michael@0: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "sandbox/win/src/shared_handles.h"
michael@0: 
michael@0: namespace sandbox {
michael@0: 
michael@0: // Note once again the the assumption here is that the shared memory is
michael@0: // initialized with zeros in the process that calls SetHandle and that
michael@0: // the process that calls GetHandle 'sees' this memory.
michael@0: 
michael@0: SharedHandles::SharedHandles() {
michael@0:   shared_.items = NULL;
michael@0:   shared_.max_items = 0;
michael@0: }
michael@0: 
michael@0: bool SharedHandles::Init(void* raw_mem, size_t size_bytes) {
michael@0:   if (size_bytes < sizeof(shared_.items[0])) {
michael@0:     // The shared memory is too small!
michael@0:     return false;
michael@0:   }
michael@0:   shared_.items = static_cast<SharedItem*>(raw_mem);
michael@0:   shared_.max_items = size_bytes / sizeof(shared_.items[0]);
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: // Note that an empty slot is marked with a tag == 0 that is why is
michael@0: // not a valid imput tag
michael@0: bool SharedHandles::SetHandle(uint32 tag, HANDLE handle) {
michael@0:   if (0 == tag) {
michael@0:     // Invalid tag
michael@0:     return false;
michael@0:   }
michael@0:   // Find empty slot and put the tag and the handle there
michael@0:   SharedItem* empty_slot = FindByTag(0);
michael@0:   if (NULL == empty_slot) {
michael@0:     return false;
michael@0:   }
michael@0:   empty_slot->tag = tag;
michael@0:   empty_slot->item = handle;
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: bool SharedHandles::GetHandle(uint32 tag, HANDLE* handle) {
michael@0:   if (0 == tag) {
michael@0:     // Invalid tag
michael@0:     return false;
michael@0:   }
michael@0:   SharedItem* found = FindByTag(tag);
michael@0:   if (NULL == found) {
michael@0:     return false;
michael@0:   }
michael@0:   *handle = found->item;
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: SharedHandles::SharedItem* SharedHandles::FindByTag(uint32 tag) {
michael@0:   for (size_t ix = 0; ix != shared_.max_items; ++ix) {
michael@0:     if (tag == shared_.items[ix].tag) {
michael@0:       return &shared_.items[ix];
michael@0:     }
michael@0:   }
michael@0:   return NULL;
michael@0: }
michael@0: 
michael@0: }  // namespace sandbox