perf(android): hide native symbols and consolidate compile flags

Only JNI_OnLoad has to leave the library - JNIEXPORT keeps it exported and
fbjni registers all natives via RegisterNatives. Shrinks the stripped release
.so by 42% (5.3 MB over all four ABIs, 5535 -> 87 exported symbols).

The nested buildTypes block never scoped anything: -O1 -g and -O2 were appended
to every variant, so debug was compiled with -O2. It now uses -O1.

Author: pinpong

android/CMakeLists.txt

@@ -13,6 +13,16 @@ add_library(${PACKAGE_NAME} SHARED
         src/main/cpp/cpp-adapter.cpp
 )
 
+# Compile options, only JNI_OnLoad has to be exported, hide every other symbol
+target_compile_options(${PACKAGE_NAME} PRIVATE
+        -frtti
+        -fexceptions
+        -Wall
+        -fstack-protector-all
+        -fvisibility=hidden
+        $<$<CONFIG:Debug>:-O1>
+)
+
 # Add Nitrogen specs :)
 include(${CMAKE_SOURCE_DIR}/../nitrogen/generated/android/RNGoogleMapsPlus+autolinking.cmake)
 

android/build.gradle

@@ -48,18 +48,8 @@ android {
 
     externalNativeBuild {
       cmake {
-        cppFlags "-frtti -fexceptions -Wall -fstack-protector-all"
         arguments "-DANDROID_STL=c++_shared", "-DANDROID_SUPPORT_FLEXIBLE_PAGE_SIZES=ON"
         abiFilters (*reactNativeArchitectures())
-
-        buildTypes {
-          debug {
-            cppFlags "-O1 -g"
-          }
-          release {
-            cppFlags "-O2"
-          }
-        }
       }
     }
   }

android/proguard-rules.pro

@@ -1,14 +1,8 @@
--keep class com.google.android.gms.** { *; }
--keep interface com.google.android.gms.** { *; }
+-keep class com.google.android.gms.maps.** { *; }
+-keep interface com.google.android.gms.maps.** { *; }
 -dontwarn com.google.android.gms.**
 -dontnote com.google.android.gms.**
 
--keep class * implements android.os.Parcelable { *; }
-
--keepclassmembers class **$Companion {
-    public *;
-}
-
 -keep class com.google.maps.android.** { *; }
 -keep interface com.google.maps.android.** { *; }
 -dontwarn com.google.maps.android.**
@@ -18,12 +12,7 @@
     @androidx.annotation.Keep *;
 }
 
--keep class com.caverock.androidsvg.** { *; }
+-keep class com.caverock.androidsvg.SVG { *; }
 -dontwarn com.caverock.androidsvg.**
 
--keepclassmembers class com.caverock.androidsvg.** {
-    public *;
-    protected *;
-}
-
 -keep class com.rngooglemapsplus.** { *; }