Fuchsia: Use mx_handle_wait_many in the eventhandler

runtime/bin/eventhandler_fuchsia.h

Index: runtime/bin/eventhandler_fuchsia.h
diff --git a/runtime/bin/eventhandler_fuchsia.h b/runtime/bin/eventhandler_fuchsia.h
index 013099232471828b81db8bac0a791805bc5f5cef..b168c6208be4d2f1cdebf02feaed9ca58c644931 100644
--- a/runtime/bin/eventhandler_fuchsia.h
+++ b/runtime/bin/eventhandler_fuchsia.h
@@ -9,11 +9,82 @@
 #error Do not include eventhandler_fuchsia.h directly; use eventhandler.h instead.
 #endif
 
+#include <errno.h>
 #include <magenta/syscalls.h>
 
+#include "platform/signal_blocker.h"
+
 namespace dart {
 namespace bin {
 
+class DescriptorInfo : public DescriptorInfoBase {
+ public:
+  explicit DescriptorInfo(intptr_t fd) : DescriptorInfoBase(fd) { }
+
+  virtual ~DescriptorInfo() { }
+
+  virtual void Close() {
+    VOID_TEMP_FAILURE_RETRY(close(fd_));
+    fd_ = -1;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DescriptorInfo);
+};
+
+class DescriptorInfoSingle
+    : public DescriptorInfoSingleMixin<DescriptorInfo> {
+ public:
+  explicit DescriptorInfoSingle(intptr_t fd)
+      : DescriptorInfoSingleMixin(fd, false) {}
+  virtual ~DescriptorInfoSingle() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DescriptorInfoSingle);
+};
+
+class DescriptorInfoMultiple
+    : public DescriptorInfoMultipleMixin<DescriptorInfo> {
+ public:
+  explicit DescriptorInfoMultiple(intptr_t fd)
+      : DescriptorInfoMultipleMixin(fd, false) {}
+  virtual ~DescriptorInfoMultiple() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DescriptorInfoMultiple);
+};
+
+// Information needed to call mx_handle_wait_many(), and to handle events.
+class MagentaWaitManyInfo {
+ public:
+  MagentaWaitManyInfo();
+  ~MagentaWaitManyInfo();
+
+  intptr_t capacity() const { return capacity_; }
+  intptr_t size() const { return size_; }
+  DescriptorInfo** descriptor_infos() const { return descriptor_infos_; }
+  mx_handle_t* handles() const { return handles_; }
+  mx_signals_t* signals() const { return signals_; }
+  mx_signals_state_t* signals_states() const { return signals_states_; }
+
+  void AddHandle(mx_handle_t handle, mx_signals_t signals, DescriptorInfo* di);
+  void RemoveHandle(mx_handle_t handle);
+
+ private:
+  static const intptr_t kInitialCapacity = 32;
+
+  void GrowArraysIfNeeded(intptr_t desired_size);
+
+  intptr_t capacity_;
+  intptr_t size_;
+  DescriptorInfo** descriptor_infos_;
+  mx_handle_t* handles_;
+  mx_signals_t* signals_;
+  mx_signals_state_t* signals_states_;
+
+  DISALLOW_COPY_AND_ASSIGN(MagentaWaitManyInfo);
+};
+
 class EventHandlerImplementation {
  public:
   EventHandlerImplementation();
@@ -23,6 +94,8 @@ class EventHandlerImplementation {
   void Start(EventHandler* handler);
   void Shutdown();
 
+  const MagentaWaitManyInfo& info() const { return info_; }
+
  private:
   int64_t GetTimeout() const;
   void HandleEvents();
@@ -35,6 +108,8 @@ class EventHandlerImplementation {
   bool shutdown_;
   mx_handle_t interrupt_handles_[2];
 
+  MagentaWaitManyInfo info_;
+
   DISALLOW_COPY_AND_ASSIGN(EventHandlerImplementation);
 };