clean up UNO available() implementations

There seems to be some confusion here. available() is actually the
number of bytes that can be read without blocking, but most
implementations seems to be just returning the number of bytes remaining
in the stream. Since we're doing that, let's do it properly.

(*) some of them were just casting, instead of clamping, which will
return wrong values sometimes.
(*) FileStreamWrapper_Impl/OInputStreamWrapper/OTempFileService were
doing unnecessary work, instead of just asking the underlying SvStream
for it's remaining size

Change-Id: I3ef26e0363e989ed3e00be0fdb993e1cdeb7819f
Reviewed-on: https://gerrit.libreoffice.org/57264
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

13 files changed, 23 insertions, 32 deletions

diff --git a/comphelper/source/streaming/memorystream.cxx b/comphelper/source/streaming/memorystream.cxx
index b85701c30321..39b2fa0a63c5 100644
--- a/comphelper/source/streaming/memorystream.cxx
+++ b/comphelper/source/streaming/memorystream.cxx
@@ -150,7 +150,7 @@ void SAL_CALL UNOMemoryStream::skipBytes( sal_Int32 nBytesToSkip )
 
 sal_Int32 SAL_CALL UNOMemoryStream::available()
 {
-    return static_cast< sal_Int32 >( maData.size() ) - mnCursor;
+    return std::min<sal_Int64>( SAL_MAX_INT32, maData.size() - mnCursor);
 }
 
 void SAL_CALL UNOMemoryStream::closeInput()
diff --git a/comphelper/source/streaming/oslfile2streamwrap.cxx b/comphelper/source/streaming/oslfile2streamwrap.cxx
index 342c4a907e08..198ff1ecea12 100644
--- a/comphelper/source/streaming/oslfile2streamwrap.cxx
+++ b/comphelper/source/streaming/oslfile2streamwrap.cxx
@@ -120,8 +120,7 @@ sal_Int32 SAL_CALL OSLInputStreamWrapper::available()
     eError = m_pFile->setPos(osl_Pos_Absolut, nPos);
     if (eError != FileBase::E_None)
        throw css::io::NotConnectedException(OUString(),static_cast<css::uno::XWeak*>(this));
-    return sal::static_int_cast< sal_Int32 >(
-        std::max(nAvailable, sal::static_int_cast< sal_uInt64 >(SAL_MAX_INT32)));
+    return std::min<sal_Int64>(nAvailable, SAL_MAX_INT32);
 }
 
 
diff --git a/package/source/zippackage/ZipPackageBuffer.cxx b/package/source/zippackage/ZipPackageBuffer.cxx
index 8df0f3a96c9b..741c86629038 100644
--- a/package/source/zippackage/ZipPackageBuffer.cxx
+++ b/package/source/zippackage/ZipPackageBuffer.cxx
@@ -76,7 +76,7 @@ void SAL_CALL ZipPackageBuffer::skipBytes( sal_Int32 nBytesToSkip )
 }
 sal_Int32 SAL_CALL ZipPackageBuffer::available(  )
 {
-    return static_cast < sal_Int32 > (m_nEnd - m_nCurrent);
+    return std::min<sal_Int64>(SAL_MAX_INT32, m_nEnd - m_nCurrent);
 }
 void SAL_CALL ZipPackageBuffer::closeInput(  )
 {
diff --git a/sot/source/sdstor/ucbstorage.cxx b/sot/source/sdstor/ucbstorage.cxx
index d7ffbbf7a756..a9780879e907 100644
--- a/sot/source/sdstor/ucbstorage.cxx
+++ b/sot/source/sdstor/ucbstorage.cxx
@@ -203,17 +203,10 @@ sal_Int32 SAL_CALL FileStreamWrapper_Impl::available()
     ::osl::MutexGuard aGuard( m_aMutex );
     checkConnected();
 
-    sal_uInt32 nPos = m_pSvStream->Tell();
-    checkError();
-
-    m_pSvStream->Seek(STREAM_SEEK_TO_END);
-    checkError();
-
-    sal_Int32 nAvailable = static_cast<sal_Int32>(m_pSvStream->Tell()) - nPos;
-    m_pSvStream->Seek(nPos);
+    sal_Int64 nAvailable = m_pSvStream->remainingSize();
     checkError();
 
-    return nAvailable;
+    return std::min<sal_Int64>(SAL_MAX_INT32, nAvailable);
 }
 
 
diff --git a/ucb/source/ucp/cmis/std_inputstream.cxx b/ucb/source/ucp/cmis/std_inputstream.cxx
index e6a1431f8f7b..2130c3406995 100644
--- a/ucb/source/ucp/cmis/std_inputstream.cxx
+++ b/ucb/source/ucp/cmis/std_inputstream.cxx
@@ -127,7 +127,7 @@ namespace cmis
 
     sal_Int32 SAL_CALL StdInputStream::available( )
     {
-        return sal::static_int_cast< sal_Int32 >( m_nLength - getPosition() );
+        return std::min<sal_Int64>( SAL_MAX_INT32, m_nLength - getPosition() );
     }
 
     void SAL_CALL StdInputStream::closeInput( )
diff --git a/ucb/source/ucp/file/filstr.cxx b/ucb/source/ucp/file/filstr.cxx
index 69fc4aa28283..2ef94c5e6529 100644
--- a/ucb/source/ucp/file/filstr.cxx
+++ b/ucb/source/ucp/file/filstr.cxx
@@ -170,7 +170,8 @@ XStream_impl::skipBytes( sal_Int32 nBytesToSkip )
 sal_Int32 SAL_CALL
 XStream_impl::available()
 {
-    return 0;
+    sal_Int64 avail = getLength() - getPosition();
+    return std::min<sal_Int64>(avail, SAL_MAX_INT32);
 }
 
 
diff --git a/ucb/source/ucp/webdav-neon/NeonInputStream.cxx b/ucb/source/ucp/webdav-neon/NeonInputStream.cxx
index 3e43456a1838..848dc2b81cf8 100644
--- a/ucb/source/ucp/webdav-neon/NeonInputStream.cxx
+++ b/ucb/source/ucp/webdav-neon/NeonInputStream.cxx
@@ -105,7 +105,7 @@ void SAL_CALL NeonInputStream::skipBytes( sal_Int32 nBytesToSkip )
 // Returns the number of unread bytes currently remaining on the stream
 sal_Int32 SAL_CALL NeonInputStream::available(  )
 {
-    return sal::static_int_cast<sal_Int32>(mLen - mPos);
+    return std::min<sal_Int64>(SAL_MAX_INT32, mLen - mPos);
 }
 
 void SAL_CALL NeonInputStream::closeInput()
diff --git a/ucb/source/ucp/webdav/SerfInputStream.cxx b/ucb/source/ucp/webdav/SerfInputStream.cxx
index f0f954d64855..498ed26e6c24 100644
--- a/ucb/source/ucp/webdav/SerfInputStream.cxx
+++ b/ucb/source/ucp/webdav/SerfInputStream.cxx
@@ -120,7 +120,7 @@ void SAL_CALL SerfInputStream::skipBytes( sal_Int32 nBytesToSkip )
 
 sal_Int32 SAL_CALL SerfInputStream::available(  )
 {
-    return sal::static_int_cast<sal_Int32>(mLen - mPos);
+    return std::min<sal_Int64>(SAL_MAX_INT32, mLen - mPos);
 }
 
 
diff --git a/ucbhelper/source/provider/fd_inputstream.cxx b/ucbhelper/source/provider/fd_inputstream.cxx
index 32c56b40b0fa..b34e39646a4f 100644
--- a/ucbhelper/source/provider/fd_inputstream.cxx
+++ b/ucbhelper/source/provider/fd_inputstream.cxx
@@ -99,7 +99,7 @@ namespace ucbhelper
 
     sal_Int32 SAL_CALL FdInputStream::available()
     {
-        return sal::static_int_cast<sal_Int32>(m_nLength - getPosition());
+        return std::min<sal_Int64>(SAL_MAX_INT32, m_nLength - getPosition());
     }
 
 
diff --git a/unotools/source/streaming/streamwrap.cxx b/unotools/source/streaming/streamwrap.cxx
index fc68b8df300d..bcc365d961b1 100644
--- a/unotools/source/streaming/streamwrap.cxx
+++ b/unotools/source/streaming/streamwrap.cxx
@@ -107,17 +107,10 @@ sal_Int32 SAL_CALL OInputStreamWrapper::available()
     ::osl::MutexGuard aGuard( m_aMutex );
     checkConnected();
 
-    sal_uInt32 nPos = m_pSvStream->Tell();
-    checkError();
-
-    m_pSvStream->Seek(STREAM_SEEK_TO_END);
-    checkError();
-
-    sal_Int32 nAvailable = static_cast<sal_Int32>(m_pSvStream->Tell()) - nPos;
-    m_pSvStream->Seek(nPos);
+    sal_Int64 nAvailable = m_pSvStream->remainingSize();
     checkError();
 
-    return nAvailable;
+    return std::min<sal_Int64>(SAL_MAX_INT32, nAvailable);
 }
 
 void SAL_CALL OInputStreamWrapper::closeInput()
diff --git a/unotools/source/ucbhelper/xtempfile.cxx b/unotools/source/ucbhelper/xtempfile.cxx
index a9c955caf5c3..5437044b8586 100644
--- a/unotools/source/ucbhelper/xtempfile.cxx
+++ b/unotools/source/ucbhelper/xtempfile.cxx
@@ -206,11 +206,10 @@ sal_Int32 SAL_CALL OTempFileService::available(  )
 
     checkConnected();
 
-    sal_uInt32 const nAvailable =
-        static_cast<sal_uInt32>(mpStream->remainingSize());
+    sal_Int64 nAvailable = mpStream->remainingSize();
     checkError();
 
-    return nAvailable;
+    return std::min<sal_Int64>(SAL_MAX_INT32, nAvailable);
 }
 void SAL_CALL OTempFileService::closeInput(  )
 {
diff --git a/xmlhelp/source/cxxhelp/provider/inputstream.cxx b/xmlhelp/source/cxxhelp/provider/inputstream.cxx
index 19e88810799e..e5f18bb5fcc9 100644
--- a/xmlhelp/source/cxxhelp/provider/inputstream.cxx
+++ b/xmlhelp/source/cxxhelp/provider/inputstream.cxx
@@ -116,7 +116,13 @@ XInputStream_impl::skipBytes(
 sal_Int32 SAL_CALL
 XInputStream_impl::available()
 {
-    return 0;
+    sal_uInt64 uPos;
+    if( osl::FileBase::E_None != m_aFile.getPos( uPos ) )
+        throw io::IOException();
+    sal_uInt64 uSize;
+    if( osl::FileBase::E_None != m_aFile.getSize( uSize ) )
+        throw io::IOException();
+    return std::min<sal_uInt64>(SAL_MAX_INT32, uSize - uPos);
 }
 
 
diff --git a/xmlhelp/source/cxxhelp/provider/urlparameter.cxx b/xmlhelp/source/cxxhelp/provider/urlparameter.cxx
index fb0aa90cb62b..8ed8f80a1c69 100644
--- a/xmlhelp/source/cxxhelp/provider/urlparameter.cxx
+++ b/xmlhelp/source/cxxhelp/provider/urlparameter.cxx
@@ -924,7 +924,7 @@ void SAL_CALL InputStreamTransformer::skipBytes( sal_Int32 nBytesToSkip )
 sal_Int32 SAL_CALL InputStreamTransformer::available()
 {
     osl::MutexGuard aGuard( m_aMutex );
-    return std::max<sal_Int32>(buffer.getLength() - pos, 0);
+    return std::min<sal_Int64>(SAL_MAX_INT32, buffer.getLength() - pos);
 }