Signal handling.

runtime/bin/process.h

Index: runtime/bin/process.h
diff --git a/runtime/bin/process.h b/runtime/bin/process.h
index 02a9ecc845372bf46fa04c0ce5cb2f2c32e5d4a1..4709770304e1c1b012b50c4a328760f966b6368f 100644
--- a/runtime/bin/process.h
+++ b/runtime/bin/process.h
@@ -84,6 +84,9 @@ class Process {
 
   static intptr_t CurrentProcessId();
 
+  static intptr_t SetSignalHandler(intptr_t signal);
+  static void ClearSignalHandler(intptr_t signal);
+
   static Dart_Handle GetProcessIdNativeField(Dart_Handle process,
                                              intptr_t* pid);
   static Dart_Handle SetProcessIdNativeField(Dart_Handle process,
@@ -98,6 +101,46 @@ class Process {
 };
 
 
+class SignalInfo {
+ public:
+  SignalInfo(int fd, int signal, SignalInfo* prev = NULL)
+      : fd_(fd),
+        signal_(signal),
+        // SignalInfo is expected to be created when in a isolate.
+        port_(Dart_GetMainPortId()),
+        next_(NULL),
+        prev_(prev) {
+    if (prev_ != NULL) {
+      prev_->next_ = this;
+    }
+  }
+
+  ~SignalInfo();
+
+  void Unlink() {
+    if (prev_ != NULL) {
+      prev_->next_ = next_;
+    }
+    if (next_ != NULL) {
+      next_->prev_ = prev_;
+    }
+  }
+
+  int fd() const { return fd_; }
+  int signal() const { return signal_; }
+  Dart_Port port() const { return port_; }
+  SignalInfo* next() const { return next_; }
+
+ private:
+  int fd_;
+  int signal_;
+  // The port_ is used to identify what isolate the signal-info belongs to.
+  Dart_Port port_;
+  SignalInfo* next_;
+  SignalInfo* prev_;
+};
+
+
 // Utility class for collecting the output when running a process
 // synchronously by using Process::Wait. This class is sub-classed in
 // the platform specific files to implement reading into the buffers