15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/* Copyright (c) 2006, Google Inc. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * All rights reserved. 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Redistribution and use in source and binary forms, with or without 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * modification, are permitted provided that the following conditions are 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * met: 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * * Redistributions of source code must retain the above copyright 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * notice, this list of conditions and the following disclaimer. 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * * Redistributions in binary form must reproduce the above 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * copyright notice, this list of conditions and the following disclaimer 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * in the documentation and/or other materials provided with the 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * distribution. 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * * Neither the name of Google Inc. nor the names of its 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * contributors may be used to endorse or promote products derived from 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * this software without specific prior written permission. 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#if !defined(_BASE_LOW_LEVEL_ALLOC_H_) 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define _BASE_LOW_LEVEL_ALLOC_H_ 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A simple thread-safe memory allocator that does not depend on 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// mutexes or thread-specific data. It is intended to be used 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// sparingly, and only when malloc() would introduce an unwanted 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// dependency, such as inside the heap-checker. 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <config.h> 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <stddef.h> // for size_t 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/basictypes.h" 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class LowLevelAlloc { 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) struct Arena; // an arena from which memory may be allocated 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns a pointer to a block of at least "request" bytes 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // that have been newly allocated from the specific arena. 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // for Alloc() call the DefaultArena() is used. 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns 0 if passed request==0. 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Does not return 0 under other circumstances; it crashes if memory 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // is not available. 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void *Alloc(size_t request) 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ATTRIBUTE_SECTION(malloc_hook); 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void *AllocWithArena(size_t request, Arena *arena) 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ATTRIBUTE_SECTION(malloc_hook); 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Deallocates a region of memory that was previously allocated with 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Alloc(). Does nothing if passed 0. "s" must be either 0, 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // or must have been returned from a call to Alloc() and not yet passed to 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Free() since that call to Alloc(). The space is returned to the arena 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // from which it was allocated. 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void Free(void *s) ATTRIBUTE_SECTION(malloc_hook); 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // ATTRIBUTE_SECTION(malloc_hook) for Alloc* and Free 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // are to put all callers of MallocHook::Invoke* in this module 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // into special section, 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // so that MallocHook::GetCallerStackTrace can function accurately. 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Create a new arena. 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The root metadata for the new arena is allocated in the 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // meta_data_arena; the DefaultArena() can be passed for meta_data_arena. 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // These values may be ored into flags: 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) enum { 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Report calls to Alloc() and Free() via the MallocHook interface. 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Set in the DefaultArena. 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) kCallMallocHook = 0x0001, 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Make calls to Alloc(), Free() be async-signal-safe. Not set in 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // DefaultArena(). 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) kAsyncSignalSafe = 0x0002, 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // When used with DefaultArena(), the NewArena() and DeleteArena() calls 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // obey the flags given explicitly in the NewArena() call, even if those 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // flags differ from the settings in DefaultArena(). So the call 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // NewArena(kAsyncSignalSafe, DefaultArena()) is itself async-signal-safe, 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // as well as generatating an arena that provides async-signal-safe 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Alloc/Free. 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) }; 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static Arena *NewArena(int32 flags, Arena *meta_data_arena); 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Destroys an arena allocated by NewArena and returns true, 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // provided no allocated blocks remain in the arena. 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If allocated blocks remain in the arena, does nothing and 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // returns false. 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // It is illegal to attempt to destroy the DefaultArena(). 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static bool DeleteArena(Arena *arena); 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The default arena that always exists. 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static Arena *DefaultArena(); 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) LowLevelAlloc(); // no instances 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif 107