pdfium: remove duplication of converting a unicode string

This adds a universal getUnicodeString function that takes a
function call as a parameter, which is only a wrapped PDFium
function call that returns a unicode string. The rest of conversion
magic to OUString is then done by the function in one place.

This reduces a lot of duplication as we had to copy the way how
to convert the unicode string to OUString to every method.

Change-Id: Id951e2dd0c8b98837ca096cd5f800b8df0449fa0
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178628
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178774
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

1 files changed, 53 insertions, 128 deletions

diff --git a/vcl/source/pdf/PDFiumLibrary.cxx b/vcl/source/pdf/PDFiumLibrary.cxx
index c665ce006d9e..a1552e9ca1bf 100644
--- a/vcl/source/pdf/PDFiumLibrary.cxx
+++ b/vcl/source/pdf/PDFiumLibrary.cxx
@@ -31,6 +31,7 @@
 #include <vcl/BitmapWriteAccess.hxx>
 #include <vcl/bitmapex.hxx>
 #include <vcl/dibtools.hxx>
+#include <functional>
 
 using namespace com::sun::star;
 
@@ -220,6 +221,35 @@ int CompatibleWriterCallback(FPDF_FILEWRITE* pFileWrite, const void* pData, unsi
     pImpl->m_rStream.WriteBytes(pData, nSize);
     return 1;
 }
+
+OUString getUnicodeString(std::function<int(FPDF_WCHAR*, unsigned long)> aPDFiumFunctionCall)
+{
+    OUString sReturnText;
+
+    int nBytes = aPDFiumFunctionCall(nullptr, 0);
+    if (nBytes == 0)
+        return sReturnText;
+    assert(nBytes % 2 == 0);
+    nBytes /= 2;
+
+    std::vector<sal_Unicode> pText(nBytes, 0);
+
+    int nActualBytes = aPDFiumFunctionCall(reinterpret_cast<FPDF_WCHAR*>(pText.data()), nBytes * 2);
+    assert(nActualBytes % 2 == 0);
+    nActualBytes /= 2;
+    if (nActualBytes > 1)
+    {
+#ifdef OSL_BIGENDIAN
+        for (int i = 0; i != nActualBytes; ++i)
+        {
+            pText[i] = OSL_SWAPWORD(pText[i]);
+        }
+#endif
+        sReturnText = OUString(pText.data());
+    }
+
+    return sReturnText;
+}
 }
 
 namespace vcl::pdf
@@ -910,32 +940,10 @@ PDFiumPageObjectImpl::PDFiumPageObjectImpl(FPDF_PAGEOBJECT pPageObject)
 
 OUString PDFiumPageObjectImpl::getText(std::unique_ptr<PDFiumTextPage> const& rTextPage)
 {
-    OUString sReturnText;
-
     auto pTextPage = static_cast<PDFiumTextPageImpl*>(rTextPage.get());
-    int nBytes = FPDFTextObj_GetText(mpPageObject, pTextPage->getPointer(), nullptr, 0);
-    assert(nBytes % 2 == 0);
-    nBytes /= 2;
-
-    std::unique_ptr<sal_Unicode[]> pText(new sal_Unicode[nBytes]);
-
-    int nActualBytes = FPDFTextObj_GetText(mpPageObject, pTextPage->getPointer(),
-                                           reinterpret_cast<FPDF_WCHAR*>(pText.get()), nBytes * 2);
-    assert(nActualBytes % 2 == 0);
-    nActualBytes /= 2;
-    if (nActualBytes > 1)
-    {
-#if defined OSL_BIGENDIAN
-        // The data returned by FPDFTextObj_GetText is documented to always be UTF-16LE:
-        for (int i = 0; i != nActualBytes; ++i)
-        {
-            pText[i] = OSL_SWAPWORD(pText[i]);
-        }
-#endif
-        sReturnText = OUString(pText.get());
-    }
-
-    return sReturnText;
+    return getUnicodeString([this, pTextPage](FPDF_WCHAR* buffer, unsigned long length) {
+        return FPDFTextObj_GetText(mpPageObject, pTextPage->getPointer(), buffer, length);
+    });
 }
 
 PDFPageObjectType PDFiumPageObjectImpl::getType()
@@ -1390,98 +1398,36 @@ Color PDFiumAnnotationImpl::getFontColor(PDFiumDocument* pDoc)
 
 OUString PDFiumAnnotationImpl::getFormFieldAlternateName(PDFiumDocument* pDoc)
 {
-    auto pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
-    OUString aString;
-    unsigned long nSize = FPDFAnnot_GetFormFieldAlternateName(pDocImpl->getFormHandlePointer(),
-                                                              mpAnnotation, nullptr, 0);
-    assert(nSize % 2 == 0);
-    nSize /= 2;
-    if (nSize > 1)
-    {
-        std::unique_ptr<sal_Unicode[]> pText(new sal_Unicode[nSize]);
-        unsigned long nStringSize = FPDFAnnot_GetFormFieldAlternateName(
-            pDocImpl->getFormHandlePointer(), mpAnnotation,
-            reinterpret_cast<FPDF_WCHAR*>(pText.get()), nSize * 2);
-        assert(nStringSize % 2 == 0);
-        nStringSize /= 2;
-        if (nStringSize > 0)
-        {
-#if defined OSL_BIGENDIAN
-            for (unsigned long i = 0; i != nStringSize; ++i)
-            {
-                pText[i] = OSL_SWAPWORD(pText[i]);
-            }
-#endif
-            aString = OUString(pText.get());
-        }
-    }
-    return aString;
+    auto* pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
+    return getUnicodeString([this, pDocImpl](FPDF_WCHAR* buffer, unsigned long length) {
+        return FPDFAnnot_GetFormFieldAlternateName(pDocImpl->getFormHandlePointer(), mpAnnotation,
+                                                   buffer, length);
+    });
 }
 
 OUString PDFiumAnnotationImpl::getFormFieldValue(PDFiumDocument* pDoc)
 {
-    auto pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
-    OUString aString;
-    unsigned long nSize
-        = FPDFAnnot_GetFormFieldValue(pDocImpl->getFormHandlePointer(), mpAnnotation, nullptr, 0);
-    assert(nSize % 2 == 0);
-    nSize /= 2;
-    if (nSize > 1)
-    {
-        std::unique_ptr<sal_Unicode[]> pText(new sal_Unicode[nSize]);
-        unsigned long nStringSize
-            = FPDFAnnot_GetFormFieldValue(pDocImpl->getFormHandlePointer(), mpAnnotation,
-                                          reinterpret_cast<FPDF_WCHAR*>(pText.get()), nSize * 2);
-        assert(nStringSize % 2 == 0);
-        nStringSize /= 2;
-        if (nStringSize > 0)
-        {
-#if defined OSL_BIGENDIAN
-            for (unsigned long i = 0; i != nStringSize; ++i)
-            {
-                pText[i] = OSL_SWAPWORD(pText[i]);
-            }
-#endif
-            aString = OUString(pText.get());
-        }
-    }
-    return aString;
+    auto* pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
+    return getUnicodeString([this, pDocImpl](FPDF_WCHAR* buffer, unsigned long length) {
+        return FPDFAnnot_GetFormFieldValue(pDocImpl->getFormHandlePointer(), mpAnnotation, buffer,
+                                           length);
+    });
 }
 int PDFiumAnnotationImpl::getOptionCount(PDFiumDocument* pDoc)
 {
-    auto pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
+    auto* pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
     return FPDFAnnot_GetOptionCount(pDocImpl->getFormHandlePointer(), mpAnnotation);
 }
 
 OUString PDFiumAnnotationImpl::getFormAdditionalActionJavaScript(PDFiumDocument* pDoc,
                                                                  PDFAnnotAActionType eEvent)
 {
-    auto pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
-    OUString aString;
-    unsigned long nSize = FPDFAnnot_GetFormAdditionalActionJavaScript(
-        pDocImpl->getFormHandlePointer(), mpAnnotation, static_cast<int>(eEvent), nullptr, 0);
-    assert(nSize % 2 == 0);
-    nSize /= 2;
-    if (nSize > 1)
-    {
-        std::unique_ptr<sal_Unicode[]> pText(new sal_Unicode[nSize]);
-        unsigned long nStringSize = FPDFAnnot_GetFormAdditionalActionJavaScript(
-            pDocImpl->getFormHandlePointer(), mpAnnotation, static_cast<int>(eEvent),
-            reinterpret_cast<FPDF_WCHAR*>(pText.get()), nSize * 2);
-        assert(nStringSize % 2 == 0);
-        nStringSize /= 2;
-        if (nStringSize > 0)
-        {
-#if defined OSL_BIGENDIAN
-            for (unsigned long i = 0; i != nStringSize; ++i)
-            {
-                pText[i] = OSL_SWAPWORD(pText[i]);
-            }
-#endif
-            aString = OUString(pText.get());
-        }
-    }
-    return aString;
+    auto* pDocImpl = static_cast<PDFiumDocumentImpl*>(pDoc);
+    return getUnicodeString([this, pDocImpl, eEvent](FPDF_WCHAR* buffer, unsigned long length) {
+        return FPDFAnnot_GetFormAdditionalActionJavaScript(pDocImpl->getFormHandlePointer(),
+                                                           mpAnnotation, static_cast<int>(eEvent),
+                                                           buffer, length);
+    });
 }
 
 namespace
@@ -1539,30 +1485,9 @@ PDFObjectType PDFiumAnnotationImpl::getValueType(OString const& rKey)
 
 OUString PDFiumAnnotationImpl::getString(OString const& rKey)
 {
-    OUString rString;
-    unsigned long nSize = FPDFAnnot_GetStringValue(mpAnnotation, rKey.getStr(), nullptr, 0);
-    assert(nSize % 2 == 0);
-    nSize /= 2;
-    if (nSize > 1)
-    {
-        std::unique_ptr<sal_Unicode[]> pText(new sal_Unicode[nSize]);
-        unsigned long nStringSize = FPDFAnnot_GetStringValue(
-            mpAnnotation, rKey.getStr(), reinterpret_cast<FPDF_WCHAR*>(pText.get()), nSize * 2);
-        assert(nStringSize % 2 == 0);
-        nStringSize /= 2;
-        if (nStringSize > 0)
-        {
-#if defined OSL_BIGENDIAN
-            // The data returned by FPDFAnnot_GetStringValue is documented to always be UTF-16LE:
-            for (unsigned long i = 0; i != nStringSize; ++i)
-            {
-                pText[i] = OSL_SWAPWORD(pText[i]);
-            }
-#endif
-            rString = OUString(pText.get());
-        }
-    }
-    return rString;
+    return getUnicodeString([this, rKey](FPDF_WCHAR* buffer, unsigned long length) {
+        return FPDFAnnot_GetStringValue(mpAnnotation, rKey.getStr(), buffer, length);
+    });
 }
 
 std::vector<std::vector<basegfx::B2DPoint>> PDFiumAnnotationImpl::getInkStrokes()