Track absolute position of the cursor

[folly.git] / folly / io / test / IOBufCursorTest.cpp

diff --git a/folly/io/test/IOBufCursorTest.cpp b/folly/io/test/IOBufCursorTest.cpp
index 68aa7784b1cb5d6e2231d152f60a7724bb57b959..1f013da621bf1db55d117d0e45a792280a9d3089 100644 (file)
--- a/folly/io/test/IOBufCursorTest.cpp
+++ b/folly/io/test/IOBufCursorTest.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 Facebook, Inc.
+ * Copyright 2013-present Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 #include <folly/io/IOBuf.h>
 
 #include <folly/Format.h>
@@ -142,7 +141,7 @@ TEST(IOBuf, Cursor) {
   c.write((uint8_t)40); // OK
   try {
     c.write((uint8_t)10); // Bad write, checked should except.
-    EXPECT_TRUE(false);
+    ADD_FAILURE();
   } catch (...) {
   }
 }
@@ -190,7 +189,7 @@ std::string toString(const IOBuf& buf) {
   return str;
 }
 
-}  // namespace
+} // namespace
 
 TEST(IOBuf, PullAndPeek) {
   std::unique_ptr<IOBuf> iobuf1(IOBuf::create(10));
@@ -369,6 +368,7 @@ TEST(IOBuf, cloneAndInsert) {
 
     cursor.insert(std::move(cloned));
     cursor.insert(folly::IOBuf::create(0));
+    EXPECT_EQ(4, cursor.getCurrentPosition());
     EXPECT_EQ(7, iobuf1->countChainElements());
     EXPECT_EQ(14, iobuf1->computeChainDataLength());
     // Check that nextBuf got set correctly to the buffer with 1 byte left
@@ -386,24 +386,46 @@ TEST(IOBuf, cloneAndInsert) {
     cursor.skip(1);
 
     cursor.insert(std::move(cloned));
+    EXPECT_EQ(2, cursor.getCurrentPosition());
     EXPECT_EQ(8, iobuf1->countChainElements());
     EXPECT_EQ(15, iobuf1->computeChainDataLength());
     // Check that nextBuf got set correctly
     cursor.read<uint8_t>();
   }
   {
-    // Check that inserting at the beginning doesn't create empty buf
+    // Check that inserting at the beginning of a chunk (except first one)
+    // doesn't create empty buf
     RWPrivateCursor cursor(iobuf1.get());
     Cursor(iobuf1.get()).clone(cloned, 1);
     EXPECT_EQ(1, cloned->countChainElements());
     EXPECT_EQ(1, cloned->computeChainDataLength());
 
+    cursor.skip(1);
+
     cursor.insert(std::move(cloned));
+    EXPECT_EQ(2, cursor.getCurrentPosition());
+    EXPECT_EQ(14, cursor.totalLength());
     EXPECT_EQ(9, iobuf1->countChainElements());
     EXPECT_EQ(16, iobuf1->computeChainDataLength());
     // Check that nextBuf got set correctly
     cursor.read<uint8_t>();
   }
+  {
+    // Check that inserting at the beginning of a chain DOES keep an empty
+    // buffer.
+    RWPrivateCursor cursor(iobuf1.get());
+    Cursor(iobuf1.get()).clone(cloned, 1);
+    EXPECT_EQ(1, cloned->countChainElements());
+    EXPECT_EQ(1, cloned->computeChainDataLength());
+
+    cursor.insert(std::move(cloned));
+    EXPECT_EQ(1, cursor.getCurrentPosition());
+    EXPECT_EQ(16, cursor.totalLength());
+    EXPECT_EQ(11, iobuf1->countChainElements());
+    EXPECT_EQ(17, iobuf1->computeChainDataLength());
+    // Check that nextBuf got set correctly
+    cursor.read<uint8_t>();
+  }
 }
 
 TEST(IOBuf, cloneWithEmptyBufAtStart) {
@@ -1132,3 +1154,40 @@ TEST(IOBuf, pushEmptyByteRange) {
   app.push(emptyBytes);
   EXPECT_EQ(0, buf.computeChainDataLength());
 }
+
+TEST(IOBuf, positionTracking) {
+  unique_ptr<IOBuf> iobuf1(IOBuf::create(6));
+  iobuf1->append(6);
+  unique_ptr<IOBuf> iobuf2(IOBuf::create(24));
+  iobuf2->append(24);
+  iobuf1->prependChain(std::move(iobuf2));
+
+  Cursor cursor(iobuf1.get());
+
+  EXPECT_EQ(0, cursor.getCurrentPosition());
+  EXPECT_EQ(6, cursor.length());
+
+  cursor.skip(3);
+  EXPECT_EQ(3, cursor.getCurrentPosition());
+  EXPECT_EQ(3, cursor.length());
+
+  // Test that we properly handle advancing to the next chunk.
+  cursor.skip(4);
+  EXPECT_EQ(7, cursor.getCurrentPosition());
+  EXPECT_EQ(23, cursor.length());
+
+  // Test that we properly handle doing to the previous chunk.
+  cursor.retreat(2);
+  EXPECT_EQ(5, cursor.getCurrentPosition());
+  EXPECT_EQ(1, cursor.length());
+
+  // Test that we properly handle advanceToEnd
+  cursor.advanceToEnd();
+  EXPECT_EQ(30, cursor.getCurrentPosition());
+  EXPECT_EQ(0, cursor.totalLength());
+
+  // Reset to 0.
+  cursor.reset(iobuf1.get());
+  EXPECT_EQ(0, cursor.getCurrentPosition());
+  EXPECT_EQ(30, cursor.totalLength());
+}