Introduce optional 'bool shared' parameter to ServerSocket.bind() ...

dart/runtime/bin/eventhandler.h

Index: dart/runtime/bin/eventhandler.h
diff --git a/dart/runtime/bin/eventhandler.h b/dart/runtime/bin/eventhandler.h
index 80efaca65775a1c88f9dc4eba0ee7cf391872cda..3b35a4c95694d35b01b08db9b08b144965cee01e 100644
--- a/dart/runtime/bin/eventhandler.h
+++ b/dart/runtime/bin/eventhandler.h
@@ -6,8 +6,11 @@
 #define BIN_EVENTHANDLER_H_
 
 #include "bin/builtin.h"
+#include "bin/dartutils.h"
 #include "bin/isolate_data.h"
 
+#include "platform/hashmap.h"
+
 namespace dart {
 namespace bin {
 
@@ -29,6 +32,11 @@ enum MessageFlags {
   kPipe = 17,
 };
 
+#define EVENT_MASK ((1 << kInEvent) | \
+                    (1 << kOutEvent) | \
+                    (1 << kErrorEvent) | \
+                    (1 << kCloseEvent) | \
+                    (1 << kDestroyedEvent))
 #define COMMAND_MASK ((1 << kCloseCommand) | \
                       (1 << kShutdownReadCommand) | \
                       (1 << kShutdownWriteCommand) | \
@@ -94,6 +102,436 @@ class TimeoutQueue {
   Timeout* timeouts_;
 };
 
+
+template<typename T>
+class CircularLinkedList {
+ public:
+  CircularLinkedList() : head_(NULL) {}
+
+  // Returns true if the list was empty.
+  bool Add(T t) {
+    Entry* e = new Entry(t);
+    if (head_ == NULL) {
+      // Empty list, make e head, and point to itself.
+      e->next_ = e;
+      e->prev_ = e;
+      head_ = e;
+      return true;
+    } else {
+      // Insert e as the last element in the list.
+      e->prev_ = head_->prev_;
+      e->next_ = head_;
+      e->prev_->next_ = e;
+      head_->prev_ = e;
+      return false;
+    }
+  }
+
+  void RemoveHead() {
+    Entry* e = head_;
+    if (e->next_ == e) {
+      head_ = NULL;
+    } else {
+      e->prev_->next_ = e->next_;
+      e->next_->prev_ = e->prev_;
+      head_ = e->next_;
+    }
+    delete e;
+  }
+
+  void Remove(T item) {
+    if (head_ == NULL) {
+      return;
+    } else if (head_ == head_->next_) {
+      if (head_->t == item) {
+        head_ = NULL;
+        return;
+      }
+    } else {
+      Entry *current = head_;
+      do {
+        if (current->t == item) {
+          Entry *next = current->next_;
+          Entry *prev = current->prev_;
+          prev->next_ = next;
+          next->prev_ = prev;
+          delete current;
+          return;
+        }
+      } while (current != head_);
+    }
+  }
+
+  T head() const { return head_->t; }
+
+  bool HasHead() const {
+    return head_ != NULL;
+  }
+
+  void Rotate() {
+    head_ = head_->next_;
+  }
+
+ private:
+  struct Entry {
+    explicit Entry(const T& t) : t(t) {}
+    const T t;
+    Entry* next_;
+    Entry* prev_;
+  };
+
+  Entry* head_;
+};
+
+
+class DescriptorInfoBase {
+ public:
+  explicit DescriptorInfoBase(intptr_t fd) : fd_(fd) {
+    ASSERT(fd_ != -1);
+  }
+
+  virtual ~DescriptorInfoBase() {}
+
+  intptr_t fd() { return fd_; }
+
+
+  // Type of socket.
+
+  virtual bool IsListeningSocket() const = 0;
+
+
+  // Ports.
+
+  virtual bool SetPortAndMask(Dart_Port port, intptr_t mask) = 0;
+
+  virtual bool RemovePort(Dart_Port port) = 0;
+
+  // Returns the next port which should be used for sending events to.
+  virtual Dart_Port NextPort() = 0;
+
+  virtual bool HasNextPort() = 0;
+
+  // Will post `data` to all known Dart_Ports.
+  virtual void SendToAll(uintptr_t data) = 0;
+
+
+  // Tokens.
+
+  // Returns true if the last token was taken.
+  virtual bool TakeToken() = 0;
+
+  // Returns true if the tokens was 0 before adding.
+  virtual bool ReturnTokens(Dart_Port port, int count) = 0;
+
+  // Returns true if for any registired Dart_port tokens are available.
+  virtual bool HasTokens() const = 0;
+
+
+  // Other.
+
+  virtual intptr_t Mask() = 0;
+
+  virtual void Close() = 0;
+
+ protected:
+  intptr_t fd_;
+};
+
+
+// Describes a OS descriptor (e.g. file descriptor on linux or HANDLE on
+// windows) which is connected to a single Dart_Port.
+//
+// Subclasses of this class can be e.g. connected tcp sockets
+template<typename SI>
+class DescriptorInfoSingleMixin : public SI {
+ public:
+  explicit DescriptorInfoSingleMixin(intptr_t fd)
+      : SI(fd), port_(0), tokens_(16), mask_(0) {}
+
+  virtual ~DescriptorInfoSingleMixin() { }
+
+  virtual bool IsListeningSocket() const { return false; }
+
+  virtual bool SetPortAndMask(Dart_Port port, intptr_t mask) {
+    ASSERT(port_ == 0 || port == port_);
+    port_ = port;
+    mask_ = mask;
+    return true;
+  }
+
+  virtual bool RemovePort(Dart_Port port) {
+    // TODO(kustermann): Find out where we call RemovePort() with the invalid
+    // port. Afterwards remove the part in the ASSERT here.
+    ASSERT(port_ == 0 || port_ == port);
+    port_ = 0;
+    return true;
+  }
+
+  virtual Dart_Port NextPort() {
+    ASSERT(port_ != 0);
+    return port_;
+  }
+
+  virtual bool HasNextPort() {
+    return port_ != 0;
+  }
+
+  virtual void SendToAll(uintptr_t data) {
+    if (port_ != 0) {
+      DartUtils::PostInt32(port_, data);
+    }
+  }
+
+  virtual bool TakeToken() {
+    ASSERT(tokens_ > 0);
+    tokens_--;
+    return tokens_ == 0;
+  }
+
+  virtual bool ReturnTokens(Dart_Port port, int count) {
+    ASSERT(port_ == port);
+    ASSERT(tokens_ >= 0);
+    bool was_empty = tokens_ == 0;
+    tokens_ += count;
+    return was_empty;
+  }
+
+  virtual bool HasTokens() const { return tokens_ > 0; }
+
+  virtual intptr_t Mask() {
+    return mask_;
+  }
+
+  virtual void Close() {
+    SI::Close();
+  }
+
+ private:
+  Dart_Port port_;
+  int tokens_;
+  intptr_t mask_;
+};
+
+
+// Describes a OS descriptor (e.g. file descriptor on linux or HANDLE on
+// windows) which is connected to multiple Dart_Port's.
+//
+// Subclasses of this class can be e.g. a listening socket which multiple
+// isolates are listening on.
+template<typename SI>
+class DescriptorInfoMultipleMixin : public SI {
+ private:
+  static const int kTokenCount = 4;
+
+  static bool SamePortValue(void* key1, void* key2) {
+    return reinterpret_cast<Dart_Port>(key1) ==
+        reinterpret_cast<Dart_Port>(key2);
+  }
+
+  static uint32_t GetHashmapHashFromPort(Dart_Port port) {
+    return static_cast<uint32_t>(port & 0xFFFFFFFF);
+  }
+
+  static void* GetHashmapKeyFromPort(Dart_Port port) {
+    return reinterpret_cast<void*>(port);
+  }
+
+  static bool IsReadingMask(intptr_t mask) {
+    if (mask == (1 << kInEvent)) {
+      return true;
+    } else {
+      ASSERT(mask == 0);
+      return false;
+    }
+  }
+
+  struct PortEntry {
+    Dart_Port dart_port;
+    intptr_t is_reading;
+    intptr_t token_count;
+
+    bool IsReady() { return token_count > 0 && is_reading; }
+  };
+
+ public:
+  explicit DescriptorInfoMultipleMixin(intptr_t fd)
+      : SI(fd), tokens_map_(&SamePortValue, 4) {}
+
+  virtual ~DescriptorInfoMultipleMixin() {}
+
+  virtual bool IsListeningSocket() const { return true; }
+
+  virtual bool SetPortAndMask(Dart_Port port, intptr_t mask) {
+    bool was_empty = !active_readers_.HasHead();
+    HashMap::Entry* entry = tokens_map_.Lookup(
+        GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port), true);
+    PortEntry* pentry;
+    if (entry->value == NULL) {
+      pentry = new PortEntry();
+      pentry->dart_port = port;
+      pentry->token_count = kTokenCount;
+      pentry->is_reading = IsReadingMask(mask);
+      entry->value = reinterpret_cast<void*>(pentry);
+
+      if (pentry->IsReady()) {
+        active_readers_.Add(pentry);
+      }
+    } else {
+      pentry = reinterpret_cast<PortEntry*>(entry->value);
+      bool was_ready = pentry->IsReady();
+      pentry->is_reading = IsReadingMask(mask);
+      bool is_ready = pentry->IsReady();
+
+      if (was_ready && !is_ready) {
+        active_readers_.Remove(pentry);
+      } else if (!was_ready && is_ready) {
+        active_readers_.Add(pentry);
+      }
+    }
+
+#ifdef DEBUG
+    // To ensure that all readers are ready.
+    PortEntry* root = reinterpret_cast<PortEntry*>(active_readers_.head());
+
+    int ready_count = 0;
+    if (root != NULL) {
+      PortEntry* current = root;
+      do {
+        ASSERT(current->IsReady());
+        ready_count++;
+        active_readers_.Rotate();
+        current = active_readers_.head();
+      } while (current != root);
+    }
+    for (HashMap::Entry *entry = tokens_map_.Start();
+         entry != NULL;
+         entry = tokens_map_.Next(entry)) {
+      PortEntry* pentry = reinterpret_cast<PortEntry*>(entry->value);
+      if (pentry->IsReady()) {
+        ready_count--;
+      }
+    }
+    // Ensure all ready items are in `active_readers_`.
+    ASSERT(ready_count == 0);
+#endif
+
+    return was_empty && active_readers_.HasHead();
+  }
+
+  virtual bool RemovePort(Dart_Port port) {
+    HashMap::Entry* entry = tokens_map_.Lookup(
+        GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port), false);
+    if (entry != NULL) {
+      PortEntry* pentry = reinterpret_cast<PortEntry*>(entry->value);
+      if (pentry->IsReady()) {
+        active_readers_.Remove(pentry);
+      }
+      tokens_map_.Remove(
+          GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port));
+      delete pentry;
+    } else {
+      // NOTE: This is a listening socket which has been immediately closed.
+      //
+      // If a listening socket is not listened on, the event handler does not
+      // know about it beforehand. So the first time the event handler knows
+      // about it, is when it is supposed to be closed. We therefore do nothing
+      // here.
+      //
+      // But whether to close it, depends on whether other isolates have it open
+      // as well or not.
+    }
+    return !active_readers_.HasHead();
+  }
+
+  virtual Dart_Port NextPort() {
+    ASSERT(active_readers_.HasHead());
+    PortEntry* pentry = reinterpret_cast<PortEntry*>(active_readers_.head());
+    return pentry->dart_port;
+  }
+
+  virtual bool HasNextPort() {
+    return active_readers_.HasHead();
+  }
+
+  virtual void SendToAll(uintptr_t data) {
+    for (HashMap::Entry *entry = tokens_map_.Start();
+         entry != NULL;
+         entry = tokens_map_.Next(entry)) {
+      PortEntry* pentry = reinterpret_cast<PortEntry*>(entry->value);
+      DartUtils::PostInt32(pentry->dart_port, data);
+    }
+  }
+
+
+  virtual bool TakeToken() {
+    ASSERT(active_readers_.HasHead());
+    PortEntry* pentry = reinterpret_cast<PortEntry*>(active_readers_.head());
+    ASSERT(pentry->token_count > 0);
+    pentry->token_count--;
+    if (pentry->token_count == 0) {
+      active_readers_.RemoveHead();
+      return !active_readers_.HasHead();
+    } else {
+      active_readers_.Rotate();
+      return false;
+    }
+  }
+
+  virtual bool ReturnTokens(Dart_Port port, int count) {
+    HashMap::Entry* entry = tokens_map_.Lookup(
+        GetHashmapKeyFromPort(port), GetHashmapHashFromPort(port), false);
+    ASSERT(entry != NULL);
+
+    PortEntry* pentry = reinterpret_cast<PortEntry*>(entry->value);
+    pentry->token_count += count;
+    if (pentry->token_count == count && pentry->IsReady()) {
+      bool was_empty = !active_readers_.HasHead();
+      active_readers_.Add(pentry);
+      return was_empty;
+    }
+    return false;
+  }
+
+  virtual bool HasTokens() const {
+    return active_readers_.HasHead();
+  }
+
+  virtual intptr_t Mask() {
+    if (active_readers_.HasHead()) {
+      return 1 << kInEvent;
+    }
+    return 0;
+  }
+
+  virtual void Close() {
+    SI::Close();
+  }
+
+ private:
+  // The [Dart_Port]s which are not paused (i.e. are interested in read events,
+  // i.e. `mask == (1 << kInEvent)`) and we have enough tokens to communicate
+  // with them.
+  CircularLinkedList<PortEntry *> active_readers_;
+
+  // A convenience mapping:
+  //   Dart_Port -> struct PortEntry { dart_port, mask, token_count }
+  HashMap tokens_map_;
+};
+
+
+class InterruptMessage {
+ public:
+  intptr_t id;
+  Dart_Port dart_port;
+  int64_t data;
+};
+
+
+static const int kInterruptMessageSize = sizeof(InterruptMessage);
+static const int kInfinityTimeout = -1;
+static const int kTimerId = -1;
+static const int kShutdownId = -2;
+
 }  // namespace bin
 }  // namespace dart