No compliation-flag-dependent members in CriticalSection

webrtc/base/criticalsection.cc

Index: webrtc/base/criticalsection.cc
diff --git a/webrtc/base/criticalsection.cc b/webrtc/base/criticalsection.cc
index b15bb82ef4fb40da3f96a476fe09fec23e5c1fb2..1756391f92518fa90c092698a2f10698e6e7dd8c 100644
--- a/webrtc/base/criticalsection.cc
+++ b/webrtc/base/criticalsection.cc
@@ -20,7 +20,7 @@ namespace rtc {
 CriticalSection::CriticalSection() {
 #if defined(WEBRTC_WIN)
   InitializeCriticalSection(&crit_);
-#else
+#elif defined(WEBRTC_POSIX)

[eladalon, 2017/06/26 12:35:22]

mutex_ does not really exist otherwise; would be a compilation error if we ever
have a non-WEBRTC_WIN build that's also not WEBRTC_POSIX. I don't know if that's
likely, but might as well have the structure here mimic that of the header.

So we have two options:
1. Change the header to not depend on WEBRTC_POSIX for this.
2. Change everywhere that mute_ is accessed, and make sure that WEBRTC_POSIX.

I prefer the second option. Wdyt?

[nisse-webrtc, 2017/06/26 12:53:09]

If you do it this way, also add an 

#else
#error Platform not supported
#endif

to not fail silently on unexpected platforms.

For the main question, I think the important thing is to get a clear compilation
error for unsupported platforms, but it doesn't matter very much if the the
message says "error unsupported platform" or "mutex_ is not defined".

[eladalon, 2017/06/26 13:38:12]

Added throughout the module.

 #if defined(WEBRTC_MAC) && !USE_NATIVE_MUTEX_ON_MAC
   lock_queue_ = 0;
   owning_thread_ = 0;
@@ -35,6 +35,8 @@ CriticalSection::CriticalSection() {
 #endif
   CS_DEBUG_CODE(thread_ = 0);
   CS_DEBUG_CODE(recursion_count_ = 0);
+  RTC_UNUSED(thread_);           // Depends on CS_DEBUG_CHECKS.

[nisse-webrtc, 2017/06/26 12:53:09]

Drop this comment. Instead, add a comment in the header saying that these member
variables are used for DCHECKs only.

[eladalon, 2017/06/26 13:38:12]

Done.

+  RTC_UNUSED(recursion_count_);  // Depends on CS_DEBUG_CHECKS.
 #endif
 }
 
@@ -186,6 +188,7 @@ CritScope::~CritScope() { cs_->Leave(); }
 TryCritScope::TryCritScope(const CriticalSection* cs)
     : cs_(cs), locked_(cs->TryEnter()) {
   CS_DEBUG_CODE(lock_was_called_ = false);
+  RTC_UNUSED(lock_was_called_);  // Depends on CS_DEBUG_CHECKS.
 }
 
 TryCritScope::~TryCritScope() {