Track absolute position of the cursor

[folly.git] / folly / io / IOBuf.h

diff --git a/folly/io/IOBuf.h b/folly/io/IOBuf.h
index 87a3ec9e78100680e9a518cca537a6f7c7760b51..0f992174575591be56020acbf5f66170eec9b0b5 100644 (file)
--- a/folly/io/IOBuf.h
+++ b/folly/io/IOBuf.h
@@ -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.
@@ -22,20 +22,21 @@
 #include <cinttypes>
 #include <cstddef>
 #include <cstring>
-#include <memory>
 #include <limits>
+#include <memory>
 #include <type_traits>
 
 #include <boost/iterator/iterator_facade.hpp>
 
 #include <folly/FBString.h>
-#include <folly/Range.h>
 #include <folly/FBVector.h>
+#include <folly/Portability.h>
+#include <folly/Range.h>
 #include <folly/portability/SysUio.h>
 
 // Ignore shadowing warnings within this file, so includers can use -Wshadow.
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wshadow"
+FOLLY_PUSH_WARNING
+FOLLY_GCC_DISABLE_WARNING("-Wshadow")
 
 namespace folly {
 
@@ -210,14 +211,11 @@ namespace folly {
  */
 namespace detail {
 // Is T a unique_ptr<> to a standard-layout type?
-template <class T, class Enable=void> struct IsUniquePtrToSL
-  : public std::false_type { };
-template <class T, class D>
-struct IsUniquePtrToSL<
-  std::unique_ptr<T, D>,
-  typename std::enable_if<std::is_standard_layout<T>::value>::type>
-  : public std::true_type { };
-}  // namespace detail
+template <typename T>
+struct IsUniquePtrToSL : std::false_type {};
+template <typename T, typename D>
+struct IsUniquePtrToSL<std::unique_ptr<T, D>> : std::is_standard_layout<T> {};
+} // namespace detail
 
 class IOBuf {
  public:
@@ -1123,6 +1121,26 @@ class IOBuf {
    */
   IOBuf cloneOneAsValue() const;
 
+  /**
+   * Return a new unchained IOBuf that may share the same data as this chain.
+   *
+   * If the IOBuf chain is not chained then the new IOBuf will point to the same
+   * underlying data buffer as the original chain. Otherwise, it will clone and
+   * coalesce the IOBuf chain.
+   *
+   * The new IOBuf will have at least as much headroom as the first IOBuf in the
+   * chain, and at least as much tailroom as the last IOBuf in the chain.
+   *
+   * Throws std::bad_alloc on error.
+   */
+  std::unique_ptr<IOBuf> cloneCoalesced() const;
+
+  /**
+   * Similar to cloneCoalesced(). But returns IOBuf by value rather than
+   * heap-allocating it.
+   */
+  IOBuf cloneCoalescedAsValue() const;
+
   /**
    * Similar to Clone(). But use other as the head node. Other nodes in the
    * chain (if any) will be allocted on heap.
@@ -1376,7 +1394,7 @@ class IOBuf {
     typedef typename UniquePtr::deleter_type Deleter;
 
     explicit UniquePtrDeleter(Deleter deleter) : deleter_(std::move(deleter)){ }
-    void dispose(void* p) {
+    void dispose(void* p) override {
       try {
         deleter_(static_cast<Pointer>(p));
         delete this;
@@ -1522,6 +1540,6 @@ class IOBuf::Iterator : public boost::iterator_facade<
 inline IOBuf::Iterator IOBuf::begin() const { return cbegin(); }
 inline IOBuf::Iterator IOBuf::end() const { return cend(); }
 
-} // folly
+} // namespace folly
 
-#pragma GCC diagnostic pop
+FOLLY_POP_WARNING