MSO lockfiles: Deduplicate MSO lock file reading code

The removed code was extracted to MSODocumentLockFile class
so use that class here too.
Use openStreamNoLock() for reading MSO lockfiles, because otherwise
we can not read lock files written by MSO.

Change-Id: Ib31cb9f3783d0b0ce784f900821047b9d32156f2
Reviewed-on: https://gerrit.libreoffice.org/69759
Tested-by: Jenkins
Reviewed-by: Tamás Zolnai <tamas.zolnai@collabora.com>
(cherry picked from commit ad47e9b1)
Reviewed-on: https://gerrit.libreoffice.org/69844Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>

include/svl/documentlockfile.hxx

@@ -53,7 +53,7 @@ public:
 
 protected:
     virtual void WriteEntryToStream( const LockFileEntry& aEntry, const css::uno::Reference< css::io::XOutputStream >& xStream ) = 0;
-    css::uno::Reference< css::io::XInputStream > OpenStream();
+    virtual css::uno::Reference< css::io::XInputStream > OpenStream();
 };
 
 /// Class implementing reading and writing LO lockfiles.

include/svl/msodocumentlockfile.hxx

@@ -64,6 +64,8 @@ protected:
     WriteEntryToStream(const LockFileEntry& aEntry,
                        const css::uno::Reference<css::io::XOutputStream>& xStream) override;
 
+    virtual css::uno::Reference<css::io::XInputStream> OpenStream() override;
+
 public:
     MSODocumentLockFile(const OUString& aOrigURL);
     virtual ~MSODocumentLockFile() override;

sfx2/source/doc/docfile.cxx

@@ -839,84 +839,22 @@ void SfxMedium::SetEncryptionDataToStorage_Impl()
 
 namespace
 {
-OUString tryMSOwnerFile(const INetURLObject& aLockfileURL)
+
+OUString tryMSOwnerFiles(const OUString& sDocURL)
 {
+    svt::MSODocumentLockFile aMSOLockFile(sDocURL);
+    LockFileEntry aData;
     try
     {
-        static osl::Mutex aMutex;
-        osl::MutexGuard aGuard(aMutex);
-        css::uno::Reference<css::ucb::XCommandEnvironment> xEnv;
-        ucbhelper::Content aSourceContent(
-            aLockfileURL.GetMainURL(INetURLObject::DecodeMechanism::NONE), xEnv,
-            comphelper::getProcessComponentContext());
-
-        // Excel creates Owner Files with FILE_FLAG_DELETE_ON_CLOSE, so we need to open it with
-        // FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE share mode
-        css::uno::Reference<css::io::XInputStream> xStream = aSourceContent.openStreamNoLock();
-        if (!xStream)
-            return OUString();
-
-        const sal_Int32 nBufLen = 256;
-        css::uno::Sequence<sal_Int8> aBuf(nBufLen);
-        const sal_Int32 nRead = xStream->readBytes(aBuf, nBufLen);
-        xStream->closeInput();
-        if (nRead >= 162)
-        {
-            // Reverse engineering of MS Office Owner Files format (MS Office 2016 tested).
-            // It starts with a single byte with name length, after which characters of username go
-            // in current Windows 8-bit codepage.
-            // For Word lockfiles, the name is followed by zero bytes up to position 54.
-            // For PowerPoint lockfiles, the name is followed by a single zero byte, and then 0x20
-            // bytes up to position 55.
-            // For Excel lockfiles, the name is followed by 0x20 bytes up to position 55.
-            // At those positions in each type of lockfile, a name length 2-byte word goes, followed
-            // by UTF-16-LE-encoded copy of username. Spaces or some garbage follow up to the end of
-            // the lockfile (total 162 bytes for Word, 165 bytes for Excel/PowerPoint).
-            // Apparently MS Office does not allow username to be longer than 52 characters (trying
-            // to enter more in its options dialog results in error messages stating this limit).
-            const int nACPLen = aBuf[0];
-            if (nACPLen > 0 && nACPLen <= 52) // skip wrong format
-            {
-                const sal_Int8* pBuf = aBuf.getConstArray() + 54;
-                int nUTF16Len = *pBuf; // try Word position
-                // If UTF-16 length is 0x20, then ACP length is also less than maximal, which means
-                // that in Word lockfile case, at least two preceeding bytes would be zero. Both
-                // Excel and PowerPoint lockfiles would have at least one of those bytes non-zero.
-                if (nUTF16Len == 0x20 && (*(pBuf - 1) != 0 || *(pBuf - 2) != 0))
-                    nUTF16Len = *++pBuf; // use Excel/PowerPoint position
-
-                if (nUTF16Len > 0 && nUTF16Len <= 52) // skip wrong format
-                    return OUString(reinterpret_cast<const sal_Unicode*>(pBuf + 2), nUTF16Len);
-            }
-        }
+        aData = aMSOLockFile.GetLockData();
     }
-    catch (...) {} // we don't ever need to care about any exceptions here
-
-    return OUString();
-}
-
-OUString tryMSOwnerFiles(const OUString& sDocURL)
-{
-    INetURLObject aURL(sDocURL);
-    if (aURL.HasError())
-        return OUString();
-    const OUString sFileName = aURL.GetLastName(INetURLObject::DecodeMechanism::WithCharset);
-    if (sFileName.isEmpty())
-        return OUString();
-    const OUString sFileExt = aURL.GetFileExtension();
-    const sal_Int32 nFileNameLen
-        = sFileName.getLength() - sFileExt.getLength() - (sFileExt.isEmpty() ? 0 : 1);
-    // Word, Excel, PowerPoint all prepend the filename with "~$".
-    aURL.SetName("~$" + sFileName, INetURLObject::EncodeMechanism::All);
-    OUString sUserData = tryMSOwnerFile(aURL);
-    // Additionally, Word strips first chars of the filename: 1 for length 7, 2 for length >=8.
-    if (sUserData.isEmpty() && nFileNameLen > 6)
+    catch( const uno::Exception& )
     {
-        aURL.SetName("~$" + sFileName.copy((nFileNameLen == 7) ? 1 : 2),
-                     INetURLObject::EncodeMechanism::All);
-        sUserData = tryMSOwnerFile(aURL);
+        return OUString();
     }
 
+    OUString sUserData = aData[LockFileComponent::OOOUSERNAME];
+
     if (!sUserData.isEmpty())
         sUserData += " (MS Office)"; // Mention the used office suite
 

svl/source/misc/msodocumentlockfile.cxx

@@ -11,10 +11,13 @@
 #include <rtl/ustring.hxx>
 #include <sal/log.hxx>
 #include <algorithm>
+#include <ucbhelper/content.hxx>
+#include <comphelper/processfactory.hxx>
 
 #include <com/sun/star/io/IOException.hpp>
 #include <com/sun/star/io/XOutputStream.hpp>
 #include <com/sun/star/io/XInputStream.hpp>
+#include <com/sun/star/ucb/XCommandEnvironment.hpp>
 
 namespace svt
 {
@@ -179,6 +182,17 @@ void MSODocumentLockFile::WriteEntryToStream(
     xOutput->writeBytes(aData);
 }
 
+css::uno::Reference<css::io::XInputStream> MSODocumentLockFile::OpenStream()
+{
+    ::osl::MutexGuard aGuard(m_aMutex);
+
+    css::uno::Reference<css::ucb::XCommandEnvironment> xEnv;
+    ::ucbhelper::Content aSourceContent(GetURL(), xEnv, comphelper::getProcessComponentContext());
+
+    // the file can be opened readonly, no locking will be done
+    return aSourceContent.openStreamNoLock();
+}
+
 LockFileEntry MSODocumentLockFile::GetLockData()
 {
     ::osl::MutexGuard aGuard(m_aMutex);