Call logger from within YGConfig

Summary:
@public

Stricter encapsulation of logging callbacks within `YGConfig`.

Instead of invoking the logging callback directly (`node->logger(...)`), callers now have to go through `YGConfig::log()`.

This change will allow us to add the concept of a *Layout Context,* where logging functions will be able to receive an additional `void *` argument if configured accordingly. This API will be used internally for Yoga’s JNI bindings, to avoid storing a weak JNI reference for each node, and avoid reference table overflows.

Changed API:

- `YGConfig::logger()` -> `YGConfig::log()`

Reviewed By: SidharthGuglani

Differential Revision: D14123483

fbshipit-source-id: 87b8bb7de0e4346b6a41e57a70ac4eb8d79b24af

yoga/YGConfig.cpp

@@ -6,4 +6,13 @@
  */
 #include "YGConfig.h"
 
-YGConfig::YGConfig(YGLogger logger) : logger(logger) {}
+YGConfig::YGConfig(YGLogger logger) : logger_{logger} {}
+
+void YGConfig::log(
+    YGConfig* config,
+    YGNode* node,
+    YGLogLevel logLevel,
+    const char* format,
+    va_list args) {
+  logger_(config, node, logLevel, format, args);
+}

yoga/YGConfig.h

@@ -10,17 +10,24 @@
 #include "Yoga.h"
 
 struct YGConfig {
-  std::array<bool, facebook::yoga::enums::count<YGExperimentalFeature>()>
-      experimentalFeatures = {};
+private:
+  YGLogger logger_;
+
+public:
   bool useWebDefaults = false;
   bool useLegacyStretchBehaviour = false;
   bool shouldDiffLayoutWithoutLegacyStretchBehaviour = false;
   bool printTree = false;
   float pointScaleFactor = 1.0f;
-  YGLogger logger;
   YGCloneNodeFunc cloneNodeCallback = nullptr;
+  std::array<bool, facebook::yoga::enums::count<YGExperimentalFeature>()>
+      experimentalFeatures = {};
   void* context = nullptr;
   YGMarkerCallbacks markerCallbacks = {nullptr, nullptr};
 
   YGConfig(YGLogger logger);
+  void log(YGConfig*, YGNode*, YGLogLevel, const char*, va_list);
+  void setLogger(YGLogger logger) {
+    logger_ = logger;
+  }
 };

yoga/Yoga.cpp

@@ -4182,12 +4182,12 @@ void YGNodeCalculateLayout(
 
 void YGConfigSetLogger(const YGConfigRef config, YGLogger logger) {
   if (logger != nullptr) {
-    config->logger = logger;
+    config->setLogger(logger);
   } else {
 #ifdef ANDROID
-    config->logger = &YGAndroidLog;
+    config->setLogger(&YGAndroidLog);
 #else
-    config->logger = &YGDefaultLog;
+    config->setLogger(&YGDefaultLog);
 #endif
   }
 }

yoga/log.cpp

@@ -24,7 +24,7 @@ void vlog(
     const char* format,
     va_list args) {
   YGConfig* logConfig = config != nullptr ? config : YGConfigGetDefault();
-  logConfig->logger(logConfig, node, level, format, args);
+  logConfig->log(logConfig, node, level, format, args);
 
   if (level == YGLogLevelFatal) {
     abort();