Re: [cp-patches] RFC: NIO, Non-blocking & Scatter/Gather (Again)

[Casey Marshall]

On Mar 27, 2006, at 5:42 AM, Michael Barker wrote:

Hi,

Another punt at the Non-blocking IO and Scatter/Gather stuff.  This
patch also adds scatter/gather support to the FileChannelImpl.

ChangeLog:

2006-03-19  Michael Barker <[EMAIL PROTECTED]>
        
        * vm/reference/gnu/java/nio/VMChannel.java: Added, supports setting
        non-blocking and scatter-gather io operations.
        * gnu/java/nio/PipeImpl.java: Retrofitted to use VMChannel
        * gnu/java/nio/SelectorImpl.java
        (register) Added condition for
gnu.java.nio.SocketChannelSelectionKeyImpl
        * gnu/java/nio/SocketChannelSelectionKeyImpl.java Added.
        * gnu/java/nio/channels/FileChannelImpl.java: Retrofitted to use
VMChannel
        * java/nio/FileChannel.java
        (read (ByteBuffer)) Changed to call abstract method.
        (write (ByteBuffer)) Changed to call abstract method.
        * include/gnu_java_nio_VMChannel.h: Added.
        * native/jni/java-nio/gnu_java_nio_VMChannel.c: Added.

Hi Michael.





Thanks,


--- native/jni/java-nio/gnu_java_nio_VMChannel.c        2006-05-05 
23:15:51.000000000 -0700
+++ native/jni/java-nio/gnu_java_nio_VMChannel.c.mine   2006-04-18 
14:52:45.000000000 -0700
@@ -66,6 +66,24 @@
 {
 #endif
 
+enum JCL_buffer_type { DIRECT, ARRAY, UNKNOWN };
+
+struct JCL_buffer
+{
+  enum JCL_buffer_type type;
+  jbyte *ptr;
+  jint offset;
+  jint position;
+  jint limit;
+  jint count;
+};
+
+jmethodID get_method_id(JNIEnv *, jclass, const char *, const char *);
+void JCL_print_buffer(JNIEnv *, struct JCL_buffer *);
+int JCL_init_buffer(JNIEnv *, struct JCL_buffer *, jobject);
+void JCL_release_buffer(JNIEnv *, struct JCL_buffer *, jobject, jint);
+void JCL_cleanup_buffers(JNIEnv *, struct JCL_buffer *, jint, jobjectArray, 
jint, jlong);
+
 static jfieldID address_fid;
 static jmethodID get_position_mid;
 static jmethodID set_position_mid;
@@ -89,20 +107,8 @@
   return mid;
 }
 
-enum JCL_buffer_type { DIRECT, ARRAY, UNKNOWN };
-
-struct JCL_buffer
-{
-  enum JCL_buffer_type type;
-  jbyte *ptr;
-  jint offset;
-  jint position;
-  jint limit;
-  jint count;
-};
-
 void
-JCL_print_buffer(JNIEnv *env, struct JCL_buffer *buf)
+JCL_print_buffer(JNIEnv *env __attribute__((__unused__)), struct JCL_buffer 
*buf)
 {
   fprintf(stdout, "Buffer - type: %d, ptr: %d\n", buf->type, (int)buf->ptr);
   fflush(stdout);
@@ -378,8 +384,8 @@
        jint length)
 {
   jint i;
-  jboolean is_error = JNI_FALSE;
-  char *error_msg;
+/*   jboolean is_error = JNI_FALSE; */
+/*   char *error_msg; */
   struct iovec buffers[JCL_IOV_MAX];
   struct JCL_buffer bi_list[JCL_IOV_MAX];
   ssize_t result;
@@ -454,8 +460,8 @@
        jint length)
 {
   int i;
-  jboolean is_error = JNI_FALSE;
-  char *error_msg;
+/*   jboolean is_error = JNI_FALSE; */
+/*   char *error_msg; */
   struct iovec buffers[JCL_IOV_MAX];
   struct JCL_buffer bi_list[JCL_IOV_MAX];
   ssize_t result;

I (finally!) took a look at this patch, and it looks fine to me; any bugs with it are worth the risk to have a real implementation of scatter/gather IO, in my opinion. One nit is that gnu_java_nio_VMChannel.c doesn't compile with -Werror for me (Darwin/x86, gcc 4.0.1), due to some unused variables and missing prototypes. I'll attach a patch that fixes these warnings.

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