From 953f2b39e1bb4d2ab256f369e8d66c4fab7e1482 Mon Sep 17 00:00:00 2001
From: Stephan Schroevers <stephan.schroevers@teampicnic.com>
Date: Tue, 23 Jan 2024 13:14:14 +0100
Subject: [PATCH] Introduce `InputStream{Read,Skip}NBytes` Refaster rules

---
 .../refasterrules/InputStreamRules.java       | 26 +++++++++++++++++--
 .../InputStreamRulesTestInput.java            |  8 ++++++
 .../InputStreamRulesTestOutput.java           |  8 ++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/InputStreamRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/InputStreamRules.java
index 6eed99b6f1..e0c635d82a 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/InputStreamRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/InputStreamRules.java
@@ -9,8 +9,6 @@
 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() {}
@@ -38,4 +36,28 @@ byte[] after(InputStream in) throws IOException {
       return in.readAllBytes();
     }
   }
+
+  static final class InputStreamReadNBytes {
+    @BeforeTemplate
+    byte[] before(InputStream in, int n) throws IOException {
+      return ByteStreams.limit(in, n).readAllBytes();
+    }
+
+    @AfterTemplate
+    byte[] after(InputStream in, int n) throws IOException {
+      return in.readNBytes(n);
+    }
+  }
+
+  static final class InputStreamSkipNBytes {
+    @BeforeTemplate
+    void before(InputStream in, long n) throws IOException {
+      ByteStreams.skipFully(in, n);
+    }
+
+    @AfterTemplate
+    void after(InputStream in, long n) throws IOException {
+      in.skipNBytes(n);
+    }
+  }
 }
diff --git a/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestInput.java b/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestInput.java
index 633bbda3dc..f31f88797b 100644
--- a/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestInput.java
+++ b/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestInput.java
@@ -20,4 +20,12 @@ long testInputStreamTransferTo() throws IOException {
   byte[] testInputStreamReadAllBytes() throws IOException {
     return ByteStreams.toByteArray(new ByteArrayInputStream(new byte[0]));
   }
+
+  byte[] testInputStreamReadNBytes() throws IOException {
+    return ByteStreams.limit(new ByteArrayInputStream(new byte[0]), 0).readAllBytes();
+  }
+
+  void testInputStreamSkipNBytes() throws IOException {
+    ByteStreams.skipFully(new ByteArrayInputStream(new byte[0]), 0);
+  }
 }
diff --git a/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestOutput.java b/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestOutput.java
index fbb99bfdb0..b52074c2e2 100644
--- a/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestOutput.java
+++ b/error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/InputStreamRulesTestOutput.java
@@ -20,4 +20,12 @@ long testInputStreamTransferTo() throws IOException {
   byte[] testInputStreamReadAllBytes() throws IOException {
     return new ByteArrayInputStream(new byte[0]).readAllBytes();
   }
+
+  byte[] testInputStreamReadNBytes() throws IOException {
+    return new ByteArrayInputStream(new byte[0]).readNBytes(0);
+  }
+
+  void testInputStreamSkipNBytes() throws IOException {
+    new ByteArrayInputStream(new byte[0]).skipNBytes(0);
+  }
 }