A first pass to correctly convert between c char strings to Java Strings.

src/main/cpp/generic.cpp

@@ -1,5 +1,5 @@
 /*
- * Generic functions
+ * Generic cross-platform functions.
  */
 #include "native.h"
 #include "generic.h"

src/main/cpp/linux.cpp

@@ -22,9 +22,9 @@ Java_net_rubygrapefruit_platform_internal_jni_PosixFileSystemFunctions_listFileS
     jmethodID method = env->GetMethodID(info_class, "add", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Z)V");
 
     while (getmntent_r(fp, &mount_info, buf, sizeof(buf)) != NULL) {
-        jstring mount_point = env->NewStringUTF(mount_info.mnt_dir);
-        jstring file_system_type = env->NewStringUTF(mount_info.mnt_type);
-        jstring device_name = env->NewStringUTF(mount_info.mnt_fsname);
+        jstring mount_point = char_to_java(env, mount_info.mnt_dir, result);
+        jstring file_system_type = char_to_java(env, mount_info.mnt_type, result);
+        jstring device_name = char_to_java(env, mount_info.mnt_fsname, result);
         env->CallVoidMethod(info, method, mount_point, file_system_type, device_name, JNI_FALSE);
     }
 

src/main/cpp/osx.cpp

@@ -30,9 +30,9 @@ Java_net_rubygrapefruit_platform_internal_jni_PosixFileSystemFunctions_listFileS
     jmethodID method = env->GetMethodID(info_class, "add", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Z)V");
 
     for (int i = 0; i < fs_count; i++) {
-        jstring mount_point = env->NewStringUTF(buf[i].f_mntonname);
-        jstring file_system_type = env->NewStringUTF(buf[i].f_fstypename);
-        jstring device_name = env->NewStringUTF(buf[i].f_mntfromname);
+        jstring mount_point = char_to_java(env, buf[i].f_mntonname, result);
+        jstring file_system_type = char_to_java(env, buf[i].f_fstypename, result);
+        jstring device_name = char_to_java(env, buf[i].f_mntfromname, result);
         jboolean remote = (buf[i].f_flags & MNT_LOCAL) == 0;
         env->CallVoidMethod(info, method, mount_point, file_system_type, device_name, remote);
     }

src/main/cpp/posix.cpp

@@ -14,6 +14,7 @@
 #include <sys/utsname.h>
 #include <xlocale.h>
 #include <locale.h>
+#include <string.h>
 
 /*
  * Marks the given result as failed, using the current value of errno
@@ -22,6 +23,24 @@ void mark_failed_with_errno(JNIEnv *env, const char* message, jobject result) {
     mark_failed_with_code(env, message, errno, result);
 }
 
+char_str* java_to_char_str(JNIEnv *env, jstring string, jobject result) {
+    return NULL;
+}
+
+void char_str_free(char_str* str) {
+}
+
+jstring char_to_java(JNIEnv* env, const char* chars, jobject result) {
+    size_t len = strlen(chars);
+    jbyteArray byteArray = env->NewByteArray(len);
+    jbyte* bytes = env->GetByteArrayElements(byteArray, NULL);
+    memcpy(bytes, chars, len);
+    env->ReleaseByteArrayElements(byteArray, bytes, JNI_COMMIT);
+    jclass strClass = env->FindClass("java/lang/String");
+    jmethodID method = env->GetMethodID(strClass, "<init>", "([B)V");
+    return (jstring)env->NewObject(strClass, method, byteArray);
+}
+
 JNIEXPORT void JNICALL
 Java_net_rubygrapefruit_platform_internal_jni_NativeLibraryFunctions_getSystemInfo(JNIEnv *env, jclass target, jobject info, jobject result) {
     jclass infoClass = env->GetObjectClass(info);
@@ -44,11 +63,11 @@ Java_net_rubygrapefruit_platform_internal_jni_NativeLibraryFunctions_getSystemIn
     }
 
     jfieldID osNameField = env->GetFieldID(infoClass, "osName", "Ljava/lang/String;");
-    env->SetObjectField(info, osNameField, env->NewStringUTF(machine_info.sysname));
+    env->SetObjectField(info, osNameField, char_to_java(env, machine_info.sysname, result));
     jfieldID osVersionField = env->GetFieldID(infoClass, "osVersion", "Ljava/lang/String;");
-    env->SetObjectField(info, osVersionField, env->NewStringUTF(machine_info.release));
+    env->SetObjectField(info, osVersionField, char_to_java(env, machine_info.release, result));
     jfieldID machineArchitectureField = env->GetFieldID(infoClass, "machineArchitecture", "Ljava/lang/String;");
-    env->SetObjectField(info, machineArchitectureField, env->NewStringUTF(machine_info.machine));
+    env->SetObjectField(info, machineArchitectureField, char_to_java(env, machine_info.machine, result));
 }
 
 /*
@@ -247,7 +266,7 @@ Java_net_rubygrapefruit_platform_internal_jni_TerminfoFunctions_initTerminal(JNI
 
         jclass destClass = env->GetObjectClass(capabilities);
         jfieldID field = env->GetFieldID(destClass, "terminalName", "Ljava/lang/String;");
-        jstring jtermType = env->NewStringUTF(termType);
+        jstring jtermType = char_to_java(env, termType, result);
         env->SetObjectField(capabilities, field, jtermType);
 
         // Text attributes

src/main/headers/generic.h

@@ -22,6 +22,63 @@ extern void mark_failed_with_errno(JNIEnv *env, const char* message, jobject res
  */
 extern void mark_failed_with_code(JNIEnv *env, const char* message, int error_code, jobject result);
 
+typedef struct wchar_struct {
+    // Not NULL terminated
+    wchar_t* chars;
+    // number of characters in the string
+    size_t len;
+    jstring source;
+    JNIEnv *env;
+} wchar_str;
+
+/*
+ * Converts the given Java string to a wchar_str. Should call wchar_str_free() when finished.
+ *
+ * Returns NULL on failure.
+ */
+extern wchar_str*
+java_to_wchar_str(JNIEnv *env, jstring string, jobject result);
+
+/*
+ * Releases resources used by the given string.
+ */
+extern void wchar_str_free(wchar_str* str);
+
+/*
+ * Converts the given wchar_t string to a Java string.
+ *
+ * Returns NULL on failure.
+ */
+extern jstring wchar_to_java(JNIEnv* env, const wchar_t* chars, size_t len, jobject result);
+
+typedef struct char_struct {
+    // NULL terminated
+    char* chars;
+    // Number of chars in the string, excluding the NULL terminator
+    size_t len;
+    jstring source;
+    JNIEnv *env;
+} char_str;
+
+/*
+ * Converts the given Java string to a char_str. Should call char_str_free() when finished.
+ *
+ * Returns NULL on failure.
+ */
+extern char_str* java_to_char_str(JNIEnv *env, jstring string, jobject result);
+
+/*
+ * Releases resources used by the given string.
+ */
+extern void char_str_free(char_str* str);
+
+/*
+ * Converts the given NULL terminated char string to a Java string.
+ *
+ * Returns NULL on failure.
+ */
+extern jstring char_to_java(JNIEnv* env, const char* chars, jobject result);
+
 #ifdef __cplusplus
 }
 #endif