face: minor refactoring and Doxygen improvements

refs #3248

Change-Id: I8c44b4342b9d7b9e896dbc96fbf671d3e29bcb3c
diff --git a/src/detail/pending-interest.hpp b/src/detail/pending-interest.hpp
index bac5836..f21fc2e 100644
--- a/src/detail/pending-interest.hpp
+++ b/src/detail/pending-interest.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2015 Regents of the University of California.
+ * Copyright (c) 2013-2016 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -22,28 +22,30 @@
 #ifndef NDN_DETAIL_PENDING_INTEREST_HPP
 #define NDN_DETAIL_PENDING_INTEREST_HPP
 
-#include "../common.hpp"
 #include "../interest.hpp"
 #include "../data.hpp"
-#include "../util/time.hpp"
-#include "../util/scheduler.hpp"
-#include "../util/scheduler-scoped-event-id.hpp"
 #include "../lp/nack.hpp"
+#include "../util/scheduler-scoped-event-id.hpp"
 
 namespace ndn {
 
+/**
+ * @brief stores a pending Interest and associated callbacks
+ */
 class PendingInterest : noncopyable
 {
 public:
   /**
-   * @brief Create a new PitEntry and set the timeout based on the current time and
-   *        the Interest lifetime.
-   * @param interest shared_ptr for the Interest
-   * @param dataCallback function to call when matching Data packet is received
-   * @param nackCallback function to call when Nack matching Interest is received
-   * @param timeoutCallback function to call if Interest times out
-   * @param scheduler Scheduler instance to use to schedule a timeout event. The scheduled
-   *                  event will be automatically cancelled when pending Interest is destroyed.
+   * @brief Construct a pending Interest record
+   *
+   * The timeout is set based on the current time and the Interest lifetime.
+   * This class will invoke the timeout callback unless the record is deleted before timeout.
+   *
+   * @param interest the Interest
+   * @param dataCallback invoked when matching Data packet is received
+   * @param nackCallback invoked when Nack matching Interest is received
+   * @param timeoutCallback invoked when Interest times out
+   * @param scheduler Scheduler for scheduling the timeout event
    */
   PendingInterest(shared_ptr<const Interest> interest,
                   const DataCallback& dataCallback,
@@ -60,7 +62,7 @@
       scheduler.scheduleEvent(m_interest->getInterestLifetime() > time::milliseconds::zero() ?
                               m_interest->getInterestLifetime() :
                               DEFAULT_INTEREST_LIFETIME,
-                              bind(&PendingInterest::invokeTimeoutCallback, this));
+                              [=] { this->invokeTimeoutCallback(); });
   }
 
   /**
@@ -73,8 +75,7 @@
   }
 
   /**
-   * @brief invokes the DataCallback
-   * @note If the DataCallback is an empty function, this method does nothing.
+   * @brief invokes the Data callback
    */
   void
   invokeDataCallback(const Data& data)
@@ -83,8 +84,7 @@
   }
 
   /**
-   * @brief invokes the NackCallback
-   * @note If the NackCallback is an empty function, this method does nothing.
+   * @brief invokes the Nack callback
    */
   void
   invokeNackCallback(const lp::Nack& nack)
@@ -93,7 +93,7 @@
   }
 
   /**
-   * @brief Set cleanup function to be called after interest times out
+   * @brief Set cleanup function to be invoked when Interest times out
    */
   void
   setDeleter(const std::function<void()>& deleter)
@@ -103,8 +103,7 @@
 
 private:
   /**
-   * @brief invokes the TimeoutCallback
-   * @note If the TimeoutCallback is an empty function, this method does nothing.
+   * @brief invokes the timeout callback (if non-empty) and the deleter
    */
   void
   invokeTimeoutCallback()
@@ -126,11 +125,13 @@
   std::function<void()> m_deleter;
 };
 
-
+/**
+ * @brief Opaque type to identify a PendingInterest
+ */
 class PendingInterestId;
 
 /**
- * @brief Functor to match pending interests against PendingInterestId
+ * @brief Functor to match PendingInterestId
  */
 class MatchPendingInterestId
 {
@@ -144,14 +145,13 @@
   bool
   operator()(const shared_ptr<const PendingInterest>& pendingInterest) const
   {
-    return (reinterpret_cast<const PendingInterestId*>(
-              pendingInterest->getInterest().get()) == m_id);
+    return reinterpret_cast<const PendingInterestId*>(pendingInterest->getInterest().get()) == m_id;
   }
+
 private:
   const PendingInterestId* m_id;
 };
 
-
 } // namespace ndn
 
 #endif // NDN_DETAIL_PENDING_INTEREST_HPP