Bug 1658232 - Use std::string for ProfilerBacktrace::mName - r=gregtatum

Instead of keeping a pointer to a null-terminated string, it's simpler to keep a proper `std::string`, and it helps to keep the length ready for streaming.

Differential Revision: https://phabricator.services.mozilla.com/D86511

mozglue/baseprofiler/core/ProfilerBacktrace.cpp

@@ -20,7 +20,7 @@ ProfilerBacktrace::ProfilerBacktrace(
     const char* aName, int aThreadId,
     UniquePtr<ProfileChunkedBuffer> aProfileChunkedBuffer,
     UniquePtr<ProfileBuffer> aProfileBuffer)
-    : mName(strdup(aName)),
+    : mName(aName),
       mThreadId(aThreadId),
       mProfileChunkedBuffer(std::move(aProfileChunkedBuffer)),
       mProfileBuffer(std::move(aProfileBuffer)) {
@@ -44,8 +44,8 @@ void ProfilerBacktrace::StreamJSON(SpliceableJSONWriter& aWriter,
   // ProfileBuffer::AddJITInfoForRange because mProfileBuffer does not contain
   // any JitReturnAddr entries. For synchronous samples, JIT frames get expanded
   // at sample time.
-  StreamSamplesAndMarkers(mName.get(), mThreadId, *mProfileBuffer, aWriter, "",
-                          "", aProcessStartTime,
+  StreamSamplesAndMarkers(mName.c_str(), mThreadId, *mProfileBuffer, aWriter,
+                          "", "", aProcessStartTime,
                           /* aRegisterTime */ TimeStamp(),
                           /* aUnregisterTime */ TimeStamp(),
                           /* aSinceTime */ 0, aUniqueStacks);

mozglue/baseprofiler/core/ProfilerBacktrace.h

@@ -9,6 +9,8 @@
 
 #include "mozilla/UniquePtrExtensions.h"
 
+#include <string>
+
 namespace mozilla {
 
 class ProfileChunkedBuffer;
@@ -44,7 +46,7 @@ class ProfilerBacktrace {
   friend struct ProfileBufferEntryWriter::Serializer<ProfilerBacktrace>;
   friend struct ProfileBufferEntryReader::Deserializer<ProfilerBacktrace>;
 
-  UniqueFreePtr<char> mName;
+  std::string mName;
   int mThreadId;
   // `ProfileChunkedBuffer` in which `mProfileBuffer` stores its data; must be
   // located before `mProfileBuffer` so that it's destroyed after.
@@ -68,9 +70,7 @@ struct ProfileBufferEntryWriter::Serializer<baseprofiler::ProfilerBacktrace> {
       // Empty backtrace buffer.
       return ULEB128Size<Length>(0);
     }
-    return bufferBytes +
-           SumBytes(aBacktrace.mThreadId,
-                    WrapProfileBufferUnownedCString(aBacktrace.mName.get()));
+    return bufferBytes + SumBytes(aBacktrace.mThreadId, aBacktrace.mName);
   }
 
   static void Write(ProfileBufferEntryWriter& aEW,
@@ -83,7 +83,7 @@ struct ProfileBufferEntryWriter::Serializer<baseprofiler::ProfilerBacktrace> {
     }
     aEW.WriteObject(aBacktrace.mProfileChunkedBuffer);
     aEW.WriteObject(aBacktrace.mThreadId);
-    aEW.WriteObject(WrapProfileBufferUnownedCString(aBacktrace.mName.get()));
+    aEW.WriteObject(aBacktrace.mName);
   }
 };
 

tools/profiler/core/ProfilerBacktrace.cpp

@@ -16,7 +16,7 @@ ProfilerBacktrace::ProfilerBacktrace(
     const char* aName, int aThreadId,
     mozilla::UniquePtr<mozilla::ProfileChunkedBuffer> aProfileChunkedBuffer,
     mozilla::UniquePtr<ProfileBuffer> aProfileBuffer)
-    : mName(strdup(aName)),
+    : mName(aName),
       mThreadId(aThreadId),
       mProfileChunkedBuffer(std::move(aProfileChunkedBuffer)),
       mProfileBuffer(std::move(aProfileBuffer)) {
@@ -41,7 +41,7 @@ void ProfilerBacktrace::StreamJSON(SpliceableJSONWriter& aWriter,
   // ProfileBuffer::AddJITInfoForRange because mProfileBuffer does not contain
   // any JitReturnAddr entries. For synchronous samples, JIT frames get expanded
   // at sample time.
-  StreamSamplesAndMarkers(mName.get(), mThreadId, *mProfileBuffer, aWriter,
+  StreamSamplesAndMarkers(mName.c_str(), mThreadId, *mProfileBuffer, aWriter,
                           ""_ns, ""_ns, aProcessStartTime,
                           /* aRegisterTime */ mozilla::TimeStamp(),
                           /* aUnregisterTime */ mozilla::TimeStamp(),

tools/profiler/core/ProfilerBacktrace.h

@@ -12,6 +12,8 @@
 #include "mozilla/ProfileBufferEntrySerialization.h"
 #include "mozilla/UniquePtrExtensions.h"
 
+#include <string>
+
 class ProfileBuffer;
 class ProfilerCodeAddressService;
 class ThreadInfo;
@@ -51,7 +53,7 @@ class ProfilerBacktrace {
   friend struct mozilla::ProfileBufferEntryReader::Deserializer<
       ProfilerBacktrace>;
 
-  mozilla::UniqueFreePtr<char> mName;
+  std::string mName;
   int mThreadId;
   // `ProfileChunkedBuffer` in which `mProfileBuffer` stores its data; must be
   // located before `mProfileBuffer` so that it's destroyed after.
@@ -73,9 +75,7 @@ struct mozilla::ProfileBufferEntryWriter::Serializer<ProfilerBacktrace> {
     if (bufferBytes == 0) {
       return ULEB128Size<Length>(0);
     }
-    return bufferBytes +
-           SumBytes(aBacktrace.mThreadId,
-                    WrapProfileBufferUnownedCString(aBacktrace.mName.get()));
+    return bufferBytes + SumBytes(aBacktrace.mThreadId, aBacktrace.mName);
   }
   static void Write(mozilla::ProfileBufferEntryWriter& aEW,
                     const ProfilerBacktrace& aBacktrace) {
@@ -86,7 +86,7 @@ struct mozilla::ProfileBufferEntryWriter::Serializer<ProfilerBacktrace> {
     }
     aEW.WriteObject(*aBacktrace.mProfileChunkedBuffer);
     aEW.WriteObject(aBacktrace.mThreadId);
-    aEW.WriteObject(WrapProfileBufferUnownedCString(aBacktrace.mName.get()));
+    aEW.WriteObject(aBacktrace.mName);
   }
 };