1 files changed, 185 insertions, 0 deletions
diff --git a/o3d/command_buffer/client/cross/cmd_buffer_helper.cc b/o3d/command_buffer/client/cross/cmd_buffer_helper.cc
new file mode 100644
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+++ b/o3d/command_buffer/client/cross/cmd_buffer_helper.cc
@@ -0,0 +1,185 @@
+/*
+ * Copyright 2009, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+// This file contains the implementation of the command buffer helper class.
+
+#include "command_buffer/client/cross/cmd_buffer_helper.h"
+
+namespace o3d {
+namespace command_buffer {
+
+CommandBufferHelper::CommandBufferHelper(BufferSyncInterface *interface)
+    : interface_(interface),
+      entries_(NULL),
+      entry_count_(0),
+      token_(0) {
+  // The interface should be connected already.
+  DCHECK_NE(BufferSyncInterface::NOT_CONNECTED, interface_->GetStatus());
+}
+
+bool CommandBufferHelper::Init(unsigned int entry_count) {
+  if (entry_count == 0)
+    return false;
+  size_t size = entry_count * sizeof(CommandBufferEntry);  // NOLINT
+  shm_handle_ = CreateShm(size);
+  if (shm_handle_ == kRPCInvalidHandle)
+    return false;
+  void *address = MapShm(shm_handle_, size);
+  if (!address) {
+    DestroyShm(shm_handle_);
+    shm_handle_ = kRPCInvalidHandle;
+    return false;
+  }
+  entries_ = static_cast<CommandBufferEntry *>(address);
+  entry_count_ = entry_count;
+  shm_id_ = interface_->RegisterSharedMemory(shm_handle_, size);
+  interface_->SetCommandBuffer(shm_id_, 0, size, 0);
+  get_ = interface_->Get();
+  put_ = get_;
+  last_token_read_ = interface_->GetToken();
+  return true;
+}
+
+CommandBufferHelper::~CommandBufferHelper() {
+  if (entries_) {
+    interface_->UnregisterSharedMemory(shm_id_);
+    UnmapShm(entries_, entry_count_ * sizeof(CommandBufferEntry));  // NOLINT
+    DestroyShm(shm_handle_);
+  }
+}
+
+// Calls Flush() and then waits until the buffer is empty. Break early if the
+// error is set.
+void CommandBufferHelper::Finish() {
+  Flush();
+  while (put_ != get_) {
+    WaitForGetChange();
+  }
+}
+
+// Inserts a new token into the command stream. It uses an increasing value
+// scheme so that we don't lose tokens (a token has passed if the current token
+// value is higher than that token). Calls Finish() if the token value wraps,
+// which will be rare.
+unsigned int CommandBufferHelper::InsertToken() {
+  ++token_;
+  CommandBufferEntry args;
+  args.value_uint32 = token_;
+  AddCommand(SET_TOKEN, 1, &args);
+  if (token_ == 0) {
+    // we wrapped
+    Finish();
+    last_token_read_ = interface_->GetToken();
+    DCHECK_EQ(token_, last_token_read_);
+  }
+  return token_;
+}
+
+// Waits until the current token value is greater or equal to the value passed
+// in argument.
+void CommandBufferHelper::WaitForToken(unsigned int token) {
+  if (last_token_read_ >= token) return;  // fast path.
+  if (token > token_) return;  // we wrapped
+  Flush();
+  last_token_read_ = interface_->GetToken();
+  while (last_token_read_ < token) {
+    if (get_ == put_) {
+      LOG(FATAL) << "Empty command buffer while waiting on a token.";
+      return;
+    }
+    WaitForGetChange();
+    last_token_read_ = interface_->GetToken();
+  }
+}
+
+// Waits for get to change. In case get doesn't change or becomes invalid,
+// check for an error.
+void CommandBufferHelper::WaitForGetChange() {
+  CommandBufferOffset new_get = interface_->WaitGetChanges(get_);
+  if (new_get == get_ || new_get == -1) {
+    // If get_ didn't change or is invalid (-1), it means an error may have
+    // occured. Check that.
+    BufferSyncInterface::ParserStatus status = interface_->GetStatus();
+    if (status != BufferSyncInterface::PARSING) {
+      switch (status) {
+        case BufferSyncInterface::NOT_CONNECTED:
+          LOG(FATAL) << "Service disconnected.";
+          return;
+        case BufferSyncInterface::NO_BUFFER:
+          LOG(FATAL) << "Service doesn't have a buffer set.";
+          return;
+        case BufferSyncInterface::PARSE_ERROR: {
+          BufferSyncInterface::ParseError error = interface_->GetParseError();
+          LOG(WARNING) << "Parse error: " << error;
+          return;
+        }
+        case BufferSyncInterface::PARSING:
+          break;
+      }
+    }
+  }
+  get_ = new_get;
+}
+
+// Waits for available entries, basically waiting until get >= put + count + 1.
+// It actually waits for contiguous entries, so it may need to wrap the buffer
+// around, adding noops. Thus this function may change the value of put_.
+// The function will return early if an error occurs, in which case the
+// available space may not be available.
+void CommandBufferHelper::WaitForAvailableEntries(unsigned int count) {
+  CHECK(count < entry_count_);
+  if (put_ + count > entry_count_) {
+    // There's not enough room between the current put and the end of the
+    // buffer, so we need to wrap. We will add noops all the way to the end,
+    // but we need to make sure get wraps first, actually that get is 1 or
+    // more (since put will wrap to 0 after we add the noops).
+    DCHECK_LE(1, put_);
+    Flush();
+    while (get_ > put_ || get_ == 0) WaitForGetChange();
+    // Add the noops. By convention, a noop is a command 0 with no args.
+    CommandHeader header;
+    header.size = 1;
+    header.command = 0;
+    while (put_ < entry_count_) {
+      entries_[put_++].value_header = header;
+    }
+    put_ = 0;
+  }
+  // If we have enough room, return immediatly.
+  if (count <= AvailableEntries()) return;
+  // Otherwise flush, and wait until we do have enough room.
+  Flush();
+  while (AvailableEntries() < count) WaitForGetChange();
+}
+
+}  // namespace command_buffer
+}  // namespace o3d