commit 3f6ccf498cd56a4693a9f5b3a5486a383c24a157
author dschinazi <dschinazi@google.com> Fri Oct 25 16:58:37 2019 -0700
committer Copybara-Service <copybara-worker@google.com> Fri Oct 25 16:59:09 2019 -0700
tree 56bed34ee2f0048f3a4b216d989a89f348623ba5
parent eab9285e406ec8eaef54a36652c8f4d469390b6d

Inline trivial constructors

I was investigating a Chromium merge failure where an unused variable triggered a warning in Chromium but not google3: cl/276485378. It appears that in google3 the compiler will only flag unused variables if they are primitive types, or if the struct/class has an inline constexpr constructor. So I performed a quick audit of our code and made the most obvious examples follow this pattern.

gfe-relnote: inline constructors, no behavior change
PiperOrigin-RevId: 276787382
Change-Id: Ib59b54d390b0e89966d2a8ccac2f4d1eaa478893

quic/core/quic_packet_number.h

diff --git a/quic/core/quic_packet_number.h b/quic/core/quic_packet_number.h
index 066d49c..8a75149 100644
--- a/quic/core/quic_packet_number.h
+++ b/quic/core/quic_packet_number.h
@@ -21,10 +21,15 @@
 class QUIC_EXPORT_PRIVATE QuicPacketNumber {
  public:
   // Construct an uninitialized packet number.
-  QuicPacketNumber();
+  constexpr QuicPacketNumber() : packet_number_(UninitializedPacketNumber()) {}
+
   // Construct a packet number from uint64_t. |packet_number| cannot equal the
   // sentinel value.
-  explicit QuicPacketNumber(uint64_t packet_number);
+  explicit constexpr QuicPacketNumber(uint64_t packet_number)
+      : packet_number_(packet_number) {
+    DCHECK_NE(UninitializedPacketNumber(), packet_number)
+        << "Use default constructor for uninitialized packet number";
+  }
 
   // Packet number becomes uninitialized after calling this function.
   void Clear();
@@ -80,7 +85,9 @@
   friend inline uint64_t operator-(QuicPacketNumber lhs, QuicPacketNumber rhs);
 
   // The sentinel value representing an uninitialized packet number.
-  static uint64_t UninitializedPacketNumber();
+  static constexpr uint64_t UninitializedPacketNumber() {
+    return std::numeric_limits<uint64_t>::max();
+  }
 
   uint64_t packet_number_;
 };