Include errno name in error messages, if the errno is known.

src/main/cpp/generic.cpp

@@ -21,14 +21,15 @@
 #include "generic.h"
 
 void mark_failed_with_message(JNIEnv *env, const char* message, jobject result) {
-    mark_failed_with_code(env, message, 0, result);
+    mark_failed_with_code(env, message, 0, NULL, result);
 }
 
-void mark_failed_with_code(JNIEnv *env, const char* message, int error_code, jobject result) {
+void mark_failed_with_code(JNIEnv *env, const char* message, int error_code, const char* error_code_message, jobject result) {
     jclass destClass = env->GetObjectClass(result);
-    jmethodID method = env->GetMethodID(destClass, "failed", "(Ljava/lang/String;I)V");
+    jmethodID method = env->GetMethodID(destClass, "failed", "(Ljava/lang/String;ILjava/lang/String;)V");
     jstring message_str = env->NewStringUTF(message);
-    env->CallVoidMethod(result, method, message_str, error_code);
+    jstring error_code_str = error_code_message == NULL ? NULL : env->NewStringUTF(error_code_message);
+    env->CallVoidMethod(result, method, message_str, error_code, error_code_str);
 }
 
 JNIEXPORT jint JNICALL

src/main/cpp/generic_posix.cpp

@@ -29,7 +29,14 @@
 #include <string.h>
 
 void mark_failed_with_errno(JNIEnv *env, const char* message, jobject result) {
-    mark_failed_with_code(env, message, errno, result);
+    const char * errno_message = NULL;
+    switch(errno) {
+        case ENOENT:
+            errno_message = "ENOENT";
+            break;
+    }
+
+    mark_failed_with_code(env, message, errno, errno_message, result);
 }
 
 char* java_to_char(JNIEnv *env, jstring string, jobject result) {

src/main/cpp/win.cpp

@@ -25,7 +25,7 @@
  * Marks the given result as failed, using the current value of GetLastError()
  */
 void mark_failed_with_errno(JNIEnv *env, const char* message, jobject result) {
-    mark_failed_with_code(env, message, GetLastError(), result);
+    mark_failed_with_code(env, message, GetLastError(), NULL, result);
 }
 
 jstring wchar_to_java(JNIEnv* env, const wchar_t* chars, size_t len, jobject result) {

src/main/headers/generic.h

@@ -23,7 +23,7 @@
 extern "C" {
 #endif
 
-#define NATIVE_VERSION 13
+#define NATIVE_VERSION 14
 
 /*
  * Marks the given result as failed, using the given error message
@@ -38,7 +38,7 @@ extern void mark_failed_with_errno(JNIEnv *env, const char* message, jobject res
 /*
  * Marks the given result as failed, using the given error message and error code
  */
-extern void mark_failed_with_code(JNIEnv *env, const char* message, int error_code, jobject result);
+extern void mark_failed_with_code(JNIEnv *env, const char* message, int error_code, const char* error_code_message, jobject result);
 
 /*
  * Converts the given Java string to a NULL terminated wchar_str. Should call free() when finished.

src/main/java/net/rubygrapefruit/platform/internal/FunctionResult.java

@@ -19,10 +19,12 @@ package net.rubygrapefruit.platform.internal;
 public class FunctionResult {
     String message;
     int errno;
+    private String errorCodeDescription;
 
-    void failed(String message, int errno) {
+    void failed(String message, int errno, String errorCodeDescription) {
         this.message = message;
         this.errno = errno;
+        this.errorCodeDescription = errorCodeDescription;
     }
 
     void failed(String message) {
@@ -34,6 +36,9 @@ public class FunctionResult {
     }
 
     public String getMessage() {
+        if (errorCodeDescription != null) {
+            return String.format("%s (%s errno %d)", message, errorCodeDescription, errno);
+        }
         if (errno != 0) {
             return String.format("%s (errno %d)", message, errno);
         }

src/main/java/net/rubygrapefruit/platform/internal/jni/NativeLibraryFunctions.java

@@ -20,7 +20,7 @@ import net.rubygrapefruit.platform.internal.FunctionResult;
 import net.rubygrapefruit.platform.internal.MutableSystemInfo;
 
 public class NativeLibraryFunctions {
-    public static final int VERSION = 13;
+    public static final int VERSION = 14;
 
     public static native int getVersion();
 

src/test/groovy/net/rubygrapefruit/platform/PosixFileTest.groovy

@@ -53,7 +53,7 @@ class PosixFileTest extends Specification {
 
         then:
         NativeException e = thrown()
-        e.message == "Could not set UNIX mode on $testFile: could not chmod file (errno 2)"
+        e.message == "Could not set UNIX mode on $testFile: could not chmod file (ENOENT errno 2)"
     }
 
     def "cannot get mode on file that does not exist"() {
@@ -64,7 +64,7 @@ class PosixFileTest extends Specification {
 
         then:
         NativeException e = thrown()
-        e.message == "Could not get UNIX mode on $testFile: could not stat file (errno 2)"
+        e.message == "Could not get UNIX mode on $testFile: could not stat file (ENOENT errno 2)"
     }
 
     def "can create symbolic link"() {
@@ -99,7 +99,7 @@ class PosixFileTest extends Specification {
 
         then:
         NativeException e = thrown()
-        e.message == "Could not read symlink $symlinkFile: could not lstat file (errno 2)"
+        e.message == "Could not read symlink $symlinkFile: could not lstat file (ENOENT errno 2)"
     }
 
     def "cannot read a symlink that is not a symlink"() {