Remove findbugs reported problems

src/main/java/org/xerial/snappy/Snappy.java

@@ -476,7 +476,7 @@ public class Snappy
             throws IOException
     {
         byte[] result = new byte[Snappy.uncompressedLength(input)];
-        int byteSize = Snappy.uncompress(input, 0, input.length, result, 0);
+        Snappy.uncompress(input, 0, input.length, result, 0);
         return result;
     }
 
@@ -569,7 +569,7 @@ public class Snappy
     {
         int uncompressedLength = Snappy.uncompressedLength(input, offset, length);
         char[] result = new char[uncompressedLength / 2];
-        int byteSize = impl.rawUncompress(input, offset, length, result, 0);
+        impl.rawUncompress(input, offset, length, result, 0);
         return result;
     }
 
@@ -585,7 +585,7 @@ public class Snappy
     {
         int uncompressedLength = Snappy.uncompressedLength(input, 0, input.length);
         double[] result = new double[uncompressedLength / 8];
-        int byteSize = impl.rawUncompress(input, 0, input.length, result, 0);
+        impl.rawUncompress(input, 0, input.length, result, 0);
         return result;
     }
 
@@ -687,7 +687,7 @@ public class Snappy
     {
         int uncompressedLength = Snappy.uncompressedLength(input, offset, length);
         float[] result = new float[uncompressedLength / 4];
-        int byteSize = impl.rawUncompress(input, offset, length, result, 0);
+        impl.rawUncompress(input, offset, length, result, 0);
         return result;
     }
 
@@ -718,7 +718,7 @@ public class Snappy
     {
         int uncompressedLength = Snappy.uncompressedLength(input, offset, length);
         int[] result = new int[uncompressedLength / 4];
-        int byteSize = impl.rawUncompress(input, offset, length, result, 0);
+        impl.rawUncompress(input, offset, length, result, 0);
         return result;
     }
 
@@ -749,7 +749,7 @@ public class Snappy
     {
         int uncompressedLength = Snappy.uncompressedLength(input, offset, length);
         long[] result = new long[uncompressedLength / 8];
-        int byteSize = impl.rawUncompress(input, offset, length, result, 0);
+        impl.rawUncompress(input, offset, length, result, 0);
         return result;
     }
 
@@ -780,7 +780,7 @@ public class Snappy
     {
         int uncompressedLength = Snappy.uncompressedLength(input, offset, length);
         short[] result = new short[uncompressedLength / 2];
-        int byteSize = impl.rawUncompress(input, offset, length, result, 0);
+        impl.rawUncompress(input, offset, length, result, 0);
         return result;
     }
 
@@ -838,7 +838,7 @@ public class Snappy
             UnsupportedEncodingException
     {
         byte[] uncompressed = new byte[uncompressedLength(input, offset, length)];
-        int compressedSize = uncompress(input, offset, length, uncompressed, 0);
+        uncompress(input, offset, length, uncompressed, 0);
         return new String(uncompressed, encoding);
     }
 
@@ -858,7 +858,7 @@ public class Snappy
             UnsupportedEncodingException
     {
         byte[] uncompressed = new byte[uncompressedLength(input, offset, length)];
-        int compressedSize = uncompress(input, offset, length, uncompressed, 0);
+        uncompress(input, offset, length, uncompressed, 0);
         return new String(uncompressed, encoding);
     }
 

src/main/java/org/xerial/snappy/SnappyCodec.java

@@ -48,7 +48,7 @@ import java.util.Arrays;
  */
 public class SnappyCodec
 {
-    public static final byte[] MAGIC_HEADER = new byte[] {-126, 'S', 'N', 'A', 'P', 'P', 'Y', 0};
+    static final byte[] MAGIC_HEADER = new byte[] {-126, 'S', 'N', 'A', 'P', 'P', 'Y', 0};
     public static final int MAGIC_LEN = MAGIC_HEADER.length;
     public static final int HEADER_SIZE = MAGIC_LEN + 8;
     public static final int MAGIC_HEADER_HEAD = SnappyOutputStream.readInt(MAGIC_HEADER, 0);
@@ -59,6 +59,7 @@ public class SnappyCodec
 
     public static final int DEFAULT_VERSION = 1;
     public static final int MINIMUM_COMPATIBLE_VERSION = 1;
+    public static final SnappyCodec currentHeader = new SnappyCodec(MAGIC_HEADER, DEFAULT_VERSION, MINIMUM_COMPATIBLE_VERSION);
 
     public final byte[] magic;
     public final int version;
@@ -85,6 +86,11 @@ public class SnappyCodec
         headerArray = header.toByteArray();
     }
 
+    public static byte[] getMagicHeader()
+    {
+        return MAGIC_HEADER.clone();
+    }
+
     @Override
     public String toString()
     {
@@ -124,7 +130,5 @@ public class SnappyCodec
         int compatibleVersion = d.readInt();
         return new SnappyCodec(magic, version, compatibleVersion);
     }
-
-    public static SnappyCodec currentHeader = new SnappyCodec(MAGIC_HEADER, DEFAULT_VERSION, MINIMUM_COMPATIBLE_VERSION);
 }
 

src/main/java/org/xerial/snappy/SnappyLoader.java

@@ -87,7 +87,10 @@ public class SnappyLoader
     static void cleanUpExtractedNativeLib()
     {
         if (nativeLibFile != null && nativeLibFile.exists()) {
-            nativeLibFile.delete();
+            boolean deleted = nativeLibFile.delete();
+            if (!deleted) {
+                // Deleting native lib has failed, but it's not serious so simply ignore it here
+            }
         }
     }
 
@@ -217,37 +220,50 @@ public class SnappyLoader
 
         try {
             // Extract a native library file into the target directory
-            InputStream reader = SnappyLoader.class.getResourceAsStream(nativeLibraryFilePath);
-            FileOutputStream writer = new FileOutputStream(extractedLibFile);
+            InputStream reader = null;
+            FileOutputStream writer = null;
             try {
-                byte[] buffer = new byte[8192];
-                int bytesRead = 0;
-                while ((bytesRead = reader.read(buffer)) != -1) {
-                    writer.write(buffer, 0, bytesRead);
+                reader = SnappyLoader.class.getResourceAsStream(nativeLibraryFilePath);
+                try {
+                    writer = new FileOutputStream(extractedLibFile);
+
+                    byte[] buffer = new byte[8192];
+                    int bytesRead = 0;
+                    while ((bytesRead = reader.read(buffer)) != -1) {
+                        writer.write(buffer, 0, bytesRead);
+                    }
+                }
+                finally {
+                    if (writer != null) {
+                        writer.close();
+                    }
                 }
             }
             finally {
-                // Delete the extracted lib file on JVM exit.
-                extractedLibFile.deleteOnExit();
-
-                if (writer != null) {
-                    writer.close();
-                }
                 if (reader != null) {
                     reader.close();
                 }
+
+                // Delete the extracted lib file on JVM exit.
+                extractedLibFile.deleteOnExit();
             }
 
             // Set executable (x) flag to enable Java to load the native library
-            extractedLibFile.setReadable(true);
-            extractedLibFile.setWritable(true, true);
-            extractedLibFile.setExecutable(true);
+            boolean success = extractedLibFile.setReadable(true) &&
+                    extractedLibFile.setWritable(true, true) &&
+                    extractedLibFile.setExecutable(true);
+            if (!success) {
+                // Setting file flag may fail, but in this case another error will be thrown in later phase
+            }
 
             // Check whether the contents are properly copied from the resource folder
             {
-                InputStream nativeIn = SnappyLoader.class.getResourceAsStream(nativeLibraryFilePath);
-                InputStream extractedLibIn = new FileInputStream(extractedLibFile);
+                InputStream nativeIn = null;
+                InputStream extractedLibIn = null;
                 try {
+                    nativeIn = SnappyLoader.class.getResourceAsStream(nativeLibraryFilePath);
+                    extractedLibIn = new FileInputStream(extractedLibFile);
+
                     if (!contentsEquals(nativeIn, extractedLibIn)) {
                         throw new SnappyError(SnappyErrorCode.FAILED_TO_LOAD_NATIVE_LIBRARY, String.format("Failed to write a native library file at %s", extractedLibFile));
                     }
@@ -318,7 +334,10 @@ public class SnappyLoader
         // Temporary folder for the native lib. Use the value of org.xerial.snappy.tempdir or java.io.tmpdir
         File tempFolder = new File(System.getProperty(KEY_SNAPPY_TEMPDIR, System.getProperty("java.io.tmpdir")));
         if (!tempFolder.exists()) {
-            tempFolder.mkdir();
+            boolean created = tempFolder.mkdirs();
+            if (!created) {
+                // if created == false, it will fail eventually in the later part
+            }
         }
 
         // Extract and load a native library inside the jar file

src/main/java/org/xerial/snappy/SnappyOutputStream.java

@@ -86,7 +86,7 @@ public class SnappyOutputStream
      */
     public SnappyOutputStream(OutputStream out, int blockSize)
     {
-        this(out, blockSize, CachedBufferAllocator.factory);
+        this(out, blockSize, CachedBufferAllocator.getBufferAllocatorFactory());
     }
 
     public SnappyOutputStream(OutputStream out, int blockSize, BufferAllocatorFactory bufferAllocatorFactory)

src/main/java/org/xerial/snappy/buffer/CachedBufferAllocator.java

@@ -9,8 +9,7 @@ import java.util.*;
 public class CachedBufferAllocator
         implements BufferAllocator
 {
-
-    public static BufferAllocatorFactory factory = new BufferAllocatorFactory()
+    private static BufferAllocatorFactory factory = new BufferAllocatorFactory()
     {
         @Override
         public BufferAllocator getBufferAllocator(int bufferSize)
@@ -19,10 +18,21 @@ public class CachedBufferAllocator
         }
     };
 
+    public static void setBufferAllocatorFactory(BufferAllocatorFactory factory)
+    {
+        assert (factory != null);
+        CachedBufferAllocator.factory = factory;
+    }
+
+    public static BufferAllocatorFactory getBufferAllocatorFactory()
+    {
+        return factory;
+    }
+
     /**
      * Use SoftReference so that having this queueTable does not prevent the GC of CachedBufferAllocator instances
      */
-    public static Map<Integer, SoftReference<CachedBufferAllocator>> queueTable = new HashMap<Integer, SoftReference<CachedBufferAllocator>>();
+    private static final Map<Integer, SoftReference<CachedBufferAllocator>> queueTable = new HashMap<Integer, SoftReference<CachedBufferAllocator>>();
 
     private final int bufferSize;
     private final Deque<byte[]> bufferQueue;

src/test/java/org/xerial/snappy/SnappyOutputStreamTest.java

@@ -181,7 +181,7 @@ public class SnappyOutputStreamTest
         // Regression test for issue #107, a bug where close() was non-idempotent and would release
         // its buffers to the allocator multiple times, which could cause scenarios where two open
         // SnappyOutputStreams could share the same buffers, leading to stream corruption issues.
-        final BufferAllocatorFactory bufferAllocatorFactory = CachedBufferAllocator.factory;
+        final BufferAllocatorFactory bufferAllocatorFactory = CachedBufferAllocator.getBufferAllocatorFactory();
         final int BLOCK_SIZE = 4096;
         // Create a stream, use it, then close it once:
         ByteArrayOutputStream ba1 = new ByteArrayOutputStream();