1a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian/* 2a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * Copyright (C) 2010 The Android Open Source Project 3a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * 4a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * Licensed under the Apache License, Version 2.0 (the "License"); 5a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * you may not use this file except in compliance with the License. 6a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * You may obtain a copy of the License at 7a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * 8a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * http://www.apache.org/licenses/LICENSE-2.0 9a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * 10a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * Unless required by applicable law or agreed to in writing, software 11a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * distributed under the License is distributed on an "AS IS" BASIS, 12a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * See the License for the specific language governing permissions and 14a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian * limitations under the License. 15a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian */ 16a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 17a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian#ifndef ANDROID_UTILS_FLATTENABLE_H 18a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian#define ANDROID_UTILS_FLATTENABLE_H 19a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 20a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 21a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian#include <stdint.h> 222ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell#include <string.h> 23a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian#include <sys/types.h> 24a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian#include <utils/Errors.h> 256d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian#include <utils/Debug.h> 26a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 272ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell#include <type_traits> 282ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell 29a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopiannamespace android { 30a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 316d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 326d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianclass FlattenableUtils { 336d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianpublic: 341811d156e9c6b5486d25090ec3e911632dc6edffColin Cross template<size_t N> 356d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian static size_t align(size_t size) { 366d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian COMPILE_TIME_ASSERT_FUNCTION_SCOPE( !(N & (N-1)) ); 376d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return (size + (N-1)) & ~(N-1); 386d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian } 396d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 401811d156e9c6b5486d25090ec3e911632dc6edffColin Cross template<size_t N> 41ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian static size_t align(void const*& buffer) { 426d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian COMPILE_TIME_ASSERT_FUNCTION_SCOPE( !(N & (N-1)) ); 431811d156e9c6b5486d25090ec3e911632dc6edffColin Cross uintptr_t b = uintptr_t(buffer); 441811d156e9c6b5486d25090ec3e911632dc6edffColin Cross buffer = reinterpret_cast<void*>((uintptr_t(buffer) + (N-1)) & ~(N-1)); 451811d156e9c6b5486d25090ec3e911632dc6edffColin Cross return size_t(uintptr_t(buffer) - b); 466d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian } 476d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 481811d156e9c6b5486d25090ec3e911632dc6edffColin Cross template<size_t N> 49ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian static size_t align(void*& buffer) { 50ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian return align<N>( const_cast<void const*&>(buffer) ); 51ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian } 52ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian 536d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian static void advance(void*& buffer, size_t& size, size_t offset) { 541811d156e9c6b5486d25090ec3e911632dc6edffColin Cross buffer = reinterpret_cast<void*>( uintptr_t(buffer) + offset ); 556d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian size -= offset; 566d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian } 576d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 586d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian static void advance(void const*& buffer, size_t& size, size_t offset) { 591811d156e9c6b5486d25090ec3e911632dc6edffColin Cross buffer = reinterpret_cast<void const*>( uintptr_t(buffer) + offset ); 606d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian size -= offset; 616d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian } 626d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 636d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian // write a POD structure 646d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian template<typename T> 656d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian static void write(void*& buffer, size_t& size, const T& value) { 662ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell static_assert(std::is_trivially_copyable<T>::value, 672ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell "Cannot flatten a non-trivially-copyable type"); 682ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell memcpy(buffer, &value, sizeof(T)); 696d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian advance(buffer, size, sizeof(T)); 706d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian } 716d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 726d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian // read a POD structure 736d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian template<typename T> 746d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian static void read(void const*& buffer, size_t& size, T& value) { 752ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell static_assert(std::is_trivially_copyable<T>::value, 762ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell "Cannot unflatten a non-trivially-copyable type"); 772ebce7384bc7bc6c31122096326c9384d09bdce1David Pursell memcpy(&value, buffer, sizeof(T)); 786d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian advance(buffer, size, sizeof(T)); 796d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian } 806d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian}; 816d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 826d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 832497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian/* 846d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian * The Flattenable protocol allows an object to serialize itself out 852497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian * to a byte-buffer and an array of file descriptors. 866d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian * Flattenable objects must implement this protocol. 872497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian */ 882497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 896d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopiantemplate <typename T> 906d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianclass Flattenable { 91a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopianpublic: 92a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // size in bytes of the flattened object 936d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian inline size_t getFlattenedSize() const; 94a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 95a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // number of file descriptors to flatten 966d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian inline size_t getFdCount() const; 97a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 98a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // flattens the object into buffer. 99a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // size should be at least of getFlattenedSize() 100a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // file descriptors are written in the fds[] array but ownership is 101a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // not transfered (ie: they must be dupped by the caller of 102a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // flatten() if needed). 103ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian inline status_t flatten(void*& buffer, size_t& size, int*& fds, size_t& count) const; 104a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 105a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // unflattens the object from buffer. 106a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // size should be equal to the value of getFlattenedSize() when the 107a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // object was flattened. 108a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // unflattened file descriptors are found in the fds[] array and 109a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // don't need to be dupped(). ie: the caller of unflatten doesn't 110a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // keep ownership. If a fd is not retained by unflatten() it must be 111a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian // explicitly closed. 112ddff6230495b66312ad93f652d0c79069a64dbbdMathias Agopian inline status_t unflatten(void const*& buffer, size_t& size, int const*& fds, size_t& count); 113a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian}; 114a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 1156d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopiantemplate<typename T> 1166d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianinline size_t Flattenable<T>::getFlattenedSize() const { 1176d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return static_cast<T const*>(this)->T::getFlattenedSize(); 1186d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian} 1196d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopiantemplate<typename T> 1206d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianinline size_t Flattenable<T>::getFdCount() const { 1216d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return static_cast<T const*>(this)->T::getFdCount(); 1226d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian} 1236d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopiantemplate<typename T> 1246d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianinline status_t Flattenable<T>::flatten( 1256d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian void*& buffer, size_t& size, int*& fds, size_t& count) const { 1266d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return static_cast<T const*>(this)->T::flatten(buffer, size, fds, count); 1276d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian} 1286d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopiantemplate<typename T> 1296d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianinline status_t Flattenable<T>::unflatten( 1306d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian void const*& buffer, size_t& size, int const*& fds, size_t& count) { 1316d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return static_cast<T*>(this)->T::unflatten(buffer, size, fds, count); 1326d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian} 1336d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian 1342497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian/* 1352497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian * LightFlattenable is a protocol allowing object to serialize themselves out 1366d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian * to a byte-buffer. Because it doesn't handle file-descriptors, 1376d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian * LightFlattenable is usually more size efficient than Flattenable. 1382497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian * LightFlattenable objects must implement this protocol. 1392497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian */ 1402497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopiantemplate <typename T> 1412497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopianclass LightFlattenable { 1422497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopianpublic: 1432497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian // returns whether this object always flatten into the same size. 1442497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian // for efficiency, this should always be inline. 1452497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian inline bool isFixedSize() const; 1462497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 1472497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian // returns size in bytes of the flattened object. must be a constant. 1486d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian inline size_t getFlattenedSize() const; 1492497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 1502497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian // flattens the object into buffer. 1516d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian inline status_t flatten(void* buffer, size_t size) const; 1522497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 1532497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian // unflattens the object from buffer of given size. 1542497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian inline status_t unflatten(void const* buffer, size_t size); 1552497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian}; 1562497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 1572497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopiantemplate <typename T> 1582497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopianinline bool LightFlattenable<T>::isFixedSize() const { 1592497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian return static_cast<T const*>(this)->T::isFixedSize(); 1602497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian} 1612497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopiantemplate <typename T> 1626d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianinline size_t LightFlattenable<T>::getFlattenedSize() const { 1636d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return static_cast<T const*>(this)->T::getFlattenedSize(); 1642497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian} 1652497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopiantemplate <typename T> 1666d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopianinline status_t LightFlattenable<T>::flatten(void* buffer, size_t size) const { 1676d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian return static_cast<T const*>(this)->T::flatten(buffer, size); 1682497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian} 1692497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopiantemplate <typename T> 1702497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopianinline status_t LightFlattenable<T>::unflatten(void const* buffer, size_t size) { 1712497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian return static_cast<T*>(this)->T::unflatten(buffer, size); 1722497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian} 1732497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 1742497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian/* 1752497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian * LightFlattenablePod is an implementation of the LightFlattenable protocol 1762497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian * for POD (plain-old-data) objects. 1776d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian * Simply derive from LightFlattenablePod<Foo> to make Foo flattenable; no 1786d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian * need to implement any methods; obviously Foo must be a POD structure. 1792497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian */ 1802497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopiantemplate <typename T> 1812497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopianclass LightFlattenablePod : public LightFlattenable<T> { 1822497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopianpublic: 1832497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian inline bool isFixedSize() const { 1842497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian return true; 1852497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian } 1862497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 1876d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian inline size_t getFlattenedSize() const { 1882497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian return sizeof(T); 1892497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian } 1906d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian inline status_t flatten(void* buffer, size_t size) const { 1916d611a891d0c818bf3a34a7cad036f3f0064bc4aMathias Agopian if (size < sizeof(T)) return NO_MEMORY; 192c46cbcbbf9a4c23ab8887d8e4a364a14e63c2b1bChris Forbes memcpy(buffer, static_cast<T const*>(this), sizeof(T)); 1932497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian return NO_ERROR; 1942497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian } 1952497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian inline status_t unflatten(void const* buffer, size_t) { 196c46cbcbbf9a4c23ab8887d8e4a364a14e63c2b1bChris Forbes memcpy(static_cast<T*>(this), buffer, sizeof(T)); 1972497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian return NO_ERROR; 1982497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian } 1992497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian}; 2002497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 2012497a1524dd909d0eb933544c94d2c2e9e2c3394Mathias Agopian 202a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian}; // namespace android 203a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 204a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian 205a580e68cc3bea688167eb5e55122bec8e83ab939Mathias Agopian#endif /* ANDROID_UTILS_FLATTENABLE_H */ 206