Add m-esr52 at 52.6.0

1 files changed, 577 insertions, 0 deletions

diff --git a/xpcom/glue/nsTHashtable.h b/xpcom/glue/nsTHashtable.h
new file mode 100644
index 000000000..705b0294e
--- /dev/null
+++ b/xpcom/glue/nsTHashtable.h
@@ -0,0 +1,577 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsTHashtable_h__
+#define nsTHashtable_h__
+
+#include "PLDHashTable.h"
+#include "nsPointerHashKeys.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/fallible.h"
+#include "mozilla/MemoryChecking.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/Move.h"
+#include "mozilla/OperatorNewExtensions.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/TypeTraits.h"
+
+#include <new>
+
+/**
+ * a base class for templated hashtables.
+ *
+ * Clients will rarely need to use this class directly. Check the derived
+ * classes first, to see if they will meet your needs.
+ *
+ * @param EntryType  the templated entry-type class that is managed by the
+ *   hashtable. <code>EntryType</code> must extend the following declaration,
+ *   and <strong>must not declare any virtual functions or derive from classes
+ *   with virtual functions.</strong>  Any vtable pointer would break the
+ *   PLDHashTable code.
+ *<pre>   class EntryType : public PLDHashEntryHdr
+ *   {
+ *   public: or friend nsTHashtable<EntryType>;
+ *     // KeyType is what we use when Get()ing or Put()ing this entry
+ *     // this should either be a simple datatype (uint32_t, nsISupports*) or
+ *     // a const reference (const nsAString&)
+ *     typedef something KeyType;
+ *     // KeyTypePointer is the pointer-version of KeyType, because
+ *     // PLDHashTable.h requires keys to cast to <code>const void*</code>
+ *     typedef const something* KeyTypePointer;
+ *
+ *     EntryType(KeyTypePointer aKey);
+ *
+ *     // A copy or C++11 Move constructor must be defined, even if
+ *     // AllowMemMove() == true, otherwise you will cause link errors.
+ *     EntryType(const EntryType& aEnt);  // Either this...
+ *     EntryType(EntryType&& aEnt);       // ...or this
+ *
+ *     // the destructor must be defined... or you will cause link errors!
+ *     ~EntryType();
+ *
+ *     // KeyEquals(): does this entry match this key?
+ *     bool KeyEquals(KeyTypePointer aKey) const;
+ *
+ *     // KeyToPointer(): Convert KeyType to KeyTypePointer
+ *     static KeyTypePointer KeyToPointer(KeyType aKey);
+ *
+ *     // HashKey(): calculate the hash number
+ *     static PLDHashNumber HashKey(KeyTypePointer aKey);
+ *
+ *     // ALLOW_MEMMOVE can we move this class with memmove(), or do we have
+ *     // to use the copy constructor?
+ *     enum { ALLOW_MEMMOVE = true/false };
+ *   }</pre>
+ *
+ * @see nsInterfaceHashtable
+ * @see nsDataHashtable
+ * @see nsClassHashtable
+ * @author "Benjamin Smedberg <bsmedberg@covad.net>"
+ */
+
+template<class EntryType>
+class MOZ_NEEDS_NO_VTABLE_TYPE nsTHashtable
+{
+  typedef mozilla::fallible_t fallible_t;
+  static_assert(mozilla::IsPointer<typename EntryType::KeyTypePointer>::value,
+                "KeyTypePointer should be a pointer");
+
+public:
+  // Separate constructors instead of default aInitLength parameter since
+  // otherwise the default no-arg constructor isn't found.
+  nsTHashtable()
+    : mTable(Ops(), sizeof(EntryType), PLDHashTable::kDefaultInitialLength)
+  {}
+  explicit nsTHashtable(uint32_t aInitLength)
+    : mTable(Ops(), sizeof(EntryType), aInitLength)
+  {}
+
+  /**
+   * destructor, cleans up and deallocates
+   */
+  ~nsTHashtable();
+
+  nsTHashtable(nsTHashtable<EntryType>&& aOther);
+
+  /**
+   * Return the generation number for the table. This increments whenever
+   * the table data items are moved.
+   */
+  uint32_t GetGeneration() const { return mTable.Generation(); }
+
+  /**
+   * KeyType is typedef'ed for ease of use.
+   */
+  typedef typename EntryType::KeyType KeyType;
+
+  /**
+   * KeyTypePointer is typedef'ed for ease of use.
+   */
+  typedef typename EntryType::KeyTypePointer KeyTypePointer;
+
+  /**
+   * Return the number of entries in the table.
+   * @return    number of entries
+   */
+  uint32_t Count() const { return mTable.EntryCount(); }
+
+  /**
+   * Return true if the hashtable is empty.
+   */
+  bool IsEmpty() const { return Count() == 0; }
+
+  /**
+   * Get the entry associated with a key.
+   * @param     aKey the key to retrieve
+   * @return    pointer to the entry class, if the key exists; nullptr if the
+   *            key doesn't exist
+   */
+  EntryType* GetEntry(KeyType aKey) const
+  {
+    return static_cast<EntryType*>(
+      const_cast<PLDHashTable*>(&mTable)->Search(EntryType::KeyToPointer(aKey)));
+  }
+
+  /**
+   * Return true if an entry for the given key exists, false otherwise.
+   * @param     aKey the key to retrieve
+   * @return    true if the key exists, false if the key doesn't exist
+   */
+  bool Contains(KeyType aKey) const { return !!GetEntry(aKey); }
+
+  /**
+   * Get the entry associated with a key, or create a new entry,
+   * @param     aKey the key to retrieve
+   * @return    pointer to the entry class retreived; nullptr only if memory
+                can't be allocated
+   */
+  EntryType* PutEntry(KeyType aKey)
+  {
+    // infallible add
+    return static_cast<EntryType*>(mTable.Add(EntryType::KeyToPointer(aKey)));
+  }
+
+  MOZ_MUST_USE
+  EntryType* PutEntry(KeyType aKey, const fallible_t&)
+  {
+    return static_cast<EntryType*>(mTable.Add(EntryType::KeyToPointer(aKey),
+                                              mozilla::fallible));
+  }
+
+  /**
+   * Remove the entry associated with a key.
+   * @param     aKey of the entry to remove
+   */
+  void RemoveEntry(KeyType aKey)
+  {
+    mTable.Remove(EntryType::KeyToPointer(aKey));
+  }
+
+  /**
+   * Remove the entry associated with a key.
+   * @param aEntry   the entry-pointer to remove (obtained from GetEntry)
+   */
+  void RemoveEntry(EntryType* aEntry)
+  {
+    mTable.RemoveEntry(aEntry);
+  }
+
+  /**
+   * Remove the entry associated with a key, but don't resize the hashtable.
+   * This is a low-level method, and is not recommended unless you know what
+   * you're doing. If you use it, please add a comment explaining why you
+   * didn't use RemoveEntry().
+   * @param aEntry   the entry-pointer to remove (obtained from GetEntry)
+   */
+  void RawRemoveEntry(EntryType* aEntry)
+  {
+    mTable.RawRemove(aEntry);
+  }
+
+  // This is an iterator that also allows entry removal. Example usage:
+  //
+  //   for (auto iter = table.Iter(); !iter.Done(); iter.Next()) {
+  //     Entry* entry = iter.Get();
+  //     // ... do stuff with |entry| ...
+  //     // ... possibly call iter.Remove() once ...
+  //   }
+  //
+  class Iterator : public PLDHashTable::Iterator
+  {
+  public:
+    typedef PLDHashTable::Iterator Base;
+
+    explicit Iterator(nsTHashtable* aTable) : Base(&aTable->mTable) {}
+    Iterator(Iterator&& aOther) : Base(aOther.mTable) {}
+    ~Iterator() {}
+
+    EntryType* Get() const { return static_cast<EntryType*>(Base::Get()); }
+
+  private:
+    Iterator() = delete;
+    Iterator(const Iterator&) = delete;
+    Iterator& operator=(const Iterator&) = delete;
+    Iterator& operator=(const Iterator&&) = delete;
+  };
+
+  Iterator Iter() { return Iterator(this); }
+
+  Iterator ConstIter() const
+  {
+    return Iterator(const_cast<nsTHashtable*>(this));
+  }
+
+  /**
+   * Remove all entries, return hashtable to "pristine" state. It's
+   * conceptually the same as calling the destructor and then re-calling the
+   * constructor.
+   */
+  void Clear()
+  {
+    mTable.Clear();
+  }
+
+  /**
+   * Measure the size of the table's entry storage. Does *not* measure anything
+   * hanging off table entries; hence the "Shallow" prefix. To measure that,
+   * either use SizeOfExcludingThis() or iterate manually over the entries,
+   * calling SizeOfExcludingThis() on each one.
+   *
+   * @param     aMallocSizeOf the function used to measure heap-allocated blocks
+   * @return    the measured shallow size of the table
+   */
+  size_t ShallowSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    return mTable.ShallowSizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  /**
+   * Like ShallowSizeOfExcludingThis, but includes sizeof(*this).
+   */
+  size_t ShallowSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    return aMallocSizeOf(this) + ShallowSizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  /**
+   * This is a "deep" measurement of the table. To use it, |EntryType| must
+   * define SizeOfExcludingThis, and that method will be called on all live
+   * entries.
+   */
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    size_t n = ShallowSizeOfExcludingThis(aMallocSizeOf);
+    for (auto iter = ConstIter(); !iter.Done(); iter.Next()) {
+      n += (*iter.Get()).SizeOfExcludingThis(aMallocSizeOf);
+    }
+    return n;
+  }
+
+  /**
+   * Like SizeOfExcludingThis, but includes sizeof(*this).
+   */
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+  {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  /**
+   * Swap the elements in this hashtable with the elements in aOther.
+   */
+  void SwapElements(nsTHashtable<EntryType>& aOther)
+  {
+    MOZ_ASSERT_IF(this->mTable.Ops() && aOther.mTable.Ops(),
+                  this->mTable.Ops() == aOther.mTable.Ops());
+    mozilla::Swap(this->mTable, aOther.mTable);
+  }
+
+#ifdef DEBUG
+  /**
+   * Mark the table as constant after initialization.
+   *
+   * This will prevent assertions when a read-only hash is accessed on multiple
+   * threads without synchronization.
+   */
+  void MarkImmutable()
+  {
+    mTable.MarkImmutable();
+  }
+#endif
+
+protected:
+  PLDHashTable mTable;
+
+  static PLDHashNumber s_HashKey(const void* aKey);
+
+  static bool s_MatchEntry(const PLDHashEntryHdr* aEntry,
+                           const void* aKey);
+
+  static void s_CopyEntry(PLDHashTable* aTable, const PLDHashEntryHdr* aFrom,
+                          PLDHashEntryHdr* aTo);
+
+  static void s_ClearEntry(PLDHashTable* aTable, PLDHashEntryHdr* aEntry);
+
+  static void s_InitEntry(PLDHashEntryHdr* aEntry, const void* aKey);
+
+private:
+  // copy constructor, not implemented
+  nsTHashtable(nsTHashtable<EntryType>& aToCopy) = delete;
+
+  /**
+   * Gets the table's ops.
+   */
+  static const PLDHashTableOps* Ops();
+
+  // assignment operator, not implemented
+  nsTHashtable<EntryType>& operator=(nsTHashtable<EntryType>& aToEqual) = delete;
+};
+
+//
+// template definitions
+//
+
+template<class EntryType>
+nsTHashtable<EntryType>::nsTHashtable(nsTHashtable<EntryType>&& aOther)
+  : mTable(mozilla::Move(aOther.mTable))
+{
+  // aOther shouldn't touch mTable after this, because we've stolen the table's
+  // pointers but not overwitten them.
+  MOZ_MAKE_MEM_UNDEFINED(&aOther.mTable, sizeof(aOther.mTable));
+}
+
+template<class EntryType>
+nsTHashtable<EntryType>::~nsTHashtable()
+{
+}
+
+template<class EntryType>
+/* static */ const PLDHashTableOps*
+nsTHashtable<EntryType>::Ops()
+{
+  // If this variable is a global variable, we get strange start-up failures on
+  // WindowsCrtPatch.h (see bug 1166598 comment 20). But putting it inside a
+  // function avoids that problem.
+  static const PLDHashTableOps sOps =
+  {
+    s_HashKey,
+    s_MatchEntry,
+    EntryType::ALLOW_MEMMOVE ? PLDHashTable::MoveEntryStub : s_CopyEntry,
+    s_ClearEntry,
+    s_InitEntry
+  };
+  return &sOps;
+}
+
+// static definitions
+
+template<class EntryType>
+PLDHashNumber
+nsTHashtable<EntryType>::s_HashKey(const void* aKey)
+{
+  return EntryType::HashKey(static_cast<const KeyTypePointer>(aKey));
+}
+
+template<class EntryType>
+bool
+nsTHashtable<EntryType>::s_MatchEntry(const PLDHashEntryHdr* aEntry,
+                                      const void* aKey)
+{
+  return ((const EntryType*)aEntry)->KeyEquals(
+    static_cast<const KeyTypePointer>(aKey));
+}
+
+template<class EntryType>
+void
+nsTHashtable<EntryType>::s_CopyEntry(PLDHashTable* aTable,
+                                     const PLDHashEntryHdr* aFrom,
+                                     PLDHashEntryHdr* aTo)
+{
+  EntryType* fromEntry =
+    const_cast<EntryType*>(static_cast<const EntryType*>(aFrom));
+
+  new (mozilla::KnownNotNull, aTo) EntryType(mozilla::Move(*fromEntry));
+
+  fromEntry->~EntryType();
+}
+
+template<class EntryType>
+void
+nsTHashtable<EntryType>::s_ClearEntry(PLDHashTable* aTable,
+                                      PLDHashEntryHdr* aEntry)
+{
+  static_cast<EntryType*>(aEntry)->~EntryType();
+}
+
+template<class EntryType>
+void
+nsTHashtable<EntryType>::s_InitEntry(PLDHashEntryHdr* aEntry,
+                                     const void* aKey)
+{
+  new (mozilla::KnownNotNull, aEntry) EntryType(static_cast<KeyTypePointer>(aKey));
+}
+
+class nsCycleCollectionTraversalCallback;
+
+template<class EntryType>
+inline void
+ImplCycleCollectionUnlink(nsTHashtable<EntryType>& aField)
+{
+  aField.Clear();
+}
+
+template<class EntryType>
+inline void
+ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
+                            nsTHashtable<EntryType>& aField,
+                            const char* aName,
+                            uint32_t aFlags = 0)
+{
+  for (auto iter = aField.Iter(); !iter.Done(); iter.Next()) {
+    EntryType* entry = iter.Get();
+    ImplCycleCollectionTraverse(aCallback, *entry, aName, aFlags);
+  }
+}
+
+/**
+ * For nsTHashtable with pointer entries, we can have a template specialization
+ * that layers a typed T* interface on top of a common implementation that
+ * works internally with void pointers.  This arrangement saves code size and
+ * might slightly improve performance as well.
+ */
+
+/**
+ * We need a separate entry type class for the inheritance structure of the
+ * nsTHashtable specialization below; nsVoidPtrHashKey is simply typedefed to a
+ * specialization of nsPtrHashKey, and the formulation:
+ *
+ * class nsTHashtable<nsPtrHashKey<T>> : protected nsTHashtable<nsPtrHashKey<const void>
+ *
+ * is not going to turn out very well, since we'd wind up with an nsTHashtable
+ * instantiation that is its own base class.
+ */
+namespace detail {
+
+class VoidPtrHashKey : public nsPtrHashKey<const void>
+{
+  typedef nsPtrHashKey<const void> Base;
+
+public:
+  explicit VoidPtrHashKey(const void* aKey) : Base(aKey) {}
+};
+
+} // namespace detail
+
+/**
+ * See the main nsTHashtable documentation for descriptions of this class's
+ * methods.
+ */
+template<typename T>
+class nsTHashtable<nsPtrHashKey<T>> : protected nsTHashtable<::detail::VoidPtrHashKey>
+{
+  typedef nsTHashtable<::detail::VoidPtrHashKey> Base;
+  typedef nsPtrHashKey<T> EntryType;
+
+  // We play games with reinterpret_cast'ing between these two classes, so
+  // try to ensure that playing said games is reasonable.
+  static_assert(sizeof(nsPtrHashKey<T>) == sizeof(::detail::VoidPtrHashKey),
+                "hash keys must be the same size");
+
+  nsTHashtable(const nsTHashtable& aOther) = delete;
+  nsTHashtable& operator=(const nsTHashtable& aOther) = delete;
+
+public:
+  nsTHashtable() = default;
+  explicit nsTHashtable(uint32_t aInitLength)
+    : Base(aInitLength)
+  {}
+
+  ~nsTHashtable() = default;
+
+  nsTHashtable(nsTHashtable&&) = default;
+
+  /* Wrapper functions */
+  using Base::GetGeneration;
+  using Base::Count;
+  using Base::IsEmpty;
+  using Base::Clear;
+
+  using Base::ShallowSizeOfExcludingThis;
+  using Base::ShallowSizeOfIncludingThis;
+
+#ifdef DEBUG
+  using Base::MarkImmutable;
+#endif
+
+  EntryType* GetEntry(T* aKey) const
+  {
+    return reinterpret_cast<EntryType*>(Base::GetEntry(aKey));
+  }
+
+  bool Contains(T* aKey) const
+  {
+    return Base::Contains(aKey);
+  }
+
+  EntryType* PutEntry(T* aKey)
+  {
+    return reinterpret_cast<EntryType*>(Base::PutEntry(aKey));
+  }
+
+  MOZ_MUST_USE
+  EntryType* PutEntry(T* aKey, const mozilla::fallible_t&)
+  {
+    return reinterpret_cast<EntryType*>(
+      Base::PutEntry(aKey, mozilla::fallible));
+  }
+
+  void RemoveEntry(T* aKey)
+  {
+    Base::RemoveEntry(aKey);
+  }
+
+  void RemoveEntry(EntryType* aEntry)
+  {
+    Base::RemoveEntry(reinterpret_cast<::detail::VoidPtrHashKey*>(aEntry));
+  }
+
+  void RawRemoveEntry(EntryType* aEntry)
+  {
+    Base::RawRemoveEntry(reinterpret_cast<::detail::VoidPtrHashKey*>(aEntry));
+  }
+
+  class Iterator : public Base::Iterator
+  {
+  public:
+    typedef nsTHashtable::Base::Iterator Base;
+
+    explicit Iterator(nsTHashtable* aTable) : Base(aTable) {}
+    Iterator(Iterator&& aOther) : Base(mozilla::Move(aOther)) {}
+    ~Iterator() = default;
+
+    EntryType* Get() const { return reinterpret_cast<EntryType*>(Base::Get()); }
+
+  private:
+    Iterator() = delete;
+    Iterator(const Iterator&) = delete;
+    Iterator& operator=(const Iterator&) = delete;
+    Iterator& operator=(Iterator&&) = delete;
+  };
+
+  Iterator Iter() { return Iterator(this); }
+
+  Iterator ConstIter() const
+  {
+    return Iterator(const_cast<nsTHashtable*>(this));
+  }
+
+  void SwapElements(nsTHashtable& aOther)
+  {
+    Base::SwapElements(aOther);
+  }
+};
+
+#endif // nsTHashtable_h__