In RtpPacket do not keep pointer to RtpHeaderExtensionMap

webrtc/modules/rtp_rtcp/source/rtp_packet.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_packet.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_packet.cc b/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
index 72fd7892b235f1c1118b07457d18f87f9e83e1e7..b7d71c27898cbb8abf7e860e65736df6377eb125 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_packet.cc
@@ -52,26 +52,28 @@ constexpr size_t kDefaultPacketSize = 1500;
 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 // |               padding         | Padding size  |
 // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+Packet::Packet() : Packet(nullptr, kDefaultPacketSize) {}
+
 Packet::Packet(const ExtensionManager* extensions)
-    : extensions_(extensions), buffer_(kDefaultPacketSize) {
-  Clear();
-}
+    : Packet(extensions, kDefaultPacketSize) {}
 
 Packet::Packet(const ExtensionManager* extensions, size_t capacity)
-    : extensions_(extensions), buffer_(capacity) {
+    : buffer_(capacity) {
   RTC_DCHECK_GE(capacity, kFixedHeaderSize);
   Clear();
+  if (extensions) {
+    IdentifyExtensions(*extensions);
+  } else {
+    for (size_t i = 0; i < kMaxExtensionHeaders; ++i)
+      extension_entries_[i].type = ExtensionManager::kInvalidType;
+  }
 }
 
 Packet::~Packet() {}
 
-void Packet::IdentifyExtensions(const ExtensionManager* extensions) {
-  RTC_DCHECK(extensions);
-  extensions_ = extensions;
-  for (size_t i = 0; i < num_extensions_; ++i) {
-    uint8_t id = data()[extension_entries_[i].offset - 1] >> 4;
-    extension_entries_[i].type = extensions_->GetType(id);
-  }
+void Packet::IdentifyExtensions(const ExtensionManager& extensions) {
+  for (size_t i = 0; i < kMaxExtensionHeaders; ++i)
+    extension_entries_[i].type = extensions.GetType(i + 1);
 }
 
 bool Packet::Parse(const uint8_t* buffer, size_t buffer_size) {
@@ -211,8 +213,7 @@ void Packet::CopyHeaderFrom(const Packet& packet) {
   timestamp_ = packet.timestamp_;
   ssrc_ = packet.ssrc_;
   payload_offset_ = packet.payload_offset_;
-  num_extensions_ = packet.num_extensions_;
-  for (size_t i = 0; i < num_extensions_; ++i) {
+  for (size_t i = 0; i < kMaxExtensionHeaders; ++i) {
     extension_entries_[i] = packet.extension_entries_[i];
   }
   extensions_size_ = packet.extensions_size_;
@@ -253,7 +254,7 @@ void Packet::SetSsrc(uint32_t ssrc) {
 }
 
 void Packet::SetCsrcs(const std::vector<uint32_t>& csrcs) {
-  RTC_DCHECK_EQ(num_extensions_, 0);
+  RTC_DCHECK_EQ(extensions_size_, 0);
   RTC_DCHECK_EQ(payload_size_, 0);
   RTC_DCHECK_EQ(padding_size_, 0);
   RTC_DCHECK_LE(csrcs.size(), 0x0fu);
@@ -322,8 +323,11 @@ void Packet::Clear() {
   payload_offset_ = kFixedHeaderSize;
   payload_size_ = 0;
   padding_size_ = 0;
-  num_extensions_ = 0;
   extensions_size_ = 0;
+  for (ExtensionInfo& location : extension_entries_) {
+    location.offset = 0;
+    location.length = 0;
+  }
 
   memset(WriteAt(0), 0, kFixedHeaderSize);
   buffer_.SetSize(kFixedHeaderSize);
@@ -362,8 +366,11 @@ bool Packet::ParseBuffer(const uint8_t* buffer, size_t size) {
     padding_size_ = 0;
   }
 
-  num_extensions_ = 0;
   extensions_size_ = 0;
+  for (ExtensionInfo& location : extension_entries_) {
+    location.offset = 0;
+    location.length = 0;
+  }
   if (has_extension) {
     /* RTP header extension, RFC 3550.
      0                   1                   2                   3
@@ -392,7 +399,7 @@ bool Packet::ParseBuffer(const uint8_t* buffer, size_t size) {
       constexpr uint8_t kPaddingId = 0;
       constexpr uint8_t kReservedId = 15;
       while (extensions_size_ + kOneByteHeaderSize < extensions_capacity) {
-        uint8_t id = buffer[extension_offset + extensions_size_] >> 4;
+        int id = buffer[extension_offset + extensions_size_] >> 4;
         if (id == kReservedId) {
           break;
         } else if (id == kPaddingId) {
@@ -406,18 +413,16 @@ bool Packet::ParseBuffer(const uint8_t* buffer, size_t size) {
           LOG(LS_WARNING) << "Oversized rtp header extension.";
           break;
         }
-        if (num_extensions_ >= kMaxExtensionHeaders) {
-          LOG(LS_WARNING) << "Too many rtp header extensions.";
-          break;
+
+        size_t idx = id - 1;
+        if (extension_entries_[idx].length != 0) {
+          LOG(LS_VERBOSE) << "Duplicate rtp header extension id " << id
+                          << ". Overwriting.";
         }
+
         extensions_size_ += kOneByteHeaderSize;
-        extension_entries_[num_extensions_].type =
-            extensions_ ? extensions_->GetType(id)
-                        : ExtensionManager::kInvalidType;
-        extension_entries_[num_extensions_].length = length;
-        extension_entries_[num_extensions_].offset =
-            extension_offset + extensions_size_;
-        num_extensions_++;
+        extension_entries_[idx].offset = extension_offset + extensions_size_;
+        extension_entries_[idx].length = length;
         extensions_size_ += length;
       }
     }
@@ -435,16 +440,19 @@ bool Packet::FindExtension(ExtensionType type,
                            uint8_t length,
                            uint16_t* offset) const {
   RTC_DCHECK(offset);
-  for (size_t i = 0; i < num_extensions_; ++i) {
-    if (extension_entries_[i].type == type) {
-      if (length != extension_entries_[i].length) {
+  for (const ExtensionInfo& extension : extension_entries_) {
+    if (extension.type == type) {
+      if (extension.length == 0) {
+        // Extension is registered but not set.
+        return false;
+      }
+      if (length != extension.length) {
         LOG(LS_WARNING) << "Length mismatch for extension '" << type
                         << "': expected " << static_cast<int>(length)
-                        << ", received "
-                        << static_cast<int>(extension_entries_[i].length);
+                        << ", received " << static_cast<int>(extension.length);
         return false;
       }
-      *offset = extension_entries_[i].offset;
+      *offset = extension.offset;
       return true;
     }
   }
@@ -454,10 +462,28 @@ bool Packet::FindExtension(ExtensionType type,
 bool Packet::AllocateExtension(ExtensionType type,
                                uint8_t length,
                                uint16_t* offset) {
-  if (!extensions_) {
-    return false;
+  uint8_t extension_id = ExtensionManager::kInvalidId;
+  ExtensionInfo* extension_entry = nullptr;
+  for (size_t i = 0; i < kMaxExtensionHeaders; ++i) {
+    if (extension_entries_[i].type == type) {
+      extension_id = i + 1;
+      extension_entry = &extension_entries_[i];
+      break;
+    }
   }
-  if (FindExtension(type, length, offset)) {
+
+  if (!extension_entry)  // Extension not registered.
+    return false;
+
+  if (extension_entry->length != 0) {  // Already allocated.
+    if (length != extension_entry->length) {
+      LOG(LS_WARNING) << "Length mismatch for extension '" << type
+                      << "': expected " << static_cast<int>(length)
+                      << ", received "
+                      << static_cast<int>(extension_entry->length);
+      return false;
+    }
+    *offset = extension_entry->offset;
     return true;
   }
 
@@ -469,10 +495,6 @@ bool Packet::AllocateExtension(ExtensionType type,
     return false;
   }
 
-  uint8_t extension_id = extensions_->GetId(type);
-  if (extension_id == ExtensionManager::kInvalidId) {
-    return false;
-  }
   RTC_DCHECK_GT(length, 0);
   RTC_DCHECK_LE(length, 16);
 
@@ -491,9 +513,8 @@ bool Packet::AllocateExtension(ExtensionType type,
       (new_extensions_size + 3) / 4;  // Wrap up to 32bit.
 
   // All checks passed, write down the extension.
-  if (num_extensions_ == 0) {
+  if (extensions_size_ == 0) {
     RTC_DCHECK_EQ(payload_offset_, kFixedHeaderSize + (num_csrc * 4));
-    RTC_DCHECK_EQ(extensions_size_, 0);
     WriteAt(0, data()[0] | 0x10);  // Set extension bit.
     // Profile specific ID always set to OneByteExtensionHeader.
     ByteWriter<uint16_t>::WriteBigEndian(WriteAt(extensions_offset - 4),
@@ -502,12 +523,10 @@ bool Packet::AllocateExtension(ExtensionType type,
 
   WriteAt(extensions_offset + extensions_size_,
           (extension_id << 4) | (length - 1));
-  RTC_DCHECK(num_extensions_ < kMaxExtensionHeaders);
-  extension_entries_[num_extensions_].type = type;
-  extension_entries_[num_extensions_].length = length;
+
+  extension_entry->length = length;
   *offset = extensions_offset + kOneByteHeaderSize + extensions_size_;
-  extension_entries_[num_extensions_].offset = *offset;
-  ++num_extensions_;
+  extension_entry->offset = *offset;
   extensions_size_ = new_extensions_size;
 
   // Update header length field.