Android: Add content provider support to File::IOFile

Taking the hit now to prepare us for when Google Play will
force us to use scoped storage...

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/utils/ContentHandler.java

@@ -0,0 +1,23 @@
+package org.dolphinemu.dolphinemu.utils;
+
+import android.net.Uri;
+
+import org.dolphinemu.dolphinemu.DolphinApplication;
+
+import java.io.FileNotFoundException;
+
+public class ContentHandler
+{
+  public static int openFd(String uri, String mode)
+  {
+    try
+    {
+      return DolphinApplication.getAppContext().getContentResolver()
+              .openFileDescriptor(Uri.parse(uri), mode).detachFd();
+    }
+    catch (FileNotFoundException | NullPointerException e)
+    {
+      return -1;
+    }
+  }
+}

Source/Android/jni/AndroidCommon/AndroidCommon.cpp

@@ -11,6 +11,7 @@
 #include <jni.h>
 
 #include "Common/StringUtil.h"
+#include "jni/AndroidCommon/IDCache.h"
 
 std::string GetJString(JNIEnv* env, jstring jstr)
 {
@@ -40,3 +41,20 @@ std::vector<std::string> JStringArrayToVector(JNIEnv* env, jobjectArray array)
 
   return result;
 }
+
+int OpenAndroidContent(const std::string& uri, const std::string& mode)
+{
+  JNIEnv* env = IDCache::GetEnvForThread();
+  const jint fd = env->CallStaticIntMethod(IDCache::GetContentHandlerClass(),
+                                           IDCache::GetContentHandlerOpenFd(), ToJString(env, uri),
+                                           ToJString(env, mode));
+
+  // We can get an IllegalArgumentException when passing an invalid mode
+  if (env->ExceptionCheck())
+  {
+    env->ExceptionDescribe();
+    abort();
+  }
+
+  return fd;
+}

Source/Android/jni/AndroidCommon/AndroidCommon.h

@@ -11,3 +11,5 @@
 std::string GetJString(JNIEnv* env, jstring jstr);
 jstring ToJString(JNIEnv* env, const std::string& str);
 std::vector<std::string> JStringArrayToVector(JNIEnv* env, jobjectArray array);
+
+int OpenAndroidContent(const std::string& uri, const std::string& mode);

Source/Android/jni/AndroidCommon/CMakeLists.txt

@@ -0,0 +1,15 @@
+add_library(androidcommon STATIC
+  AndroidCommon.cpp
+  AndroidCommon.h
+  IDCache.cpp
+  IDCache.h
+)
+
+target_link_libraries(androidcommon
+PRIVATE
+  android
+  log
+  "-Wl,--no-warn-mismatch"
+  "-Wl,--whole-archive"
+  "-Wl,--no-whole-archive"
+)

Source/Android/jni/AndroidCommon/IDCache.cpp

@@ -39,6 +39,9 @@ static jmethodID s_ini_file_section_constructor;
 static jclass s_compress_cb_class;
 static jmethodID s_compress_cb_run;
 
+static jclass s_content_handler_class;
+static jmethodID s_content_handler_open_fd;
+
 namespace IDCache
 {
 JNIEnv* GetEnvForThread()
@@ -174,6 +177,16 @@ jmethodID GetCompressCallbackRun()
   return s_compress_cb_run;
 }
 
+jclass GetContentHandlerClass()
+{
+  return s_content_handler_class;
+}
+
+jmethodID GetContentHandlerOpenFd()
+{
+  return s_content_handler_open_fd;
+}
+
 }  // namespace IDCache
 
 #ifdef __cplusplus
@@ -241,6 +254,12 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved)
   s_compress_cb_class = reinterpret_cast<jclass>(env->NewGlobalRef(compress_cb_class));
   s_compress_cb_run = env->GetMethodID(s_compress_cb_class, "run", "(Ljava/lang/String;F)Z");
 
+  const jclass content_handler_class =
+      env->FindClass("org/dolphinemu/dolphinemu/utils/ContentHandler");
+  s_content_handler_class = reinterpret_cast<jclass>(env->NewGlobalRef(content_handler_class));
+  s_content_handler_open_fd = env->GetStaticMethodID(s_content_handler_class, "openFd",
+                                                     "(Ljava/lang/String;Ljava/lang/String;)I");
+
   return JNI_VERSION;
 }
 
@@ -258,6 +277,7 @@ void JNI_OnUnload(JavaVM* vm, void* reserved)
   env->DeleteGlobalRef(s_ini_file_class);
   env->DeleteGlobalRef(s_ini_file_section_class);
   env->DeleteGlobalRef(s_compress_cb_class);
+  env->DeleteGlobalRef(s_content_handler_class);
 }
 
 #ifdef __cplusplus

Source/Android/jni/AndroidCommon/IDCache.h

@@ -41,4 +41,7 @@ jmethodID GetIniFileSectionConstructor();
 jclass GetCompressCallbackClass();
 jmethodID GetCompressCallbackRun();
 
+jclass GetContentHandlerClass();
+jmethodID GetContentHandlerOpenFd();
+
 }  // namespace IDCache

Source/Android/jni/CMakeLists.txt

@@ -1,7 +1,6 @@
 add_library(main SHARED
-  AndroidCommon/AndroidCommon.cpp
-  AndroidCommon/IDCache.cpp
   GameList/GameFile.cpp
+  GameList/GameFile.h
   GameList/GameFileCache.cpp
   IniFile.cpp
   MainAndroid.cpp
@@ -10,6 +9,7 @@ add_library(main SHARED
 
 target_link_libraries(main
 PRIVATE
+  androidcommon
   core
   uicommon
 )
@@ -32,3 +32,5 @@ file(REMOVE_RECURSE ${CMAKE_SOURCE_DIR}/Source/Android/app/src/main/assets/Sys/R
 file(REMOVE_RECURSE ${CMAKE_SOURCE_DIR}/Source/Android/app/src/main/assets/Sys/Themes/)
 
 set(CPACK_PACKAGE_EXECUTABLES ${CPACK_PACKAGE_EXECUTABLES} main)
+
+add_subdirectory(AndroidCommon)

Source/CMakeLists.txt

@@ -64,8 +64,8 @@ if (MSVC)
   add_definitions(/I${PCH_DIRECTORY})
   add_definitions(/Yu${PCH_PATH}) 
 
-	# Don't include timestamps in binaries
-	add_link_options(/Brepro)
+  # Don't include timestamps in binaries
+  add_link_options(/Brepro)
 endif()
 
 # These aren't actually needed for C11/C++11

Source/Core/Common/CMakeLists.txt

@@ -164,6 +164,11 @@ elseif(WIN32)
   if (_M_X86_64)
 	  target_link_libraries(common PRIVATE opengl32.lib)
   endif()
+elseif (ANDROID)
+  target_link_libraries(common
+  PRIVATE
+    androidcommon
+  )
 endif()
 
 if(ANDROID)

Source/Core/Common/File.cpp

@@ -15,6 +15,13 @@
 #include <unistd.h>
 #endif
 
+#ifdef ANDROID
+#include <algorithm>
+
+#include "Common/StringUtil.h"
+#include "jni/AndroidCommon/AndroidCommon.h"
+#endif
+
 #include "Common/CommonTypes.h"
 #include "Common/File.h"
 #include "Common/FileUtil.h"
@@ -62,7 +69,21 @@ bool IOFile::Open(const std::string& filename, const char openmode[])
 #ifdef _WIN32
   m_good = _tfopen_s(&m_file, UTF8ToTStr(filename).c_str(), UTF8ToTStr(openmode).c_str()) == 0;
 #else
-  m_file = std::fopen(filename.c_str(), openmode);
+#ifdef ANDROID
+  if (StringBeginsWith(filename, "content://"))
+  {
+    // The Java method which OpenAndroidContent passes the mode to does not support the b specifier.
+    // Since we're on POSIX, it's fine to just remove the b.
+    std::string mode_without_b(openmode);
+    mode_without_b.erase(std::remove(mode_without_b.begin(), mode_without_b.end(), 'b'),
+                         mode_without_b.end());
+    m_file = fdopen(OpenAndroidContent(filename, mode_without_b), mode_without_b.c_str());
+  }
+  else
+#endif
+  {
+    m_file = std::fopen(filename.c_str(), openmode);
+  }
   m_good = m_file != nullptr;
 #endif