Support per-thread zones and stack resources.

runtime/vm/thread_registry.h

Index: runtime/vm/thread_registry.h
diff --git a/runtime/vm/thread_registry.h b/runtime/vm/thread_registry.h
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+++ b/runtime/vm/thread_registry.h
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+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_THREAD_REGISTRY_H_
+#define VM_THREAD_REGISTRY_H_
+
+#include "vm/globals.h"
+#include "vm/growable_array.h"
+#include "vm/isolate.h"
+#include "vm/lockers.h"
+#include "vm/thread.h"
+
+namespace dart {
+
+// Unordered collection of threads relating to a particular isolate.
+class ThreadRegistry {
+ public:
+  ThreadRegistry() : mutex_(), entries_() {}
+
+  bool RestoreStateTo(Thread* thread, Thread::State* state) {
+    MutexLocker ml(&mutex_);
+    Entry* entry = FindEntry(thread);
+    if (entry != NULL) {
+      Thread::State st = entry->state;
+      // TODO(koda): Support same thread re-entering same isolate with
+      // Dart frames in between. For now, just assert it doesn't happen.
+      if (st.top_exit_frame_info != thread->top_exit_frame_info()) {
+        ASSERT(thread->top_exit_frame_info() == 0 ||
+               thread->top_exit_frame_info() > st.top_exit_frame_info);
+      }
+      ASSERT(!entry->scheduled);
+      entry->scheduled = true;
+#if defined(DEBUG)
+      // State field is not in use, so zap it.
+      memset(&entry->state, 0xda, sizeof(entry->state));
+#endif
+      *state = st;
+      return true;
+    }
+    Entry new_entry;
+    new_entry.thread = thread;
+    new_entry.scheduled = true;
+#if defined(DEBUG)
+    // State field is not in use, so zap it.
+    memset(&new_entry.state, 0xda, sizeof(new_entry.state));
+#endif
+    entries_.Add(new_entry);
+    return false;
+  }
+
+  void SaveStateFrom(Thread* thread, const Thread::State& state) {
+    MutexLocker ml(&mutex_);
+    Entry* entry = FindEntry(thread);
+    ASSERT(entry != NULL);
+    ASSERT(entry->scheduled);
+    entry->scheduled = false;
+    entry->state = state;
+  }
+
+  bool Contains(Thread* thread) {
+    MutexLocker ml(&mutex_);
+    return (FindEntry(thread) != NULL);
+  }
+
+  void VisitObjectPointers(ObjectPointerVisitor* visitor) {
+    MutexLocker ml(&mutex_);
+    for (int i = 0; i < entries_.length(); ++i) {
+      const Entry& entry = entries_[i];
+      Zone* zone = entry.scheduled ? entry.thread->zone() : entry.state.zone;
+      if (zone != NULL) {
+        zone->VisitObjectPointers(visitor);
+      }
+    }
+  }
+
+ private:
+  struct Entry {
+    Thread* thread;
+    bool scheduled;
+    Thread::State state;
+  };
+
+  // Returns Entry corresponding to thread in registry or NULL.
+  // Note: Lock should be taken before this function is called.
+  Entry* FindEntry(Thread* thread) {
+    DEBUG_ASSERT(mutex_.IsOwnedByCurrentThread());
+    for (int i = 0; i < entries_.length(); ++i) {
+      if (entries_[i].thread == thread) {
+        return &entries_[i];
+      }
+    }
+    return NULL;
+  }
+
+  Mutex mutex_;
+  MallocGrowableArray<Entry> entries_;
+
+
+  DISALLOW_COPY_AND_ASSIGN(ThreadRegistry);
+};
+
+}  // namespace dart
+
+#endif  // VM_THREAD_REGISTRY_H_