Proxy: solve event tracing with compile time strings.
This change creates trace events with a single parameter
composed of ClassName::Method.
The change additionally causes the duration of the proxy call to be
traced, not only the occurrence.
Fixed: webrtc:12787
Change-Id: I1689862318d4c6fc1dcef343c3ccf3ae9f7e17df
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219788
Commit-Queue: Markus Handell <handellm@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34149}
diff --git a/pc/dtmf_sender.h b/pc/dtmf_sender.h
index cb515e8..b64b50e 100644
--- a/pc/dtmf_sender.h
+++ b/pc/dtmf_sender.h
@@ -102,7 +102,6 @@
// Define proxy for DtmfSenderInterface.
BEGIN_PRIMARY_PROXY_MAP(DtmfSender)
-
PROXY_PRIMARY_THREAD_DESTRUCTOR()
PROXY_METHOD1(void, RegisterObserver, DtmfSenderObserverInterface*)
PROXY_METHOD0(void, UnregisterObserver)
@@ -112,7 +111,7 @@
PROXY_CONSTMETHOD0(int, duration)
PROXY_CONSTMETHOD0(int, inter_tone_gap)
PROXY_CONSTMETHOD0(int, comma_delay)
-END_PROXY_MAP()
+END_PROXY_MAP(DtmfSender)
// Get DTMF code from the DTMF event character.
bool GetDtmfCode(char tone, int* code);
diff --git a/pc/media_stream_proxy.h b/pc/media_stream_proxy.h
index b2d4443..36069a4 100644
--- a/pc/media_stream_proxy.h
+++ b/pc/media_stream_proxy.h
@@ -37,7 +37,7 @@
PROXY_METHOD1(bool, RemoveTrack, VideoTrackInterface*)
PROXY_METHOD1(void, RegisterObserver, ObserverInterface*)
PROXY_METHOD1(void, UnregisterObserver, ObserverInterface*)
-END_PROXY_MAP()
+END_PROXY_MAP(MediaStream)
} // namespace webrtc
diff --git a/pc/media_stream_track_proxy.h b/pc/media_stream_track_proxy.h
index 1727799..f563137 100644
--- a/pc/media_stream_track_proxy.h
+++ b/pc/media_stream_track_proxy.h
@@ -37,7 +37,7 @@
PROXY_METHOD1(bool, set_enabled, bool)
PROXY_METHOD1(void, RegisterObserver, ObserverInterface*)
PROXY_METHOD1(void, UnregisterObserver, ObserverInterface*)
-END_PROXY_MAP()
+END_PROXY_MAP(AudioTrack)
BEGIN_PROXY_MAP(VideoTrack)
PROXY_PRIMARY_THREAD_DESTRUCTOR()
@@ -57,7 +57,7 @@
PROXY_METHOD1(void, RegisterObserver, ObserverInterface*)
PROXY_METHOD1(void, UnregisterObserver, ObserverInterface*)
-END_PROXY_MAP()
+END_PROXY_MAP(VideoTrack)
} // namespace webrtc
diff --git a/pc/peer_connection_factory_proxy.h b/pc/peer_connection_factory_proxy.h
index b257be7..59e373d 100644
--- a/pc/peer_connection_factory_proxy.h
+++ b/pc/peer_connection_factory_proxy.h
@@ -51,7 +51,7 @@
AudioSourceInterface*)
PROXY_SECONDARY_METHOD2(bool, StartAecDump, FILE*, int64_t)
PROXY_SECONDARY_METHOD0(void, StopAecDump)
-END_PROXY_MAP()
+END_PROXY_MAP(PeerConnectionFactory)
} // namespace webrtc
diff --git a/pc/peer_connection_proxy.h b/pc/peer_connection_proxy.h
index 212f619..7601c9d 100644
--- a/pc/peer_connection_proxy.h
+++ b/pc/peer_connection_proxy.h
@@ -157,7 +157,7 @@
PROXY_METHOD0(void, StopRtcEventLog)
PROXY_METHOD0(void, Close)
BYPASS_PROXY_CONSTMETHOD0(rtc::Thread*, signaling_thread)
-END_PROXY_MAP()
+END_PROXY_MAP(PeerConnection)
} // namespace webrtc
diff --git a/pc/proxy.cc b/pc/proxy.cc
index 7dc4786..5f4e0b8 100644
--- a/pc/proxy.cc
+++ b/pc/proxy.cc
@@ -14,8 +14,12 @@
namespace webrtc {
namespace proxy_internal {
-void TraceApiCall(const char* class_name, const char* method_name) {
- TRACE_EVENT1("webrtc", class_name, "method", method_name);
+ScopedTrace::ScopedTrace(const char* class_and_method_name)
+ : class_and_method_name_(class_and_method_name) {
+ TRACE_EVENT_BEGIN0("webrtc", class_and_method_name_);
+}
+ScopedTrace::~ScopedTrace() {
+ TRACE_EVENT_END0("webrtc", class_and_method_name_);
}
} // namespace proxy_internal
} // namespace webrtc
diff --git a/pc/proxy.h b/pc/proxy.h
index c4e4966..565ae80 100644
--- a/pc/proxy.h
+++ b/pc/proxy.h
@@ -71,16 +71,30 @@
#include "rtc_base/event.h"
#include "rtc_base/message_handler.h"
#include "rtc_base/ref_counted_object.h"
+#include "rtc_base/string_utils.h"
#include "rtc_base/system/rtc_export.h"
#include "rtc_base/thread.h"
+#if !defined(RTC_DISABLE_PROXY_TRACE_EVENTS) && !defined(WEBRTC_CHROMIUM_BUILD)
+#define RTC_DISABLE_PROXY_TRACE_EVENTS
+#endif
+
namespace rtc {
class Location;
}
namespace webrtc {
namespace proxy_internal {
-RTC_EXPORT void TraceApiCall(const char* class_name, const char* method_name);
+
+// Class for tracing the lifetime of MethodCall::Marshal.
+class ScopedTrace {
+ public:
+ explicit ScopedTrace(const char* class_and_method_name);
+ ~ScopedTrace();
+
+ private:
+ const char* const class_and_method_name_;
+};
} // namespace proxy_internal
template <typename R>
@@ -195,8 +209,8 @@
template <class INTERNAL_CLASS> \
class c##ProxyWithInternal : public c##Interface { \
protected: \
+ static constexpr char proxy_name_[] = #c "Proxy"; \
typedef c##Interface C; \
- const char* class_name_ = PROXY_STRINGIZE(c); \
\
public: \
const INTERNAL_CLASS* internal() const { return c_; } \
@@ -205,8 +219,10 @@
// clang-format off
// clang-format would put the semicolon alone,
// leading to a presubmit error (cpplint.py)
-#define END_PROXY_MAP() \
- };
+#define END_PROXY_MAP(c) \
+ }; \
+ template <class INTERNAL_CLASS> \
+ constexpr char c##ProxyWithInternal<INTERNAL_CLASS>::proxy_name_[];
// clang-format on
#define PRIMARY_PROXY_MAP_BOILERPLATE(c) \
@@ -306,53 +322,67 @@
\
public: // NOLINTNEXTLINE
-#define PROXY_METHOD0(r, method) \
- r method() override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r> call(c_, &C::method); \
- return call.Marshal(RTC_FROM_HERE, primary_thread_); \
+#if defined(RTC_DISABLE_PROXY_TRACE_EVENTS)
+#define TRACE_BOILERPLATE(method) \
+ do { \
+ } while (0)
+#else // if defined(RTC_DISABLE_PROXY_TRACE_EVENTS)
+#define TRACE_BOILERPLATE(method) \
+ static constexpr auto class_and_method_name = \
+ rtc::MakeCompileTimeString(proxy_name_) \
+ .Concat(rtc::MakeCompileTimeString("::")) \
+ .Concat(rtc::MakeCompileTimeString(#method)); \
+ proxy_internal::ScopedTrace scoped_trace(class_and_method_name.string)
+
+#endif // if defined(RTC_DISABLE_PROXY_TRACE_EVENTS)
+
+#define PROXY_METHOD0(r, method) \
+ r method() override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r> call(c_, &C::method); \
+ return call.Marshal(RTC_FROM_HERE, primary_thread_); \
}
-#define PROXY_CONSTMETHOD0(r, method) \
- r method() const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- ConstMethodCall<C, r> call(c_, &C::method); \
- return call.Marshal(RTC_FROM_HERE, primary_thread_); \
+#define PROXY_CONSTMETHOD0(r, method) \
+ r method() const override { \
+ TRACE_BOILERPLATE(method); \
+ ConstMethodCall<C, r> call(c_, &C::method); \
+ return call.Marshal(RTC_FROM_HERE, primary_thread_); \
}
-#define PROXY_METHOD1(r, method, t1) \
- r method(t1 a1) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
- return call.Marshal(RTC_FROM_HERE, primary_thread_); \
+#define PROXY_METHOD1(r, method, t1) \
+ r method(t1 a1) override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
+ return call.Marshal(RTC_FROM_HERE, primary_thread_); \
}
-#define PROXY_CONSTMETHOD1(r, method, t1) \
- r method(t1 a1) const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- ConstMethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
- return call.Marshal(RTC_FROM_HERE, primary_thread_); \
+#define PROXY_CONSTMETHOD1(r, method, t1) \
+ r method(t1 a1) const override { \
+ TRACE_BOILERPLATE(method); \
+ ConstMethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
+ return call.Marshal(RTC_FROM_HERE, primary_thread_); \
}
-#define PROXY_METHOD2(r, method, t1, t2) \
- r method(t1 a1, t2 a2) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
- std::move(a2)); \
- return call.Marshal(RTC_FROM_HERE, primary_thread_); \
+#define PROXY_METHOD2(r, method, t1, t2) \
+ r method(t1 a1, t2 a2) override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
+ std::move(a2)); \
+ return call.Marshal(RTC_FROM_HERE, primary_thread_); \
}
-#define PROXY_METHOD3(r, method, t1, t2, t3) \
- r method(t1 a1, t2 a2, t3 a3) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
- std::move(a2), std::move(a3)); \
- return call.Marshal(RTC_FROM_HERE, primary_thread_); \
+#define PROXY_METHOD3(r, method, t1, t2, t3) \
+ r method(t1 a1, t2 a2, t3 a3) override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
+ std::move(a2), std::move(a3)); \
+ return call.Marshal(RTC_FROM_HERE, primary_thread_); \
}
#define PROXY_METHOD4(r, method, t1, t2, t3, t4) \
r method(t1 a1, t2 a2, t3 a3, t4 a4) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
+ TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2, t3, t4> call(c_, &C::method, std::move(a1), \
std::move(a2), std::move(a3), \
std::move(a4)); \
@@ -361,7 +391,7 @@
#define PROXY_METHOD5(r, method, t1, t2, t3, t4, t5) \
r method(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
+ TRACE_BOILERPLATE(method); \
MethodCall<C, r, t1, t2, t3, t4, t5> call(c_, &C::method, std::move(a1), \
std::move(a2), std::move(a3), \
std::move(a4), std::move(a5)); \
@@ -369,61 +399,61 @@
}
// Define methods which should be invoked on the secondary thread.
-#define PROXY_SECONDARY_METHOD0(r, method) \
- r method() override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r> call(c_, &C::method); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_METHOD0(r, method) \
+ r method() override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r> call(c_, &C::method); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
-#define PROXY_SECONDARY_CONSTMETHOD0(r, method) \
- r method() const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- ConstMethodCall<C, r> call(c_, &C::method); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_CONSTMETHOD0(r, method) \
+ r method() const override { \
+ TRACE_BOILERPLATE(method); \
+ ConstMethodCall<C, r> call(c_, &C::method); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
-#define PROXY_SECONDARY_METHOD1(r, method, t1) \
- r method(t1 a1) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_METHOD1(r, method, t1) \
+ r method(t1 a1) override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
-#define PROXY_SECONDARY_CONSTMETHOD1(r, method, t1) \
- r method(t1 a1) const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- ConstMethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_CONSTMETHOD1(r, method, t1) \
+ r method(t1 a1) const override { \
+ TRACE_BOILERPLATE(method); \
+ ConstMethodCall<C, r, t1> call(c_, &C::method, std::move(a1)); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
-#define PROXY_SECONDARY_METHOD2(r, method, t1, t2) \
- r method(t1 a1, t2 a2) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
- std::move(a2)); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_METHOD2(r, method, t1, t2) \
+ r method(t1 a1, t2 a2) override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
+ std::move(a2)); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
-#define PROXY_SECONDARY_CONSTMETHOD2(r, method, t1, t2) \
- r method(t1 a1, t2 a2) const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- ConstMethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
- std::move(a2)); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_CONSTMETHOD2(r, method, t1, t2) \
+ r method(t1 a1, t2 a2) const override { \
+ TRACE_BOILERPLATE(method); \
+ ConstMethodCall<C, r, t1, t2> call(c_, &C::method, std::move(a1), \
+ std::move(a2)); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
-#define PROXY_SECONDARY_METHOD3(r, method, t1, t2, t3) \
- r method(t1 a1, t2 a2, t3 a3) override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- MethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
- std::move(a2), std::move(a3)); \
- return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
+#define PROXY_SECONDARY_METHOD3(r, method, t1, t2, t3) \
+ r method(t1 a1, t2 a2, t3 a3) override { \
+ TRACE_BOILERPLATE(method); \
+ MethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
+ std::move(a2), std::move(a3)); \
+ return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
}
#define PROXY_SECONDARY_CONSTMETHOD3(r, method, t1, t2) \
r method(t1 a1, t2 a2, t3 a3) const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
+ TRACE_BOILERPLATE(method); \
ConstMethodCall<C, r, t1, t2, t3> call(c_, &C::method, std::move(a1), \
std::move(a2), std::move(a3)); \
return call.Marshal(RTC_FROM_HERE, secondary_thread_); \
@@ -432,10 +462,10 @@
// For use when returning purely const state (set during construction).
// Use with caution. This method should only be used when the return value will
// always be the same.
-#define BYPASS_PROXY_CONSTMETHOD0(r, method) \
- r method() const override { \
- proxy_internal::TraceApiCall(class_name_, PROXY_STRINGIZE(method)); \
- return c_->method(); \
+#define BYPASS_PROXY_CONSTMETHOD0(r, method) \
+ r method() const override { \
+ TRACE_BOILERPLATE(method); \
+ return c_->method(); \
}
} // namespace webrtc
diff --git a/pc/proxy_unittest.cc b/pc/proxy_unittest.cc
index 497c99a..ef3d97e 100644
--- a/pc/proxy_unittest.cc
+++ b/pc/proxy_unittest.cc
@@ -71,7 +71,7 @@
PROXY_SECONDARY_METHOD1(std::string, Method1, std::string)
PROXY_CONSTMETHOD1(std::string, ConstMethod1, std::string)
PROXY_SECONDARY_METHOD2(std::string, Method2, std::string, std::string)
-END_PROXY_MAP()
+END_PROXY_MAP(Fake)
// Preprocessor hack to get a proxy class a name different than FakeProxy.
#define FakeProxy FakeSignalingProxy
@@ -84,7 +84,7 @@
PROXY_METHOD1(std::string, Method1, std::string)
PROXY_CONSTMETHOD1(std::string, ConstMethod1, std::string)
PROXY_METHOD2(std::string, Method2, std::string, std::string)
-END_PROXY_MAP()
+END_PROXY_MAP(Fake)
#undef FakeProxy
class SignalingProxyTest : public ::testing::Test {
@@ -272,7 +272,7 @@
BEGIN_OWNED_PROXY_MAP(Foo)
PROXY_PRIMARY_THREAD_DESTRUCTOR()
PROXY_METHOD0(void, Bar)
-END_PROXY_MAP()
+END_PROXY_MAP(Foo)
class OwnedProxyTest : public ::testing::Test {
public:
diff --git a/pc/rtp_receiver_proxy.h b/pc/rtp_receiver_proxy.h
index 409612e..d4114e0 100644
--- a/pc/rtp_receiver_proxy.h
+++ b/pc/rtp_receiver_proxy.h
@@ -47,7 +47,7 @@
PROXY_SECONDARY_METHOD1(void,
SetDepacketizerToDecoderFrameTransformer,
rtc::scoped_refptr<FrameTransformerInterface>)
-END_PROXY_MAP()
+END_PROXY_MAP(RtpReceiver)
} // namespace webrtc
diff --git a/pc/rtp_sender_proxy.h b/pc/rtp_sender_proxy.h
index e23f57b..2f8fe2c 100644
--- a/pc/rtp_sender_proxy.h
+++ b/pc/rtp_sender_proxy.h
@@ -44,7 +44,7 @@
PROXY_METHOD1(void,
SetEncoderToPacketizerFrameTransformer,
rtc::scoped_refptr<FrameTransformerInterface>)
-END_PROXY_MAP()
+END_PROXY_MAP(RtpSender)
} // namespace webrtc
diff --git a/pc/rtp_transceiver.h b/pc/rtp_transceiver.h
index 3c7db95..6b1307b 100644
--- a/pc/rtp_transceiver.h
+++ b/pc/rtp_transceiver.h
@@ -310,7 +310,7 @@
PROXY_METHOD1(webrtc::RTCError,
SetOfferedRtpHeaderExtensions,
rtc::ArrayView<const RtpHeaderExtensionCapability>)
-END_PROXY_MAP()
+END_PROXY_MAP(RtpTransceiver)
} // namespace webrtc
diff --git a/pc/sctp_data_channel.cc b/pc/sctp_data_channel.cc
index 76091c2..359cc79 100644
--- a/pc/sctp_data_channel.cc
+++ b/pc/sctp_data_channel.cc
@@ -65,7 +65,7 @@
PROXY_METHOD0(void, Close)
// TODO(bugs.webrtc.org/11547): Change to run on the network thread.
PROXY_METHOD1(bool, Send, const DataBuffer&)
-END_PROXY_MAP()
+END_PROXY_MAP(DataChannel)
} // namespace
diff --git a/pc/video_track_source_proxy.h b/pc/video_track_source_proxy.h
index 5a6def6..8914dd0 100644
--- a/pc/video_track_source_proxy.h
+++ b/pc/video_track_source_proxy.h
@@ -42,7 +42,7 @@
PROXY_SECONDARY_METHOD1(void,
RemoveEncodedSink,
rtc::VideoSinkInterface<RecordableEncodedFrame>*)
-END_PROXY_MAP()
+END_PROXY_MAP(VideoTrackSource)
} // namespace webrtc
diff --git a/rtc_base/string_utils.h b/rtc_base/string_utils.h
index 23c55cb..d844e5e 100644
--- a/rtc_base/string_utils.h
+++ b/rtc_base/string_utils.h
@@ -88,6 +88,43 @@
// TODO(jonasolsson): replace with absl::Hex when that becomes available.
std::string ToHex(const int i);
+// CompileTimeString comprises of a string-like object which can be used as a
+// regular const char* in compile time and supports concatenation. Useful for
+// concatenating constexpr strings in for example macro declarations.
+namespace rtc_base_string_utils_internal {
+template <int NPlus1>
+struct CompileTimeString {
+ char string[NPlus1] = {0};
+ constexpr CompileTimeString() = default;
+ template <int MPlus1>
+ explicit constexpr CompileTimeString(const char (&chars)[MPlus1]) {
+ char* chars_pointer = string;
+ for (auto c : chars)
+ *chars_pointer++ = c;
+ }
+ template <int MPlus1>
+ constexpr auto Concat(CompileTimeString<MPlus1> b) {
+ CompileTimeString<NPlus1 + MPlus1 - 1> result;
+ char* chars_pointer = result.string;
+ for (auto c : string)
+ *chars_pointer++ = c;
+ chars_pointer = result.string + NPlus1 - 1;
+ for (auto c : b.string)
+ *chars_pointer++ = c;
+ result.string[NPlus1 + MPlus1 - 2] = 0;
+ return result;
+ }
+ constexpr operator const char*() { return string; }
+};
+} // namespace rtc_base_string_utils_internal
+
+// Makes a constexpr CompileTimeString<X> without having to specify X
+// explicitly.
+template <int N>
+constexpr auto MakeCompileTimeString(const char (&a)[N]) {
+ return rtc_base_string_utils_internal::CompileTimeString<N>(a);
+}
+
} // namespace rtc
#endif // RTC_BASE_STRING_UTILS_H_
diff --git a/rtc_base/string_utils_unittest.cc b/rtc_base/string_utils_unittest.cc
index 2fa1f22..120f7e6 100644
--- a/rtc_base/string_utils_unittest.cc
+++ b/rtc_base/string_utils_unittest.cc
@@ -39,4 +39,29 @@
#endif // WEBRTC_WIN
+TEST(CompileTimeString, MakeActsLikeAString) {
+ EXPECT_STREQ(MakeCompileTimeString("abc123"), "abc123");
+}
+
+TEST(CompileTimeString, ConvertibleToStdString) {
+ EXPECT_EQ(std::string(MakeCompileTimeString("abab")), "abab");
+}
+
+namespace detail {
+constexpr bool StringEquals(const char* a, const char* b) {
+ while (*a && *a == *b)
+ a++, b++;
+ return *a == *b;
+}
+} // namespace detail
+
+static_assert(detail::StringEquals(MakeCompileTimeString("handellm"),
+ "handellm"),
+ "String should initialize.");
+
+static_assert(detail::StringEquals(MakeCompileTimeString("abc123").Concat(
+ MakeCompileTimeString("def456ghi")),
+ "abc123def456ghi"),
+ "Strings should concatenate.");
+
} // namespace rtc
