Simplify and extend RtpHeaderExtensionMap

webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc b/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
index 7fdff3498532ad43aef92592cafc94f463371b6d..b7c73062759df159f35ecbfc2b01646307db1331 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_header_extension.cc
@@ -8,148 +8,143 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include <assert.h>
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extension.h"
 
+#include "webrtc/base/arraysize.h"
 #include "webrtc/base/checks.h"
-#include "webrtc/common_types.h"
-#include "webrtc/modules/rtp_rtcp/source/rtp_header_extension.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
 
 namespace webrtc {
+namespace {
 
-constexpr uint8_t RtpHeaderExtensionMap::kInvalidId;
+using RtpUtility::Word32Align;
 
-RtpHeaderExtensionMap::RtpHeaderExtensionMap() {
+struct ExtensionInfo {
+  RTPExtensionType type;
+  size_t value_size;
+  const char* uri;
+};
+
+template <typename Extension>
+constexpr ExtensionInfo CreateExtensionInfo() {
+  return {Extension::kId, Extension::kValueSizeBytes, Extension::kUri};
 }
 
-RtpHeaderExtensionMap::~RtpHeaderExtensionMap() {
-  Erase();
+constexpr ExtensionInfo kExtensions[] = {
+    CreateExtensionInfo<TransmissionOffset>(),
+    CreateExtensionInfo<AudioLevel>(),
+    CreateExtensionInfo<AbsoluteSendTime>(),
+    CreateExtensionInfo<VideoOrientation>(),
+    CreateExtensionInfo<TransportSequenceNumber>(),
+    CreateExtensionInfo<PlayoutDelayLimits>(),
+};
+
+// Because of kRtpExtensionNone, NumberOfExtension is 1 bigger than the actual
+// number of known extensions.
+static_assert(arraysize(kExtensions) ==
+                  static_cast<int>(kRtpExtensionNumberOfExtensions) - 1,
+              "kExtensions expect to list all known extensions");
+
+size_t ValueSize(RTPExtensionType type) {
+  for (const ExtensionInfo& extension : kExtensions)
+    if (type == extension.type)
+      return extension.value_size;
+
+  RTC_NOTREACHED();
+  return 0;
 }
 
-void RtpHeaderExtensionMap::Erase() {
-  while (!extensionMap_.empty()) {
-    std::map<uint8_t, HeaderExtension*>::iterator it =
-        extensionMap_.begin();
-    delete it->second;
-    extensionMap_.erase(it);
-  }
+}  // namespace
+
+constexpr RTPExtensionType RtpHeaderExtensionMap::kInvalidType;
+constexpr uint8_t RtpHeaderExtensionMap::kInvalidId;
+constexpr uint8_t RtpHeaderExtensionMap::kMinId;
+constexpr uint8_t RtpHeaderExtensionMap::kMaxId;
+
+RtpHeaderExtensionMap::RtpHeaderExtensionMap() {
+  total_values_size_bytes_ = 0;
+  for (auto& type : types_)
+    type = kInvalidType;
+  for (auto& id : ids_)
+    id = kInvalidId;
 }
 
-int32_t RtpHeaderExtensionMap::Register(RTPExtensionType type, uint8_t id) {
-  if (id < 1 || id > 14) {
-    return -1;
-  }
-  std::map<uint8_t, HeaderExtension*>::iterator it =
-      extensionMap_.find(id);
-  if (it != extensionMap_.end()) {
-    if (it->second->type != type) {
-      // An extension is already registered with the same id
-      // but a different type, so return failure.
-      return -1;
-    }
-    // This extension type is already registered with this id,
-    // so return success.
-    return 0;
-  }
-  RTC_DCHECK_EQ(kInvalidId, GetId(type));
-  extensionMap_[id] = new HeaderExtension(type);
-  return 0;
+RtpHeaderExtensionMap::RtpHeaderExtensionMap(
+    std::initializer_list<RtpExtension> extensions)
+    : RtpHeaderExtensionMap() {
+  for (const RtpExtension& extension : extensions)
+    RegisterByUri(extension.id, extension.uri);
 }
 
-int32_t RtpHeaderExtensionMap::Deregister(const RTPExtensionType type) {
-  uint8_t id;
-  if (GetId(type, &id) != 0) {
-    return 0;
-  }
-  std::map<uint8_t, HeaderExtension*>::iterator it =
-      extensionMap_.find(id);
-  assert(it != extensionMap_.end());
-  delete it->second;
-  extensionMap_.erase(it);
-  return 0;
+bool RtpHeaderExtensionMap::RegisterByType(uint8_t id, RTPExtensionType type) {
+  for (const ExtensionInfo& extension : kExtensions)
+    if (type == extension.type)
+      return Register(id, extension.type, extension.value_size, extension.uri);
+  RTC_NOTREACHED();
+  return false;
 }
 
-bool RtpHeaderExtensionMap::IsRegistered(RTPExtensionType type) const {
-  std::map<uint8_t, HeaderExtension*>::const_iterator it =
-    extensionMap_.begin();
-  for (; it != extensionMap_.end(); ++it) {
-    if (it->second->type == type)
-      return true;
-  }
+bool RtpHeaderExtensionMap::RegisterByUri(uint8_t id, const std::string& uri) {
+  for (const ExtensionInfo& extension : kExtensions)
+    if (uri == extension.uri)
+      return Register(id, extension.type, extension.value_size, extension.uri);
+  LOG(LS_WARNING) << "Unknown extension uri:'" << uri
+                  << "', id: " << static_cast<int>(id) << '.';
   return false;
 }
 
-int32_t RtpHeaderExtensionMap::GetType(const uint8_t id,
-                                       RTPExtensionType* type) const {
-  assert(type);
-  std::map<uint8_t, HeaderExtension*>::const_iterator it =
-      extensionMap_.find(id);
-  if (it == extensionMap_.end()) {
-    return -1;
-  }
-  HeaderExtension* extension = it->second;
-  *type = extension->type;
-  return 0;
+size_t RtpHeaderExtensionMap::GetTotalLengthInBytes() const {
+  if (total_values_size_bytes_ == 0)
+    return 0;
+  return Word32Align(kRtpOneByteHeaderLength + total_values_size_bytes_);
 }
 
-RTPExtensionType RtpHeaderExtensionMap::GetType(uint8_t id) const {
-  auto it = extensionMap_.find(id);
-  if (it == extensionMap_.end()) {
-    return kInvalidType;
+int32_t RtpHeaderExtensionMap::Deregister(RTPExtensionType type) {
+  if (IsRegistered(type)) {
+    uint8_t id = GetId(type);
+    total_values_size_bytes_ -= (ValueSize(type) + 1);
+    types_[id] = kInvalidType;
+    ids_[type] = kInvalidId;
   }
-  return it->second->type;
+  return 0;
 }
 
-int32_t RtpHeaderExtensionMap::GetId(const RTPExtensionType type,
-                                     uint8_t* id) const {
-  assert(id);
-  std::map<uint8_t, HeaderExtension*>::const_iterator it =
-      extensionMap_.begin();
-
-  while (it != extensionMap_.end()) {
-    HeaderExtension* extension = it->second;
-    if (extension->type == type) {
-      *id = it->first;
-      return 0;
-    }
-    it++;
+bool RtpHeaderExtensionMap::Register(uint8_t id,
+                                     RTPExtensionType type,
+                                     size_t value_size,
+                                     const char* uri) {
+  RTC_DCHECK_GT(type, kRtpExtensionNone);
+  RTC_DCHECK_LT(type, kRtpExtensionNumberOfExtensions);
+  RTC_DCHECK_GE(value_size, 1U);
+  RTC_DCHECK_LE(value_size, 16U);
+
+  if (id < kMinId || id > kMaxId) {
+    LOG(LS_WARNING) << "Failed to register extension uri:'" << uri
+                    << "' with invalid id:" << static_cast<int>(id) << ".";
+    return false;
   }
-  return -1;
-}
 
-uint8_t RtpHeaderExtensionMap::GetId(RTPExtensionType type) const {
-  for (auto kv : extensionMap_) {
-    if (kv.second->type == type)
-      return kv.first;
+  if (GetType(id) == type) {  // Same type/id pair already registered.
+    LOG(LS_VERBOSE) << "Reregistering extension uri:'" << uri
+                    << "', id:" << static_cast<int>(id);
+    return true;
   }
-  return kInvalidId;
-}
 
-size_t RtpHeaderExtensionMap::GetTotalLengthInBytes() const {
-  // Get length for each extension block.
-  size_t length = 0;
-  for (const auto& kv : extensionMap_)
-    length += kv.second->length;
-  // Add RTP extension header length.
-  if (length > 0)
-    length += kRtpOneByteHeaderLength;
-  // Pad up to nearest 32bit word.
-  length = RtpUtility::Word32Align(length);
-  return length;
-}
+  if (GetType(id) != kInvalidType) {  // |id| used by another extension type.
+    LOG(LS_WARNING) << "Failed to register extension uri:'" << uri
+                    << "', id:" << static_cast<int>(id)
+                    << ". Id already in use by extension type "
+                    << static_cast<int>(GetType(id));
+    return false;
+  }
+  RTC_DCHECK(!IsRegistered(type));
 
-int32_t RtpHeaderExtensionMap::Size() const {
-  return extensionMap_.size();
+  types_[id] = type;
+  ids_[type] = id;
+  total_values_size_bytes_ += (value_size + 1);
+  return true;
 }
 
-void RtpHeaderExtensionMap::GetCopy(RtpHeaderExtensionMap* map) const {
-  assert(map);
-  std::map<uint8_t, HeaderExtension*>::const_iterator it =
-      extensionMap_.begin();
-  while (it != extensionMap_.end()) {
-    HeaderExtension* extension = it->second;
-    map->Register(extension->type, it->first);
-    it++;
-  }
-}
 }  // namespace webrtc