First pass at nqp::getcfh on JVM.

Author: jnthn

src/vm/jvm/QAST/Compiler.nqp

@@ -1898,6 +1898,7 @@ QAST::OperationsJAST.map_classlib_core_op('sayfh', $TYPE_OPS, 'sayfh', [$RT_OBJ,
 QAST::OperationsJAST.map_classlib_core_op('readlinefh', $TYPE_OPS, 'readlinefh', [$RT_OBJ], $RT_STR, :tc);
 QAST::OperationsJAST.map_classlib_core_op('readlineintfh', $TYPE_OPS, 'readlineintfh', [$RT_OBJ, $RT_STR], $RT_STR, :tc);
 QAST::OperationsJAST.map_classlib_core_op('readallfh', $TYPE_OPS, 'readallfh', [$RT_OBJ], $RT_STR, :tc);
+QAST::OperationsJAST.map_classlib_core_op('getcfh', $TYPE_OPS, 'getcfh', [$RT_OBJ], $RT_STR, :tc);
 QAST::OperationsJAST.map_classlib_core_op('eoffh', $TYPE_OPS, 'eoffh', [$RT_OBJ], $RT_INT, :tc);
 QAST::OperationsJAST.map_classlib_core_op('closefh', $TYPE_OPS, 'closefh', [$RT_OBJ], $RT_OBJ, :tc);
 

src/vm/jvm/runtime/org/perl6/nqp/io/IIOSyncReadable.java

@@ -6,5 +6,6 @@ public interface IIOSyncReadable {
     public String slurp(ThreadContext tc);
     public String readline(ThreadContext tc);
     public byte[] read(ThreadContext tc, int bytes);
+    public String getc(ThreadContext tc);
     public boolean eof(ThreadContext tc);
 }

src/vm/jvm/runtime/org/perl6/nqp/io/StandardReadHandle.java

@@ -83,6 +83,23 @@ public synchronized String readline(ThreadContext tc) {
         }
     }
 
+    public synchronized String getc(ThreadContext tc) {
+        try {
+            if (br == null)
+                br = new BufferedReader(new InputStreamReader(is, cs));
+            int read = br.read();
+            if (read == -1) {
+                eof = true;
+                return "";
+            }
+            else {
+                return String.valueOf(read);
+            }
+        } catch (IOException e) {
+            throw ExceptionHandling.dieInternal(tc, e);
+        }
+    }
+    
     public synchronized String readlineInteractive(ThreadContext tc, String prompt) {
         try {
             if (cr == null)

src/vm/jvm/runtime/org/perl6/nqp/io/SyncHandle.java

@@ -7,6 +7,8 @@
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.nio.charset.CharsetEncoder;
+import java.nio.charset.CoderResult;
+import java.nio.charset.MalformedInputException;
 import java.util.ArrayList;
 
 import org.perl6.nqp.runtime.ExceptionHandling;
@@ -133,6 +135,53 @@ private String decodeBuffers(ArrayList<ByteBuffer> buffers, int total) throws IO
         return dec.decode(allBytes).toString();
     }
 
+    public synchronized String getc(ThreadContext tc) {
+        try {
+            int maxBytes = (int)enc.maxBytesPerChar();
+            ByteBuffer toDecode = ByteBuffer.allocate(maxBytes);
+            CharBuffer decoded = CharBuffer.allocate(1);
+            for (int i = 0; i < maxBytes; i++) {
+                /* Ensure we have a read buffer available. */
+                if (readBuffer == null) {
+                    readBuffer = ByteBuffer.allocate(32768);
+                    if (chan.read(readBuffer) == -1) {
+                        /* End of file. */
+                        eof = true;
+                        if (i == 0) {
+                            /* Fine, just no char. */
+                            return "";
+                        }
+                        else {
+                            /* Malformed; following will likely throw. */
+                            toDecode.position(0);
+                            dec.decode(toDecode, decoded, true).throwException();
+                            return decoded.toString();
+                        }    
+                    }
+                    readBuffer.flip();
+                }
+                
+                /* Get a character from the read buffer. */
+                toDecode.position(i);
+                toDecode.put(readBuffer.get());
+                if (readBuffer.remaining() == 0)
+                    readBuffer = null;
+
+                /* Try to decode; if we fail, try another byte. */
+                toDecode.position(0);
+                CoderResult cr = dec.decode(toDecode, decoded, false);
+                if (!cr.isError()) {
+                    decoded.rewind();
+                    return decoded.toString();
+                }
+            }
+            throw new MalformedInputException(maxBytes);
+        }
+        catch (IOException e) {
+            throw ExceptionHandling.dieInternal(tc, e);
+        }
+    }
+    
     public boolean eof(ThreadContext tc) {
         return eof;
     }

src/vm/jvm/runtime/org/perl6/nqp/runtime/Ops.java

@@ -611,6 +611,21 @@ public static String readallfh(SixModelObject obj, ThreadContext tc) {
         }
     }
 
+    public static String getcfh(SixModelObject obj, ThreadContext tc) {
+        if (obj instanceof IOHandleInstance) {
+            IOHandleInstance h = (IOHandleInstance)obj;
+            if (h.handle instanceof IIOSyncReadable)
+                return ((IIOSyncReadable)h.handle).getc(tc);
+            else
+                throw ExceptionHandling.dieInternal(tc,
+                    "This handle does not support getc");
+        }
+        else {
+            throw ExceptionHandling.dieInternal(tc,
+                "getcfh requires an object with the IOHandle REPR");
+        }
+    }
+    
     public static long eoffh(SixModelObject obj, ThreadContext tc) {
         if (obj instanceof IOHandleInstance) {
             IOHandleInstance h = (IOHandleInstance)obj;