DiffModel.h++

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#ifndef __libquark_diff_DiffModel_hxx
#define __libquark_diff_DiffModel_hxx

#include <QObject>
#include <QScopedPointer>
#include <QTextStream>
#include <QVector>

#include <quark/DiffChunk.h++>
#include <quark/DiffResult.h++>
#include <quark/DiffTypes.h++>
#include <quark/MutableObject.h++>

namespace quark {
namespace diff {

class DiffModel : public quark::util::MutableObject {
  Q_OBJECT;

  public:

  DiffModel();
  ~DiffModel();

  // Perform a 2-way diff. Takes as input the "base" (old) text and the "yours"
  // (new) text. Emits the dataChanged() signal once the diff has been
  // computed.
  void diff2(const QString& baseText, const QString& yoursText);

  // Perform a 3-way diff. Takes as input the "base", "theirs", and "yours"
  // texts. Emits the dataChanged() signal once the diff has been
  // computed.
  void diff3(const QString& theirsText, const QString& baseText,
             const QString& yoursText);

  // Set the conflict marker that introduces the "theirs" elements. For line-
  // based diffs, this string should include a trailing newline.
  inline void setTheirsConflictMarker(const QString& marker)
  { _theirsConflictMarker = marker; }

  // Set the conflict marker that introduces the "base" elements. For line-
  // based diffs, this string should include a trailing newline.
  inline void setBaseConflictMarker(const QString& marker)
  { _baseConflictMarker = marker; }

  // Set the conflict marker that introduces the "yours" elements. For line-
  // based diffs, this string should include a trailing newline.
  inline void setYoursConflictMarker(const QString& marker)
  { _yoursConflictMarker = marker; }

  // Set the conflict end marker. For line-based diffs, this string should
  // include a trailing newline.
  inline void setEndConflictMarker(const QString& marker)
  { _endConflictMarker = marker; }

  // Return the sequence length for the given role.
  int sequenceLength(DiffRole role) const;

  // Test if this is a two-way diff.
  bool isTwoWay() const;

  // Test if this is a three-way diff.
  bool isThreeWay() const;

  // Test if the model is empty.
  bool isEmpty() const;

  // Clear the model.
  void clear();

  const QVector<DiffChunk*>* diffChunks() const;

  // Return a pointer to the DiffChunk that contains the given line, or
  // NULL if there is no such chunk. line is 1-based.
  const DiffChunk* chunkForIndex(DiffRole role, int index) const;

  // Output a merge to the supplied stream. If the current model represents
  // a 2-way diff, this simply outputs the "yours" (new) file. If it is a
  // 3-way diff, it performs a 3-way merge, inserting conflict markers when
  // appropriate.
  //
  // If 'counts' is not null, it is updated to reflect the number of diff
  // edits of each type that were contributed to the resulting merge.
  bool outputMerge(QTextStream& stream, DiffCounts* counts) const;

  // Output an 'ed' script (like "diff -e"), that describes the edits from
  // the source role to the target role, to the given stream.
  void outputEdScript(DiffRole source, DiffRole destination,
                      QTextStream& stream) const;

  inline void setRecursiveDiff(bool recursiveDiff)
  { _recursiveDiff = recursiveDiff; }

  inline void setAggressiveMerge(bool aggressiveMerge)
  { _aggressiveMerge = aggressiveMerge; }

  // Dump a textual representation of the model to the debug log (for
  // debugging purposes).
  void dump(DiffDirection diffDir) const;

  private:

  void dump(DiffDirection diffDir, const DiffResult* diffResult,
            int level) const;
  void diff2(DiffResult* diffResult);
  void diff3(DiffResult* diffResult);

  // Writes the element 'range' from 'data' to the given 'stream'.
  void outputRange(const DiffRange& range, const DiffSequence& sequence,
                   QTextStream& stream) const;

  QScopedPointer<DiffResult> _diffResult;
  QString _theirsText;
  QString _baseText;
  QString _yoursText;
  QString _theirsConflictMarker;
  QString _baseConflictMarker;
  QString _yoursConflictMarker;
  QString _endConflictMarker;
  bool _recursiveDiff;
  bool _aggressiveMerge;

  Q_DISABLE_COPY(DiffModel);
};

} // namespace diff
} // namespace quark

#endif // __libquark_diff_DiffModel_hxx