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Diffstat (limited to 'mojo/edk/system/handle_table.h')
-rw-r--r-- | mojo/edk/system/handle_table.h | 144 |
1 files changed, 0 insertions, 144 deletions
diff --git a/mojo/edk/system/handle_table.h b/mojo/edk/system/handle_table.h deleted file mode 100644 index 9385643..0000000 --- a/mojo/edk/system/handle_table.h +++ /dev/null @@ -1,144 +0,0 @@ -// Copyright 2014 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -#ifndef MOJO_EDK_SYSTEM_HANDLE_TABLE_H_ -#define MOJO_EDK_SYSTEM_HANDLE_TABLE_H_ - -#include <utility> -#include <vector> - -#include "base/containers/hash_tables.h" -#include "base/macros.h" -#include "base/memory/ref_counted.h" -#include "mojo/edk/system/system_impl_export.h" -#include "mojo/public/c/system/types.h" - -namespace mojo { -namespace system { - -class Core; -class Dispatcher; -class DispatcherTransport; - -typedef std::vector<scoped_refptr<Dispatcher>> DispatcherVector; - -// Test-only function (defined/used in embedder/test_embedder.cc). Declared here -// so it can be friended. -namespace internal { -bool ShutdownCheckNoLeaks(Core*); -} - -// This class provides the (global) handle table (owned by |Core|), which maps -// (valid) |MojoHandle|s to |Dispatcher|s. This is abstracted so that, e.g., -// caching may be added. -// -// This class is NOT thread-safe; locking is left to |Core| (since it may need -// to make several changes -- "atomically" or in rapid successsion, in which -// case the extra locking/unlocking would be unnecessary overhead). - -class MOJO_SYSTEM_IMPL_EXPORT HandleTable { - public: - HandleTable(); - ~HandleTable(); - - // Gets the dispatcher for a given handle (which should not be - // |MOJO_HANDLE_INVALID|). Returns null if there's no dispatcher for the given - // handle. - // WARNING: For efficiency, this returns a dumb pointer. If you're going to - // use the result outside |Core|'s lock, you MUST take a reference (e.g., by - // storing the result inside a |scoped_refptr|). - Dispatcher* GetDispatcher(MojoHandle handle); - - // On success, gets the dispatcher for a given handle (which should not be - // |MOJO_HANDLE_INVALID|) and removes it. (On failure, returns an appropriate - // result (and leaves |dispatcher| alone), namely - // |MOJO_RESULT_INVALID_ARGUMENT| if there's no dispatcher for the given - // handle or |MOJO_RESULT_BUSY| if the handle is marked as busy.) - MojoResult GetAndRemoveDispatcher(MojoHandle handle, - scoped_refptr<Dispatcher>* dispatcher); - - // Adds a dispatcher (which must be valid), returning the handle for it. - // Returns |MOJO_HANDLE_INVALID| on failure (if the handle table is full). - MojoHandle AddDispatcher(const scoped_refptr<Dispatcher>& dispatcher); - - // Adds a pair of dispatchers (which must be valid), return a pair of handles - // for them. On failure (if the handle table is full), the first (and second) - // handles will be |MOJO_HANDLE_INVALID|, and neither dispatcher will be - // added. - std::pair<MojoHandle, MojoHandle> AddDispatcherPair( - const scoped_refptr<Dispatcher>& dispatcher0, - const scoped_refptr<Dispatcher>& dispatcher1); - - // Adds the given vector of dispatchers (of size at most - // |kMaxMessageNumHandles|). |handles| must point to an array of size at least - // |dispatchers.size()|. Unlike the other |AddDispatcher...()| functions, some - // of the dispatchers may be invalid (null). Returns true on success and false - // on failure (if the handle table is full), in which case it leaves - // |handles[...]| untouched (and all dispatchers unadded). - bool AddDispatcherVector(const DispatcherVector& dispatchers, - MojoHandle* handles); - - // Tries to mark the given handles as busy and start transport on them (i.e., - // take their dispatcher locks); |transports| must be sized to contain - // |num_handles| elements. On failure, returns them to their original - // (non-busy, unlocked state). - MojoResult MarkBusyAndStartTransport( - MojoHandle disallowed_handle, - const MojoHandle* handles, - uint32_t num_handles, - std::vector<DispatcherTransport>* transports); - - // Remove the given handles, which must all be present and which should have - // previously been marked busy by |MarkBusyAndStartTransport()|. - void RemoveBusyHandles(const MojoHandle* handles, uint32_t num_handles); - - // Restores the given handles, which must all be present and which should have - // previously been marked busy by |MarkBusyAndStartTransport()|, to a non-busy - // state. - void RestoreBusyHandles(const MojoHandle* handles, uint32_t num_handles); - - private: - friend bool internal::ShutdownCheckNoLeaks(Core*); - - // The |busy| member is used only to deal with functions (in particular - // |Core::WriteMessage()|) that want to hold on to a dispatcher and later - // remove it from the handle table, without holding on to the handle table - // lock. - // - // For example, if |Core::WriteMessage()| is called with a handle to be sent, - // (under the handle table lock) it must first check that that handle is not - // busy (if it is busy, then it fails with |MOJO_RESULT_BUSY|) and then marks - // it as busy. To avoid deadlock, it should also try to acquire the locks for - // all the dispatchers for the handles that it is sending (and fail with - // |MOJO_RESULT_BUSY| if the attempt fails). At this point, it can release the - // handle table lock. - // - // If |Core::Close()| is simultaneously called on that handle, it too checks - // if the handle is marked busy. If it is, it fails (with |MOJO_RESULT_BUSY|). - // This prevents |Core::WriteMessage()| from sending a handle that has been - // closed (or learning about this too late). - struct Entry { - Entry(); - explicit Entry(const scoped_refptr<Dispatcher>& dispatcher); - ~Entry(); - - scoped_refptr<Dispatcher> dispatcher; - bool busy; - }; - typedef base::hash_map<MojoHandle, Entry> HandleToEntryMap; - - // Adds the given dispatcher to the handle table, not doing any size checks. - MojoHandle AddDispatcherNoSizeCheck( - const scoped_refptr<Dispatcher>& dispatcher); - - HandleToEntryMap handle_to_entry_map_; - MojoHandle next_handle_; // Invariant: never |MOJO_HANDLE_INVALID|. - - DISALLOW_COPY_AND_ASSIGN(HandleTable); -}; - -} // namespace system -} // namespace mojo - -#endif // MOJO_EDK_SYSTEM_HANDLE_TABLE_H_ |