Enable stdout/stderr logging to logcat on android

monero_libwallet2_api_c/CMakeLists.txt

@@ -32,6 +32,7 @@ if(${HOST_ABI} STREQUAL "x86_64-linux-android" OR
    ${HOST_ABI} STREQUAL "aarch64-linux-android" OR
    ${HOST_ABI} STREQUAL "armv7a-linux-androideabi")
     add_link_options(-stdlib=libc++ -static-libstdc++)
+    set(EXTRA_LIBS_ANDROID log)
 endif()
 
 add_library( wallet2_api_c

monero_libwallet2_api_c/src/main/cpp/helpers.cpp

@@ -9,6 +9,71 @@
 #include <set>
 #include <sstream>
 #include <cstring>
+#include <thread>
+
+#ifdef __ANDROID__
+#include <android/log.h>
+
+#define LOG_TAG "moneroc"
+#define BUFFER_SIZE 1024*32
+
+static int stdoutToLogcat(const char *buf, int size) {
+    __android_log_write(ANDROID_LOG_INFO, LOG_TAG, buf);
+    return size;
+}
+
+static int stderrToLogcat(const char *buf, int size) {
+    __android_log_write(ANDROID_LOG_ERROR, LOG_TAG, buf);
+    return size;
+}
+
+void redirectStdoutThread(int pipe_stdout[2]) {
+    char bufferStdout[BUFFER_SIZE];
+    while (true) {
+        int read_size = read(pipe_stdout[0], bufferStdout, sizeof(bufferStdout) - 1);
+        if (read_size > 0) {
+            bufferStdout[read_size] = '\0';
+            stdoutToLogcat(bufferStdout, read_size);
+        }
+    }
+}
+
+void redirectStderrThread(int pipe_stderr[2]) {
+    char bufferStderr[BUFFER_SIZE];
+    while (true) {
+        int read_size = read(pipe_stderr[0], bufferStderr, sizeof(bufferStderr) - 1);
+        if (read_size > 0) {
+            bufferStderr[read_size] = '\0';
+            stderrToLogcat(bufferStderr, read_size);
+        }
+    }
+}
+
+void setupAndroidLogging() {
+    static int pfdStdout[2];
+    static int pfdStderr[2];
+
+    pipe(pfdStdout);
+    pipe(pfdStderr);
+
+    dup2(pfdStdout[1], STDOUT_FILENO);
+    dup2(pfdStderr[1], STDERR_FILENO);
+
+    std::thread stdoutThread(redirectStdoutThread, pfdStdout);
+    std::thread stderrThread(redirectStderrThread, pfdStderr);
+
+    stdoutThread.detach();
+    stderrThread.detach();
+}
+
+#endif // __ANDROID__
+
+__attribute__((constructor))
+void library_init() {
+#ifdef __ANDROID__
+    setupAndroidLogging();  // This will now run automatically when the library is loaded
+#endif
+}
 
 const char* vectorToString(const std::vector<std::string>& vec, const std::string separator) {
     // Check if the vector is empty
@@ -195,4 +260,4 @@ std::vector<uint64_t> splitStringUint(const std::string& str, const std::string&
     }
     tokens.push_back(std::stoull(content));  // Inserting the last token
     return tokens;
-}
+}