mirror of https://github.com/JakubMelka/PDF4QT.git
117 lines
4.4 KiB
C++
117 lines
4.4 KiB
C++
// Copyright (C) 2018-2019 Jakub Melka
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//
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// This file is part of PdfForQt.
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//
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// PdfForQt is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// PdfForQt is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with PDFForQt. If not, see <https://www.gnu.org/licenses/>.
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#ifndef PDFDOCUMENTREADER_H
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#define PDFDOCUMENTREADER_H
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#include "pdfglobal.h"
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#include "pdfdocument.h"
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#include "pdfprogress.h"
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#include <QtCore>
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#include <QIODevice>
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namespace pdf
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{
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/// This class is a reader of PDF document from various devices (file, io device,
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/// byte buffer). This class doesn't throw exceptions, to check errors, use
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/// appropriate functions.
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class PDFFORQTLIBSHARED_EXPORT PDFDocumentReader
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{
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Q_DECLARE_TR_FUNCTIONS(pdf::PDFDocumentReader)
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public:
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explicit PDFDocumentReader(PDFProgress* progress, const std::function<QString(bool*)>& getPasswordCallback);
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constexpr inline PDFDocumentReader(const PDFDocumentReader&) = delete;
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constexpr inline PDFDocumentReader(PDFDocumentReader&&) = delete;
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constexpr inline PDFDocumentReader& operator=(const PDFDocumentReader&) = delete;
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constexpr inline PDFDocumentReader& operator=(PDFDocumentReader&&) = delete;
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enum class Result
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{
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OK, ///< Document was successfully loaded
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Failed, ///< Error occured during document reading
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Cancelled ///< User cancelled document reading
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};
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/// Reads a PDF document from the specified file. If file doesn't exist,
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/// cannot be opened or contain invalid pdf, empty PDF file is returned.
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/// No exception is thrown.
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PDFDocument readFromFile(const QString& fileName);
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/// Reads a PDF document from the specified device. If device is not opened
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/// for reading, then function tries it to open for reading. If it is opened,
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/// but not for reading, empty PDF document is returned. This also occurs
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/// when incorrect PDF is read. No exception is thrown.
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PDFDocument readFromDevice(QIODevice* device);
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/// Reads a PDF document from the specified buffer (byte array). If incorrect
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/// PDF is read, then empty PDF document is returned. No exception is thrown.
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PDFDocument readFromBuffer(const QByteArray& buffer);
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/// Returns result code for reading document from the device
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Result getReadingResult() const { return m_result; }
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/// Returns error message, if document reading was unsuccessfull
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const QString& getErrorMessage() const { return m_errorMessage; }
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private:
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static constexpr const int FIND_NOT_FOUND_RESULT = -1;
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/// Resets the internal state and prepares it for new reading cycle
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void reset();
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/// Find a last string in the byte array, scan only \p limit bytes. If string
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/// is not found, then FIND_NOT_FOUND_RESULT is returned, if it is found, then
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/// it position from the beginning of byte array is returned.
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/// \param what String to be found
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/// \param byteArray Byte array to be scanned from the end
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/// \param limit Scan up to this value bytes from the end
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/// \returns Position of string, or FIND_NOT_FOUND_RESULT
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int findFromEnd(const char* what, const QByteArray& byteArray, int limit);
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void progressStart(size_t stepCount);
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void progressStep();
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void progressFinish();
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/// Mutex for access to variables of this reader from more threads
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/// (providing thread safety)
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QMutex m_mutex;
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/// Result of document reading from the device
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std::atomic<Result> m_result;
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/// In case if error occurs, it is stored here
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QString m_errorMessage;
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/// Version of the scanned file
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PDFVersion m_version;
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/// Callback to obtain password from the user
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std::function<QString(bool*)> m_getPasswordCallback;
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/// Progress indicator
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PDFProgress* m_progress;
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};
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} // namespace pdf
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#endif // PDFDOCUMENTREADER_H
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