lyx_mirror/src/Compare.cpp

894 lines
22 KiB
C++
Raw Normal View History

/**
* \file Compare.cpp
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author Vincent van Ravesteijn
*
* Full author contact details are available in file CREDITS.
*/
#include <config.h>
#include "Compare.h"
#include "Author.h"
#include "BufferParams.h"
#include "Changes.h"
#include "CutAndPaste.h"
#include "ErrorList.h"
#include "Font.h"
#include "insets/InsetText.h"
#include "support/docstream.h"
#include "support/lassert.h"
#include "support/lyxalgo.h"
#include "support/qstring_helpers.h"
using namespace std;
using namespace lyx::support;
namespace lyx {
enum Direction {
Forward = 0,
Backward
};
static void step(DocIterator & dit, Direction direction)
{
if (direction == Forward)
dit.top().forwardPos();
else
dit.top().backwardPos();
}
static void step(DocIterator & dit, DocIterator const & end, Direction direction)
{
if (dit != end)
step(dit, direction);
}
/**
* A pair of two DocIterators that form a range.
*/
class DocRange {
public:
DocRange(DocIterator const & from_, DocIterator const & to_)
: from(from_), to(to_)
{}
2016-06-06 19:55:39 +00:00
DocRange(Buffer const * buf) :
from(doc_iterator_begin(buf)),
to(doc_iterator_end(buf))
{
to.backwardPos();
}
///
Text * text() const { return from.text(); }
///
bool empty() const { return to <= from; }
///
size_t length() const;
/// The begin of the range
DocIterator from;
/// The end of the range
DocIterator to;
};
size_t DocRange::length() const
{
ParagraphList const & ps = from.text()->paragraphs();
size_t length = 0;
pit_type pit = from.pit();
pit_type const endpit = to.pit();
for (; pit < endpit; ++pit)
length += ps[pit].size() + 1;
length += to.pos() - from.pos();
return length;
}
class DocPair {
public:
DocPair()
{}
DocPair(DocIterator o_, DocIterator n_)
: o(o_), n(n_)
{}
bool operator!=(DocPair const & rhs)
{
// this might not be intuitive but correct for our purpose
return o != rhs.o && n != rhs.n;
}
DocPair & operator++()
{
step(o, Forward);
step(n, Forward);
return *this;
}
DocPair & operator--()
{
step(o, Backward);
step(n, Backward);
return *this;
}
///
DocIterator o;
///
DocIterator n;
};
/**
* A pair of two DocRanges.
*/
class DocRangePair {
public:
DocRangePair(DocRange const & o_, DocRange const & n_)
: o(o_), n(n_)
{}
DocRangePair(DocPair const & from, DocPair const & to)
: o(from.o, to.o), n(from.n, to.n)
{}
DocRangePair(Buffer const * o_buf, Buffer const * n_buf)
: o(o_buf), n(n_buf)
{}
/// Returns the from pair
DocPair from() const
{
return DocPair(o.from, n.from);
}
/// Returns the to pair
DocPair to() const
{
return DocPair(o.to, n.to);
}
DocRange o;
DocRange n;
};
static DocRangePair stepIntoInset(DocPair const & inset_location)
{
DocRangePair rp(inset_location, inset_location);
rp.o.from.forwardPos();
rp.n.from.forwardPos();
step(rp.o.to, Forward);
step(rp.n.to, Forward);
rp.o.to.backwardPos();
rp.n.to.backwardPos();
return rp;
}
/**
* This class is designed to hold a vector that has both positive as
* negative indices. It is internally represented as two vectors, one
* for non-zero indices and one for negative indices. In this way, the
* vector can grow in both directions.
* If an index is not available in the vector, the default value is
* returned. If an object is put in the vector beyond its size, the
* empty spots in between are also filled with the default value.
*/
template<class T>
class compl_vector {
public:
compl_vector()
{}
void reset(T const & def)
{
default_ = def;
Vp_.clear();
Vn_.clear();
}
/// Gets the value at index. If it is not in the vector
/// the default value is inserted and returned.
T & operator[](int index) {
vector<T> & V = index >= 0 ? Vp_ : Vn_;
unsigned int const ii = index >= 0 ? index : -index - 1;
while (ii >= V.size())
V.push_back(default_);
return V[ii];
}
private:
/// The vector for positive indices
vector<T> Vp_;
/// The vector for negative indices
vector<T> Vn_;
/// The default value that is inserted in the vector
/// if more space is needed
T default_;
};
/**
* The implementation of the algorithm that does the comparison
* between two documents.
*/
class Compare::Impl {
public:
///
Impl(Compare const & compare)
: abort_(false), n_(0), m_(0), offset_reverse_diagonal_(0),
odd_offset_(0), compare_(compare),
2020-02-28 06:28:08 +00:00
old_buf_(nullptr), new_buf_(nullptr), dest_buf_(nullptr),
dest_pars_(nullptr), recursion_level_(0), nested_inset_level_(0), D_(0)
{}
///
~Impl()
{}
// Algorithm to find the shortest edit string. This algorithm
// only needs a linear amount of memory (linear with the sum
// of the number of characters in the two paragraph-lists).
bool diff(Buffer const * new_buf, Buffer const * old_buf,
Buffer const * dest_buf);
/// Set to true to cancel the algorithm
bool abort_;
///
QString status()
{
QString status;
status += toqstr("recursion level:") + " " + QString::number(recursion_level_)
+ " " + toqstr("differences:") + " " + QString::number(D_);
return status;
}
private:
/// Finds the middle snake and returns the length of the
/// shortest edit script.
int findMiddleSnake(DocRangePair const & rp, DocPair & middle_snake);
enum SnakeResult {
NoSnake,
SingleSnake,
NormalSnake
};
/// Retrieve the middle snake when there is overlap between
/// the forward and backward path.
SnakeResult retrieveMiddleSnake(int k, int D, Direction direction,
DocPair & middle_snake);
2013-04-19 21:26:58 +00:00
/// Find the furthest reaching D-path (number of horizontal
/// and vertical steps; differences between the old and new
/// document) in the k-diagonal (vertical minus horizontal steps).
void furthestDpathKdiagonal(int D, int k,
DocRangePair const & rp, Direction direction);
/// Is there overlap between the forward and backward path
bool overlap(int k, int D);
/// This function is called recursively by a divide and conquer
/// algorithm. Each time, the string is divided into two split
/// around the middle snake.
void diff_i(DocRangePair const & rp);
2012-06-05 10:22:13 +00:00
/// Processes the split chunks. It either adds them as deleted,
/// as added, or call diff_i for further processing.
void diffPart(DocRangePair const & rp);
/// Runs the algorithm for the inset located at /c it and /c it_n
/// and adds the result to /c pars.
void diffInset(Inset * inset, DocPair const & p);
/// Adds the snake to the destination buffer. The algorithm will
/// recursively be applied to any InsetTexts that are within the snake.
void processSnake(DocRangePair const & rp);
/// Writes the range to the destination buffer
void writeToDestBuffer(DocRange const & range,
Change::Type type = Change::UNCHANGED);
/// Writes the paragraph list to the destination buffer
void writeToDestBuffer(ParagraphList const & copy_pars) const;
/// The length of the old chunk currently processed
int n_;
/// The length of the new chunk currently processed
int m_;
/// The offset diagonal of the reverse path of the
/// currently processed chunk
int offset_reverse_diagonal_;
/// Is the offset odd or even ?
bool odd_offset_;
/// The thread object, used to emit signals to the GUI
Compare const & compare_;
/// The buffer containing text that will be marked as old
Buffer const * old_buf_;
/// The buffer containing text that will be marked as new
Buffer const * new_buf_;
/// The buffer containing text that will be marked as new
Buffer const * dest_buf_;
/// The paragraph list of the destination buffer
ParagraphList * dest_pars_;
/// The level of recursion
int recursion_level_;
/// The number of nested insets at this level
int nested_inset_level_;
/// The position/snake in the old/new document
/// of the forward/reverse search
compl_vector<DocIterator> ofp;
compl_vector<DocIterator> nfp;
compl_vector<DocIterator> ofs;
compl_vector<DocIterator> nfs;
compl_vector<DocIterator> orp;
compl_vector<DocIterator> nrp;
compl_vector<DocIterator> ors;
compl_vector<DocIterator> nrs;
/// The number of differences in the path the algorithm
/// is currently processing.
int D_;
};
/////////////////////////////////////////////////////////////////////
//
// Compare
//
/////////////////////////////////////////////////////////////////////
Compare::Compare(Buffer const * new_buf, Buffer const * old_buf,
Buffer * const dest_buf, CompareOptions const & options)
: new_buffer(new_buf), old_buffer(old_buf), dest_buffer(dest_buf),
options_(options), pimpl_(new Impl(*this))
{
connect(&status_timer_, SIGNAL(timeout()),
this, SLOT(doStatusMessage()));
status_timer_.start(1000);
}
void Compare::doStatusMessage()
{
statusMessage(pimpl_->status());
}
void Compare::run()
{
if (!dest_buffer || !new_buffer || !old_buffer)
return;
// Copy the buffer params to the destination buffer
dest_buffer->params() = options_.settings_from_new
? new_buffer->params() : old_buffer->params();
// Copy extra authors to the destination buffer
AuthorList const & extra_authors = options_.settings_from_new ?
old_buffer->params().authors() : new_buffer->params().authors();
AuthorList::Authors::const_iterator it = extra_authors.begin();
for (; it != extra_authors.end(); ++it)
dest_buffer->params().authors().record(*it);
// We will need this later
2017-07-03 17:53:14 +00:00
DocumentClassConstPtr const olddc =
dest_buffer->params().documentClassPtr();
// We do not want to share the DocumentClass with the other Buffer.
// See bug #10295.
dest_buffer->params().makeDocumentClass();
doStatusMessage();
// Do the real work
if (!doCompare())
return;
// The comparison routine simply copies the paragraphs over into the
// new buffer with the document class from wherever they came from.
// So we need to reset the document class of all the paragraphs.
// See bug #10295.
ErrorList el;
cap::switchBetweenClasses(
olddc, dest_buffer->params().documentClassPtr(),
static_cast<InsetText &>(dest_buffer->inset()), el);
finished(pimpl_->abort_);
return;
}
int Compare::doCompare()
{
return pimpl_->diff(new_buffer, old_buffer, dest_buffer);
}
void Compare::abort()
{
pimpl_->abort_ = true;
condition_.wakeOne();
wait();
pimpl_->abort_ = false;
}
static void getParagraphList(DocRange const & range,
ParagraphList & pars)
{
// Clone the paragraphs within the selection.
pit_type startpit = range.from.pit();
pit_type endpit = range.to.pit();
ParagraphList const & ps_ = range.text()->paragraphs();
ParagraphList tmp_pars(lyx::next(ps_.begin(), startpit),
lyx::next(ps_.begin(), endpit + 1));
// Remove the end of the last paragraph; afterwards, remove the
// beginning of the first paragraph. Keep this order - there may only
// be one paragraph!
Paragraph & back = tmp_pars.back();
back.eraseChars(range.to.pos(), back.size(), false);
Paragraph & front = tmp_pars.front();
front.eraseChars(0, range.from.pos(), false);
pars.insert(pars.begin(), tmp_pars.begin(), tmp_pars.end());
}
static bool equal(Inset const * i_o, Inset const * i_n)
{
if (!i_o || !i_n)
return false;
// Different types of insets
if (i_o->lyxCode() != i_n->lyxCode())
return false;
// Editable insets are assumed to be the same as they are of the
// same type. If we later on decide that we insert them in the
// document as being unchanged, we will run the algorithm on the
// contents of the two insets.
// FIXME: This fails if the parameters of the insets differ.
// FIXME: We do not recurse into InsetTabulars.
// FIXME: We need methods inset->equivalent(inset).
if (i_o->editable() && !i_o->asInsetMath()
&& i_o->asInsetText())
return true;
ostringstream o_os;
ostringstream n_os;
i_o->write(o_os);
i_n->write(n_os);
return o_os.str() == n_os.str();
}
static bool equal(DocIterator & o, DocIterator & n)
{
// Explicitly check for this, so we won't call
// Paragraph::getChar for the last pos.
bool const o_lastpos = o.pos() == o.lastpos();
bool const n_lastpos = n.pos() == n.lastpos();
if (o_lastpos || n_lastpos)
return o_lastpos && n_lastpos;
Paragraph const & old_par = o.text()->getPar(o.pit());
Paragraph const & new_par = n.text()->getPar(n.pit());
char_type const c_o = old_par.getChar(o.pos());
char_type const c_n = new_par.getChar(n.pos());
if (c_o != c_n)
return false;
if (old_par.isInset(o.pos())) {
Inset const * i_o = old_par.getInset(o.pos());
Inset const * i_n = new_par.getInset(n.pos());
if (i_o && i_n)
return equal(i_o, i_n);
}
Font fo = old_par.getFontSettings(o.buffer()->params(), o.pos());
Font fn = new_par.getFontSettings(n.buffer()->params(), n.pos());
return fo == fn;
}
/// Traverses a snake in a certain direction. p points to a
/// position in the old and new file and they are synchronously
/// moved along the snake. The function returns true if a snake
/// was found.
static bool traverseSnake(DocPair & p, DocRangePair const & range,
Direction direction)
{
bool ret = false;
DocPair const & p_end =
direction == Forward ? range.to() : range.from();
while (p != p_end) {
if (direction == Backward)
--p;
if (!equal(p.o, p.n)) {
if (direction == Backward)
++p;
return ret;
}
if (direction == Forward)
++p;
ret = true;
}
return ret;
}
/////////////////////////////////////////////////////////////////////
//
// Compare::Impl
//
/////////////////////////////////////////////////////////////////////
void Compare::Impl::furthestDpathKdiagonal(int D, int k,
DocRangePair const & rp, Direction direction)
{
compl_vector<DocIterator> & op = direction == Forward ? ofp : orp;
compl_vector<DocIterator> & np = direction == Forward ? nfp : nrp;
compl_vector<DocIterator> & os = direction == Forward ? ofs : ors;
compl_vector<DocIterator> & ns = direction == Forward ? nfs : nrs;
// A vertical step means stepping one character in the new document.
bool vertical_step = k == -D;
if (!vertical_step && k != D) {
vertical_step = direction == Forward
? op[k - 1] < op[k + 1] : op[k - 1] > op[k + 1];
}
// Where do we take the step from ?
int const kk = vertical_step ? k + 1 : k - 1;
DocPair p(op[kk], np[kk]);
DocPair const s(os[kk], ns[kk]);
// If D==0 we simulate a vertical step from (0,-1) by doing nothing.
if (D != 0) {
// Take a step
if (vertical_step && direction == Forward)
step(p.n, rp.n.to, direction);
else if (vertical_step && direction == Backward)
step(p.n, rp.n.from, direction);
else if (!vertical_step && direction == Forward)
step(p.o, rp.o.to, direction);
else if (!vertical_step && direction == Backward)
step(p.o, rp.o.from, direction);
}
// Traverse snake
if (traverseSnake(p, rp, direction)) {
// Record last snake
os[k] = p.o;
ns[k] = p.n;
} else {
// Copy last snake from the previous step
os[k] = s.o;
ns[k] = s.n;
}
//Record new position
op[k] = p.o;
np[k] = p.n;
}
bool Compare::Impl::overlap(int k, int D)
{
// To generalize for the forward and reverse checks
int kk = offset_reverse_diagonal_ - k;
// Can we have overlap ?
if (kk <= D && kk >= -D) {
// Do we have overlap ?
if (odd_offset_)
return ofp[k] >= orp[kk] && nfp[k] >= nrp[kk];
else
return ofp[kk] >= orp[k] && nfp[kk] >= nrp[k];
}
return false;
}
Compare::Impl::SnakeResult Compare::Impl::retrieveMiddleSnake(
int k, int D, Direction direction, DocPair & middle_snake)
{
compl_vector<DocIterator> & os = direction == Forward ? ofs : ors;
compl_vector<DocIterator> & ns = direction == Forward ? nfs : nrs;
compl_vector<DocIterator> & os_r = direction == Forward ? ors : ofs;
compl_vector<DocIterator> & ns_r = direction == Forward ? nrs : nfs;
// The diagonal while doing the backward search
int kk = -k + offset_reverse_diagonal_;
// Did we find a snake ?
if (os[k].empty() && os_r[kk].empty()) {
// No, there is no snake at all, in which case
// the length of the shortest edit script is M+N.
LATTEST(2 * D - odd_offset_ == m_ + n_);
return NoSnake;
}
if (os[k].empty()) {
// Yes, but there is only 1 snake and we found it in the
// reverse path.
middle_snake.o = os_r[kk];
middle_snake.n = ns_r[kk];
return SingleSnake;
}
middle_snake.o = os[k];
middle_snake.n = ns[k];
return NormalSnake;
}
int Compare::Impl::findMiddleSnake(DocRangePair const & rp,
DocPair & middle_snake)
{
// The lengths of the old and new chunks.
n_ = rp.o.length();
m_ = rp.n.length();
// Forward paths are centered around the 0-diagonal; reverse paths
// are centered around the diagonal N - M. (Delta in the article)
offset_reverse_diagonal_ = n_ - m_;
// If the offset is odd, only check for overlap while extending forward
// paths, otherwise only check while extending reverse paths.
odd_offset_ = (offset_reverse_diagonal_ % 2 != 0);
ofp.reset(rp.o.from);
nfp.reset(rp.n.from);
ofs.reset(DocIterator());
nfs.reset(DocIterator());
orp.reset(rp.o.to);
nrp.reset(rp.n.to);
ors.reset(DocIterator());
nrs.reset(DocIterator());
// In the formula below, the "+ 1" ensures we round like ceil()
int const D_max = (m_ + n_ + 1)/2;
// D is the number of horizontal and vertical steps, i.e.
// different characters in the old and new chunk.
for (int D = 0; D <= D_max; ++D) {
// to be used in the status messages
D_ = D;
// Forward and reverse paths
for (int f = 0; f < 2; ++f) {
Direction direction = f == 0 ? Forward : Backward;
// Diagonals between -D and D can be reached by a D-path
for (int k = -D; k <= D; k += 2) {
// Find the furthest reaching D-path on this diagonal
furthestDpathKdiagonal(D, k, rp, direction);
// Only check for overlap for forward paths if the offset is odd
// and only for reverse paths if the offset is even.
if (odd_offset_ == (direction == Forward)) {
// Do the forward and backward paths overlap ?
if (overlap(k, D - odd_offset_)) {
retrieveMiddleSnake(k, D, direction, middle_snake);
return 2 * D - odd_offset_;
}
}
if (abort_)
return 0;
}
}
}
// This should never be reached
return -2;
}
bool Compare::Impl::diff(Buffer const * new_buf, Buffer const * old_buf,
Buffer const * dest_buf)
{
if (!new_buf || !old_buf || !dest_buf)
return false;
old_buf_ = old_buf;
new_buf_ = new_buf;
dest_buf_ = dest_buf;
dest_pars_ = &dest_buf->inset().asInsetText()->paragraphs();
dest_pars_->clear();
recursion_level_ = 0;
nested_inset_level_ = 0;
DocRangePair rp(old_buf_, new_buf_);
DocPair from = rp.from();
traverseSnake(from, rp, Forward);
DocRangePair const snake(rp.from(), from);
processSnake(snake);
// Start the recursive algorithm
DocRangePair rp_new(from, rp.to());
if (!rp_new.o.empty() || !rp_new.n.empty())
diff_i(rp_new);
for (pit_type p = 0; p < (pit_type)dest_pars_->size(); ++p) {
(*dest_pars_)[p].setInsetBuffers(const_cast<Buffer &>(*dest_buf));
(*dest_pars_)[p].setInsetOwner(&dest_buf_->inset());
}
return true;
}
void Compare::Impl::diff_i(DocRangePair const & rp)
{
if (abort_)
return;
// The middle snake
DocPair middle_snake;
// Divides the problem into two smaller problems, split around
// the snake in the middle.
int const L_ses = findMiddleSnake(rp, middle_snake);
// Set maximum of progress bar
if (++recursion_level_ == 1)
compare_.progressMax(L_ses);
// There are now three possibilities: the strings were the same,
// the strings were completely different, or we found a middle
// snake and we can split the string into two parts to process.
if (L_ses == 0)
// Two the same strings (this must be a very rare case, because
// usually this will be part of a snake adjacent to these strings).
writeToDestBuffer(rp.o);
else if (middle_snake.o.empty()) {
// Two totally different strings
writeToDestBuffer(rp.o, Change::DELETED);
writeToDestBuffer(rp.n, Change::INSERTED);
} else {
// Retrieve the complete snake
DocPair first_part_end = middle_snake;
traverseSnake(first_part_end, rp, Backward);
DocRangePair first_part(rp.from(), first_part_end);
DocPair second_part_begin = middle_snake;
traverseSnake(second_part_begin, rp, Forward);
DocRangePair second_part(second_part_begin, rp.to());
// Split the string in three parts:
// 1. in front of the snake
diffPart(first_part);
// 2. the snake itself, and
DocRangePair const snake(first_part.to(), second_part.from());
processSnake(snake);
// 3. behind the snake.
diffPart(second_part);
}
--recursion_level_;
}
void Compare::Impl::diffPart(DocRangePair const & rp)
{
// Is there a finite length string in both buffers, if not there
// is an empty string and we write the other one to the buffer.
if (!rp.o.empty() && !rp.n.empty())
diff_i(rp);
else if (!rp.o.empty())
writeToDestBuffer(rp.o, Change::DELETED);
else if (!rp.n.empty())
writeToDestBuffer(rp.n, Change::INSERTED);
}
void Compare::Impl::diffInset(Inset * inset, DocPair const & p)
{
// Find the dociterators for the beginning and the
// end of the inset, for the old and new document.
DocRangePair const rp = stepIntoInset(p);
// Recurse into the inset. Temporarily replace the dest_pars
// paragraph list by the paragraph list of the nested inset.
ParagraphList * backup_dest_pars = dest_pars_;
dest_pars_ = &inset->asInsetText()->text().paragraphs();
dest_pars_->clear();
++nested_inset_level_;
diff_i(rp);
--nested_inset_level_;
dest_pars_ = backup_dest_pars;
}
void Compare::Impl::processSnake(DocRangePair const & rp)
{
ParagraphList pars;
getParagraphList(rp.o, pars);
// Find insets in this paragaph list
DocPair it = rp.from();
for (; it.o < rp.o.to; ++it) {
Inset * inset = it.o.text()->getPar(it.o.pit()).getInset(it.o.pos());
if (inset && inset->editable() && inset->asInsetText()) {
// Find the inset in the paragraph list that will be pasted into
// the final document. The contents of the inset will be replaced
// by the output of the algorithm below.
pit_type const pit = it.o.pit() - rp.o.from.pit();
pos_type const pos = pit ? it.o.pos() : it.o.pos() - rp.o.from.pos();
inset = pars[pit].getInset(pos);
LASSERT(inset, continue);
diffInset(inset, it);
}
}
writeToDestBuffer(pars);
}
void Compare::Impl::writeToDestBuffer(DocRange const & range,
Change::Type type)
{
ParagraphList pars;
getParagraphList(range, pars);
pos_type size = 0;
// Set the change
ParagraphList::iterator it = pars.begin();
for (; it != pars.end(); ++it) {
it->setChange(Change(type));
size += it->size();
}
writeToDestBuffer(pars);
if (nested_inset_level_ == 0)
compare_.progress(size);
}
void Compare::Impl::writeToDestBuffer(ParagraphList const & pars) const
{
dest_pars_->insert(dest_pars_->end(), pars.begin(), pars.end());
pit_type pit = dest_pars_->size();
if (pit > 0)
mergeParagraph(dest_buf_->params(), *dest_pars_, pit - 1);
}
#include "moc_Compare.cpp"
} // namespace lyx