FYI: FileChannelImpl fixlets

[Mark Wielaard]

Hi,

The following was reported a long time ago.
It is obviously the correct thing to do.

2004-07-04  Stephen Crawley <address@hidden>

       * native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c
       (Java_gnu_java_nio_channels_FileChannelImpl_read___3BII):
       Check zero length early.
       (Java_gnu_java_nio_channels_FileChannelImpl_write___3BII):
       Check zero length early. Return immediatly when exception is thrown.


We could also have checked the length in the java source, but since I
had this variant of the patch already tested and in my tree I didn't
want to change anything about it just before the release.

Cheers,

Mark

Index: native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c
===================================================================
RCS file: 
/cvsroot/classpath/classpath/native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c,v
retrieving revision 1.11
diff -u -r1.11 gnu_java_nio_channels_FileChannelImpl.c
--- native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c 21 Jun 2004 
17:15:10 -0000      1.11
+++ native/jni/java-nio/gnu_java_nio_channels_FileChannelImpl.c 4 Jul 2004 
20:54:51 -0000
@@ -539,6 +539,10 @@
 
   native_fd = get_native_fd(env, obj);
 
+  /* Must return 0 if an attempt is made to read 0 bytes. */
+  if (length == 0)
+    return 0;
+
   bufptr = (*env)->GetByteArrayElements(env, buffer, 0);
   if (!bufptr)
     {
@@ -546,10 +550,6 @@
       return(-1);
     }
 
-  /* Must return 0 if an attempt is made to read 0 bytes. */
-  if (length == 0)
-    return 0;
-
   bytes_read = 0;
   do
     {
@@ -621,10 +621,15 @@
 
   native_fd = get_native_fd(env, obj);
 
+  /* Just return if an attempt is made to write 0 bytes. */
+  if (length == 0)
+    return;
+
   bufptr = (*env)->GetByteArrayElements(env, buffer, 0);
   if (!bufptr)
     {
       JCL_ThrowException(env, IO_EXCEPTION, "Unexpected JNI error");
+      return;
     }
 
   bytes_written = 0;
@@ -637,6 +642,7 @@
           JCL_ThrowException(env, IO_EXCEPTION,
                              TARGET_NATIVE_LAST_ERROR_STRING());
           (*env)->ReleaseByteArrayElements(env, buffer, bufptr, 0);
+          return;
        }
       bytes_written += n;
     }

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