QFsFileEngine (Unix): replace a QPair with a proper struct

The comments in the declaration of the pair screamed "I want to be a
struct with properly-named member variables", and the code that read
it->first and it->second was really misleading to STL-aware readers.

Fix by defining a small struct with member names taken from unmap()'s
use of the pair's fields.

Change-Id: Ie18852a3147f65cf14cfc5a3bb633f7b3e78f5a2
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 8 insertions, 4 deletions

diff --git a/src/corelib/io/qfsfileengine_p.h b/src/corelib/io/qfsfileengine_p.h
index d6e7ecb592..f5236a0156 100644
--- a/src/corelib/io/qfsfileengine_p.h
+++ b/src/corelib/io/qfsfileengine_p.h
@@ -197,7 +197,11 @@ public:
     mutable int cachedFd;
     mutable DWORD fileAttrib;
 #else
-    QHash<uchar *, QPair<int /*offset % PageSize*/, size_t /*length + offset % PageSize*/> > maps;
+    struct StartAndLength {
+        int start;     // offset % PageSize
+        size_t length; // length + offset % PageSize
+    };
+    QHash<uchar *, StartAndLength> maps;
 #endif
     int fd;
 
diff --git a/src/corelib/io/qfsfileengine_unix.cpp b/src/corelib/io/qfsfileengine_unix.cpp
index 0b3e401be8..484a60fb74 100644
--- a/src/corelib/io/qfsfileengine_unix.cpp
+++ b/src/corelib/io/qfsfileengine_unix.cpp
@@ -621,7 +621,7 @@ uchar *QFSFileEnginePrivate::map(qint64 offset, qint64 size, QFile::MemoryMapFla
                    access, sharemode, nativeHandle(), realOffset);
     if (MAP_FAILED != mapAddress) {
         uchar *address = extra + static_cast<uchar*>(mapAddress);
-        maps[address] = QPair<int,size_t>(extra, realSize);
+        maps[address] = {extra, realSize};
         return address;
     }
 
@@ -652,8 +652,8 @@ bool QFSFileEnginePrivate::unmap(uchar *ptr)
         return false;
     }
 
-    uchar *start = ptr - it->first;
-    size_t len = it->second;
+    uchar *start = ptr - it->start;
+    size_t len = it->length;
     if (-1 == munmap(start, len)) {
         q->setError(QFile::UnspecifiedError, qt_error_string(errno));
         return false;