osl_unmapFile can't work for files bundled inside the .apk on Android

On Android, when an app is installed, arbitrary files bundled in the
app won't be unpacked into actual separate files in the file
system. They will exist only as archive entries in the .apk file
(which is a zip archive).

The SDK tooling puts such files under the /assets folder in the
.apk. The LibreOffice bootstrapping code for Android maps the .apk
file into memory.

osl_openFile() knows about the /assets special case, and uses a
separate abstraction for such memory-mapped files.

Obviously, when producing an .apk, one needs to make sure these
bundled files are not compressed, if one wants to be able to use them
directly from the memory-mapped .apk file. We do that in our test and
sample Android projects.

When mapping such files under /assets , just return a pointer to the
file's location inside the mapped .apk archive.

We can't use the old osl_unmapFile() on such mapped files, as that
would unexpectedly unmap fairly arbitrary pages of the .apk mapping,
wreaking havoc on later use of the same pages.

So, introduce a new osl_unmapMappedFile() function that takes also the
oslFileHandle originally passed to osl_mapFile(). Use this instead in
the few places where the code actually called osl_unmapFile(). Make
sure osl_mapFile() is nonexistent on Android.

1 files changed, 9 insertions, 5 deletions

diff --git a/store/source/lockbyte.cxx b/store/source/lockbyte.cxx
index f7b20f002f7b..a91e470cc38d 100644
--- a/store/source/lockbyte.cxx
+++ b/store/source/lockbyte.cxx
@@ -476,6 +476,7 @@ struct FileMapping
 {
     sal_uInt8 * m_pAddr;
     sal_uInt32  m_nSize;
+    oslFileHandle m_hFile;
 
     FileMapping() : m_pAddr(0), m_nSize(0) {}
 
@@ -497,15 +498,17 @@ struct FileMapping
             return osl_File_E_OVERFLOW;
         m_nSize = sal::static_int_cast<sal_uInt32>(uSize);
 
+        m_hFile = hFile;
+
         // Acquire mapping.
         return osl_mapFile (hFile, reinterpret_cast<void**>(&m_pAddr), m_nSize, 0, osl_File_MapFlag_RandomAccess);
     }
 
     /** @see MappedLockBytes::destructor.
      */
-    static void unmapFile (sal_uInt8 * pAddr, sal_uInt32 nSize)
+    static void unmapFile (oslFileHandle hFile, sal_uInt8 * pAddr, sal_uInt32 nSize)
     {
-        (void) osl_unmapFile (pAddr, nSize);
+        (void) osl_unmapMappedFile (hFile, pAddr, nSize);
     }
 
     /** @see ResourceHolder<T>::destructor_type
@@ -515,7 +518,7 @@ struct FileMapping
         void operator ()(FileMapping & rMapping) const
         {
             // Release mapping.
-            unmapFile (rMapping.m_pAddr, rMapping.m_nSize);
+            unmapFile (rMapping.m_hFile, rMapping.m_pAddr, rMapping.m_nSize);
             rMapping.m_pAddr = 0, rMapping.m_nSize = 0;
         }
     };
@@ -532,6 +535,7 @@ class MappedLockBytes :
     sal_uInt8 * m_pData;
     sal_uInt32  m_nSize;
     sal_uInt16  m_nPageSize;
+    oslFileHandle m_hFile;
 
     /** PageData::Allocator implementation.
      */
@@ -577,13 +581,13 @@ protected:
 } // namespace store
 
 MappedLockBytes::MappedLockBytes (FileMapping & rMapping)
-    : m_pData (rMapping.m_pAddr), m_nSize (rMapping.m_nSize), m_nPageSize(0)
+    : m_pData (rMapping.m_pAddr), m_nSize (rMapping.m_nSize), m_nPageSize(0), m_hFile (rMapping.m_hFile)
 {
 }
 
 MappedLockBytes::~MappedLockBytes()
 {
-    FileMapping::unmapFile (m_pData, m_nSize);
+    FileMapping::unmapFile (m_hFile, m_pData, m_nSize);
 }
 
 oslInterlockedCount SAL_CALL MappedLockBytes::acquire()