> getShared(std::string backend);
 
-// Use FSEvents on macOS by default.
-// Use watchman by default if available on other platforms.
-// Fall back to brute force.
-#ifdef FS_EVENTS
-#define DEFAULT_BACKEND(method) FSEventsBackend::method
-#elif WATCHMAN
-#define DEFAULT_BACKEND(method) (WatchmanBackend::check() ? WatchmanBackend::method : BruteForceBackend::method)
-#else
-#define DEFAULT_BACKEND(method) BruteForceBackend::method
-#endif
+  void watch(Watcher &watcher);
+  void unwatch(Watcher &watcher);
+  void unref();
 
-#define GET_BACKEND(backend, method) \
-  (backend == "watchman" && WATCHMAN && WatchmanBackend::check() ? WatchmanBackend::method \
-    : backend == "fs-events" && FS_EVENTS ? FSEventsBackend::method \
-    : backend == "brute-force" ? BruteForceBackend::method \
-    : DEFAULT_BACKEND(method))
+  std::mutex mMutex;
+  std::thread mThread;
+private:
+  std::unordered_set<Watcher *> mSubscriptions;
+  Signal mStartedSignal;
+};
 
 #endif