From 482cb2ded5002e673e58b64907a1b51ca0baf07e Mon Sep 17 00:00:00 2001
From: Kevin Backhouse <kevinbackhouse@github.com>
Date: Sun, 26 Sep 2021 15:52:58 +0100
Subject: [PATCH] Clarify ownership model of CiffComponent::pData_

---
 src/crwimage_int.cpp | 16 ++++------------
 src/crwimage_int.hpp | 18 +++++++++++++-----
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/src/crwimage_int.cpp b/src/crwimage_int.cpp
index d007ad0e..71cb8347 100644
--- a/src/crwimage_int.cpp
+++ b/src/crwimage_int.cpp
@@ -176,9 +176,7 @@ namespace Exiv2 {
     }
 
     CiffComponent::~CiffComponent()
-    {
-        if (isAllocated_) delete[] pData_;
-    }
+    {}
 
     CiffDirectory::~CiffDirectory()
     {
@@ -560,15 +558,9 @@ namespace Exiv2 {
 
     void CiffComponent::setValue(DataBuf buf)
     {
-        if (isAllocated_) {
-            delete[] pData_;
-            pData_ = nullptr;
-            size_ = 0;
-        }
-        isAllocated_ = true;
-        std::pair<byte *, long> p = buf.release();
-        pData_ = p.first;
-        size_  = p.second;
+        storage_ = buf;
+        pData_ = storage_.c_data();
+        size_  = storage_.size();
         if (size_ > 8 && dataLocation() == directoryData) {
             tag_ &= 0x3fff;
         }
diff --git a/src/crwimage_int.hpp b/src/crwimage_int.hpp
index 884a3ed0..97d2401a 100644
--- a/src/crwimage_int.hpp
+++ b/src/crwimage_int.hpp
@@ -87,12 +87,12 @@ namespace Exiv2 {
         //@{
         //! Default constructor
         CiffComponent()
-            : dir_(0), tag_(0), size_(0), offset_(0), pData_(0),
-              isAllocated_(false) {}
+            : dir_(0), tag_(0), size_(0), offset_(0), pData_(0)
+        {}
         //! Constructor taking a tag and directory
         CiffComponent(uint16_t tag, uint16_t dir)
-            : dir_(dir), tag_(tag), size_(0), offset_(0), pData_(0),
-              isAllocated_(false) {}
+            : dir_(dir), tag_(tag), size_(0), offset_(0), pData_(0)
+        {}
         //! Virtual destructor.
         virtual ~CiffComponent();
         //@}
@@ -287,9 +287,17 @@ namespace Exiv2 {
         uint16_t    tag_;         //!< Tag of the entry
         uint32_t    size_;        //!< Size of the data area
         uint32_t    offset_;      //!< Offset to the data area from start of dir
+
+        // Notes on the ownership model of pData_: pData_ is a always a read-only
+        // pointer to a buffer owned by somebody else. Usually it is a pointer
+        // into a copy of the image that was memory-mapped in CrwImage::readMetadata().
+        // However, if CiffComponent::setValue() is used, then it is a pointer into
+        // the storage_ DataBuf below.
         const byte* pData_;       //!< Pointer to the data area
-        bool        isAllocated_; //!< True if this entry owns the value data
 
+        // This DataBuf is only used when CiffComponent::setValue is called.
+        // Otherwise, it remains empty.
+        DataBuf storage_;
     }; // class CiffComponent
 
     /*!