Fix truncated reads from compressed JAR data sources

sentinel-extension/sentinel-datasource-extension/src/main/java/com/alibaba/csp/sentinel/datasource/FileInJarReadableDataSource.java

@@ -100,7 +100,18 @@ public String readSource() throws Exception {
                 throw new IllegalStateException(String.format("Size of file <%s> exceeds the bufSize (%d): %d",
                     jarFile.getName(), buf.length, inputStream.available()));
             }
-            int len = inputStream.read(buf);
+            int len = 0;
+            while (len < buf.length) {
+                int read = inputStream.read(buf, len, buf.length - len);
+                if (read == -1) {
+                    break;
+                }
+                len += read;
+            }
+            if (len == buf.length && inputStream.read() != -1) {
+                throw new IllegalStateException(String.format("Size of file <%s> exceeds the bufSize (%d)",
+                    jarFile.getName(), buf.length));
+            }
             return new String(buf, 0, len, charset);
         }
     }

sentinel-extension/sentinel-datasource-extension/src/test/java/com/alibaba/csp/sentinel/datasource/FileInJarReadableDataSourceTest.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.csp.sentinel.datasource;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.reflect.Field;
+import java.nio.charset.StandardCharsets;
+import java.util.Random;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.jar.JarOutputStream;
+import java.util.zip.ZipEntry;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import static org.junit.Assert.assertEquals;
+
+public class FileInJarReadableDataSourceTest {
+
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Test
+    public void testReadCompleteCompressedEntry() throws Exception {
+        StringBuilder content = new StringBuilder();
+        Random random = new Random(0);
+        for (int i = 0; i < 65536; i++) {
+            content.append((char) ('a' + random.nextInt(26)));
+        }
+        assertReadSource(content.toString(), 65536);
+    }
+
+    @Test
+    public void testReadEmptyEntry() throws Exception {
+        assertReadSource("", 16);
+    }
+
+    @Test
+    public void testReadUtf8Entry() throws Exception {
+        String content = "{\"resource\":\"资源\"}";
+        assertReadSource(content, content.getBytes(StandardCharsets.UTF_8).length);
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testRejectEntryLargerThanBuffer() throws Exception {
+        File jar = createJar("12345678");
+        FileInJarReadableDataSource<String> dataSource = new FileInJarReadableDataSource<>(
+            jar.getAbsolutePath(), "rules.json", source -> source, 7);
+        try {
+            dataSource.readSource();
+        } finally {
+            dataSource.close();
+        }
+    }
+
+    @Test(expected = IllegalStateException.class)
+    public void testRejectEntryLargerThanBufferWhenAvailableUnderReports() throws Exception {
+        readSourceWithUnderReportingAvailable("12345678", 7);
+    }
+
+    @Test
+    public void testReadEntryFillingBufferWhenAvailableUnderReports() throws Exception {
+        assertEquals("12345678", readSourceWithUnderReportingAvailable("12345678", 8));
+    }
+
+    private String readSourceWithUnderReportingAvailable(String content, int bufferSize) throws Exception {
+        File jar = createJar(content);
+        FileInJarReadableDataSource<String> dataSource = new FileInJarReadableDataSource<>(
+            jar.getAbsolutePath(), "rules.json", source -> source, bufferSize);
+        Field jarFileField = FileInJarReadableDataSource.class.getDeclaredField("jarFile");
+        jarFileField.setAccessible(true);
+        ((JarFile) jarFileField.get(dataSource)).close();
+        try (JarFile jarFile = new JarFile(jar) {
+            @Override
+            public InputStream getInputStream(ZipEntry entry) throws IOException {
+                return new FilterInputStream(super.getInputStream(entry)) {
+                    @Override
+                    public int available() {
+                        return 0;
+                    }
+                };
+            }
+        }) {
+            jarFileField.set(dataSource, jarFile);
+            return dataSource.readSource();
+        } finally {
+            dataSource.close();
+        }
+    }
+
+    private void assertReadSource(String content, int bufferSize) throws Exception {
+        File jar = createJar(content);
+        FileInJarReadableDataSource<String> dataSource = new FileInJarReadableDataSource<>(
+            jar.getAbsolutePath(), "rules.json", source -> source, bufferSize);
+        try {
+            String source = dataSource.readSource();
+            assertEquals(content.length(), source.length());
+            assertEquals(content, source);
+            assertEquals(content, dataSource.loadConfig());
+        } finally {
+            dataSource.close();
+        }
+    }
+
+    private File createJar(String content) throws Exception {
+        File jar = temporaryFolder.newFile();
+        try (JarOutputStream output = new JarOutputStream(new FileOutputStream(jar))) {
+            output.putNextEntry(new JarEntry("rules.json"));
+            output.write(content.getBytes(StandardCharsets.UTF_8));
+            output.closeEntry();
+        }
+        return jar;
+    }
+}