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