IO: use JDK convenience methods

The benefit is that certain InputStreams can override the default
implementation for performance reasons.

Change-Id: I4c924157ec0f0ec63b0eca7cdbdc9325af24cab6

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/IO.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/IO.java
index 80877bbdc67690534882c656ac8d348d4cb0046e..8cc53162712bd8a2c72ebb7f9930dfb6f0dadb8b 100644 (file)
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/IO.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/IO.java
@@ -66,19 +66,7 @@ public class IO {
        public static final byte[] readSome(File path, int limit)
                        throws FileNotFoundException, IOException {
                try (SilentFileInputStream in = new SilentFileInputStream(path)) {
-                       byte[] buf = new byte[limit];
-                       int cnt = 0;
-                       for (;;) {
-                               int n = in.read(buf, cnt, buf.length - cnt);
-                               if (n <= 0)
-                                       break;
-                               cnt += n;
-                       }
-                       if (cnt == buf.length)
-                               return buf;
-                       byte[] res = new byte[cnt];
-                       System.arraycopy(buf, 0, res, 0, cnt);
-                       return res;
+                       return in.readNBytes(limit);
                }
        }
 
@@ -99,37 +87,10 @@ public class IO {
        public static final byte[] readFully(File path, int max)
                        throws FileNotFoundException, IOException {
                try (SilentFileInputStream in = new SilentFileInputStream(path)) {
-                       long sz = Math.max(path.length(), 1);
-                       if (sz > max)
+                       byte[] buf = in.readNBytes(max);
+                       if (in.read() != -1) {
                                throw new IOException(MessageFormat.format(
                                                JGitText.get().fileIsTooLarge, path));
-
-                       byte[] buf = new byte[(int) sz];
-                       int valid = 0;
-                       for (;;) {
-                               if (buf.length == valid) {
-                                       if (buf.length == max) {
-                                               int next = in.read();
-                                               if (next < 0)
-                                                       break;
-
-                                               throw new IOException(MessageFormat.format(
-                                                               JGitText.get().fileIsTooLarge, path));
-                                       }
-
-                                       byte[] nb = new byte[Math.min(buf.length * 2, max)];
-                                       System.arraycopy(buf, 0, nb, 0, valid);
-                                       buf = nb;
-                               }
-                               int n = in.read(buf, valid, buf.length - valid);
-                               if (n < 0)
-                                       break;
-                               valid += n;
-                       }
-                       if (valid < buf.length) {
-                               byte[] nb = new byte[valid];
-                               System.arraycopy(buf, 0, nb, 0, valid);
-                               buf = nb;
                        }
                        return buf;
                }
@@ -157,26 +118,7 @@ public class IO {
         */
        public static ByteBuffer readWholeStream(InputStream in, int sizeHint)
                        throws IOException {
-               byte[] out = new byte[sizeHint];
-               int pos = 0;
-               while (pos < out.length) {
-                       int read = in.read(out, pos, out.length - pos);
-                       if (read < 0)
-                               return ByteBuffer.wrap(out, 0, pos);
-                       pos += read;
-               }
-
-               int last = in.read();
-               if (last < 0)
-                       return ByteBuffer.wrap(out, 0, pos);
-
-               try (TemporaryBuffer.Heap tmp = new TemporaryBuffer.Heap(
-                               Integer.MAX_VALUE)) {
-                       tmp.write(out);
-                       tmp.write(last);
-                       tmp.copy(in);
-                       return ByteBuffer.wrap(tmp.toByteArray());
-               }
+               return ByteBuffer.wrap(in.readAllBytes());
        }
 
        /**
@@ -197,13 +139,9 @@ public class IO {
         */
        public static void readFully(final InputStream fd, final byte[] dst,
                        int off, int len) throws IOException {
-               while (len > 0) {
-                       final int r = fd.read(dst, off, len);
-                       if (r <= 0)
-                               throw new EOFException(JGitText.get().shortReadOfBlock);
-                       off += r;
-                       len -= r;
-               }
+               int read = fd.readNBytes(dst, off, len);
+               if (read != len)
+                       throw new EOFException(JGitText.get().shortReadOfBlock);
        }
 
        /**
@@ -271,14 +209,7 @@ public class IO {
         */
        public static int readFully(InputStream fd, byte[] dst, int off)
                        throws IOException {
-               int r;
-               int len = 0;
-               while (off < dst.length
-                               && (r = fd.read(dst, off, dst.length - off)) >= 0) {
-                       off += r;
-                       len += r;
-               }
-               return len;
+               return fd.readNBytes(dst, off, dst.length - off);
        }
 
        /**
@@ -300,6 +231,7 @@ public class IO {
         */
        public static void skipFully(InputStream fd, long toSkip)
                        throws IOException {
+               // same as fd.skipNBytes(toSkip) of JDK 12;
                while (toSkip > 0) {
                        final long r = fd.skip(toSkip);
                        if (r <= 0)