Redirect logs to logcat on android

src/log.cpp

@@ -36,6 +36,10 @@
 #include <iostream>
 #include <iomanip>
 
+#ifdef __ANDROID__
+#include <android/log.h>
+#endif
+
 static lg::log_domain log_setup("logsetup");
 #define ERR_LS LOG_STREAM(err,   log_setup)
 #define WRN_LS LOG_STREAM(warn,  log_setup)
@@ -51,6 +55,31 @@ public:
 	null_streambuf() {}
 };
 
+#ifdef __ANDROID__
+class android_log_buf : public std::streambuf
+{
+	std::string output;
+	void write() {
+		auto newline { output.find_first_of("\n") };
+		if(newline != std::string::npos) {
+			__android_log_write(ANDROID_LOG_INFO, "wesnoth", output.substr(0, newline).c_str());
+			output = output.substr(newline+1);
+		}
+	}
+	protected:
+	virtual std::streamsize xsputn(const char_type* s, std::streamsize n) override {
+		output.append(s, n);
+		write();
+		return n;
+	}
+	virtual int_type overflow(int_type ch) override {
+		output.push_back(ch);
+		write();
+		return 1;
+	}
+};
+#endif
+
 } // end anonymous namespace
 
 static std::ostream null_ostream(new null_streambuf);
@@ -64,6 +93,10 @@ static std::ostream *output_stream_ = nullptr;
 
 static std::ostream& output()
 {
+#ifdef __ANDROID__
+	static std::ostream android_ostream(new android_log_buf);
+	return android_ostream;
+#endif
 	if(output_stream_) {
 		return *output_stream_;
 	}