Introduce InputStreamRules Refaster rule collection (#963)

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/InputStreamRules.java

@@ -0,0 +1,41 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.io.ByteStreams;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with {@link InputStream}s. */
+// XXX: Add a rule for `ByteStreams.skipFully(in, n)` -> `in.skipNBytes(n)` once we have a way to
+// target JDK 12+ APIs.
+@OnlineDocumentation
+final class InputStreamRules {
+  private InputStreamRules() {}
+
+  static final class InputStreamTransferTo {
+    @BeforeTemplate
+    long before(InputStream in, OutputStream out) throws IOException {
+      return ByteStreams.copy(in, out);
+    }
+
+    @AfterTemplate
+    long after(InputStream in, OutputStream out) throws IOException {
+      return in.transferTo(out);
+    }
+  }
+
+  static final class InputStreamReadAllBytes {
+    @BeforeTemplate
+    byte[] before(InputStream in) throws IOException {
+      return ByteStreams.toByteArray(in);
+    }
+
+    @AfterTemplate
+    byte[] after(InputStream in) throws IOException {
+      return in.readAllBytes();
+    }
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/refasterrules/RefasterRulesTest.java

@@ -42,6 +42,7 @@ final class RefasterRulesTest {
           DoubleStreamRules.class,
           EqualityRules.class,
           FileRules.class,
+          InputStreamRules.class,
           ImmutableListRules.class,
           ImmutableListMultimapRules.class,
           ImmutableMapRules.class,

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestInput.java

@@ -0,0 +1,23 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.io.ByteStreams;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class InputStreamRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<Object> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(ByteStreams.class);
+  }
+
+  long testInputStreamTransferTo() throws IOException {
+    return ByteStreams.copy(new ByteArrayInputStream(new byte[0]), new ByteArrayOutputStream());
+  }
+
+  byte[] testInputStreamReadAllBytes() throws IOException {
+    return ByteStreams.toByteArray(new ByteArrayInputStream(new byte[0]));
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestOutput.java

@@ -0,0 +1,23 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.io.ByteStreams;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class InputStreamRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<Object> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(ByteStreams.class);
+  }
+
+  long testInputStreamTransferTo() throws IOException {
+    return new ByteArrayInputStream(new byte[0]).transferTo(new ByteArrayOutputStream());
+  }
+
+  byte[] testInputStreamReadAllBytes() throws IOException {
+    return new ByteArrayInputStream(new byte[0]).readAllBytes();
+  }
+}