зеркало из https://github.com/mozilla/gecko-dev.git
101 строка
2.5 KiB
C++
101 строка
2.5 KiB
C++
/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_GFX_USERDATA_H_
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#define MOZILLA_GFX_USERDATA_H_
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#include <stdlib.h>
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#include "mozilla/Assertions.h"
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namespace mozilla {
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namespace gfx {
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struct UserDataKey {
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int unused;
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};
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/* this class is basically a clone of the user data concept from cairo */
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class UserData
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{
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typedef void (*destroyFunc)(void *data);
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public:
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UserData() : count(0), entries(NULL) {}
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/* Attaches untyped userData associated with key. destroy is called on destruction */
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void Add(UserDataKey *key, void *userData, destroyFunc destroy)
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{
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// XXX we should really warn if user data with key has already been added,
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// since in that case Get() will return the old user data!
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// We could keep entries in a std::vector instead of managing it by hand
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// but that would propagate an stl dependency out which we'd rather not
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// do (see bug 666609). Plus, the entries array is expect to stay small
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// so doing a realloc everytime we add a new entry shouldn't be too costly
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entries = static_cast<Entry*>(realloc(entries, sizeof(Entry)*(count+1)));
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if (!entries) {
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MOZ_CRASH();
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}
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entries[count].key = key;
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entries[count].userData = userData;
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entries[count].destroy = destroy;
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count++;
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}
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/* Remove and return user data associated with key, without destroying it */
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void* Remove(UserDataKey *key)
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{
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for (int i=0; i<count; i++) {
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if (key == entries[i].key) {
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void *userData = entries[i].userData;
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// decrement before looping so entries[i+1] doesn't read past the end:
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--count;
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for (;i<count; i++) {
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entries[i] = entries[i+1];
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}
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return userData;
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}
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}
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return NULL;
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}
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/* Retrives the userData for the associated key */
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void *Get(UserDataKey *key)
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{
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for (int i=0; i<count; i++) {
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if (key == entries[i].key) {
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return entries[i].userData;
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}
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}
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return NULL;
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}
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~UserData()
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{
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for (int i=0; i<count; i++) {
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entries[i].destroy(entries[i].userData);
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}
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free(entries);
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}
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private:
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struct Entry {
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const UserDataKey *key;
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void *userData;
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destroyFunc destroy;
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};
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int count;
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Entry *entries;
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};
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}
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}
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#endif /* MOZILLA_GFX_USERDATA_H_ */
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