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implementation: list diff operations in tree-diff-applicator

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implement the list handling primitives analogous to the
implementation of list-diff-applicator -- just again with
the additional twist to keep the attribute and child scopes
separated.
This commit is contained in:
Fischlurch 2015-10-29 04:14:18 +01:00
parent 2882d78755
commit e5ffcf224f
1 changed files with 72 additions and 4 deletions
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76
src/lib/diff/tree-diff-application.hpp
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@ -60,12 +60,14 @@
#include "lib/diff/tree-diff.hpp"
#include "lib/diff/gen-node.hpp"
#include "lib/format-string.hpp"
#include <utility>
namespace lib {
namespace diff{
using util::_Fmt;
using std::move;
using std::swap;
@ -85,11 +87,70 @@ namespace diff{
: public TreeDiffInterpreter
{
using Content = Rec::ContentMutator;
using Iter = Content::Iter;
Rec::Mutator& target_;
Content content_;
bool
end_of_target()
{
return content_.pos == content_.end();
}
void
__expect_in_target (GenNode const& elm, Literal oper)
{
if (end_of_target())
throw error::State(_Fmt("Unable to %s element %s from target as demanded; "
"no (further) elements in target sequence") % oper % elm
, LUMIERA_ERROR_DIFF_CONFLICT);
if (*content_.pos != elm)
throw error::State(_Fmt("Unable to %s element %s from target as demanded; "
"found element %s on current target position instead")
% oper % elm % *content_.pos
, LUMIERA_ERROR_DIFF_CONFLICT);
}
void
__expect_further_elements (GenNode const& elm)
{
if (end_of_target())
throw error::State(_Fmt("Premature end of target sequence, still expecting element %s; "
"unable to apply diff further.") % elm
, LUMIERA_ERROR_DIFF_CONFLICT);
}
void
__expect_found (GenNode const& elm, Iter const& targetPos)
{
if (targetPos == content_.end())
throw error::State(_Fmt("Premature end of sequence; unable to locate "
"element %s in the remainder of the target.") % elm
, LUMIERA_ERROR_DIFF_CONFLICT);
}
Iter
find_in_current_scope (GenNode const& elm)
{
Iter end_of_scope = content_.currIsAttrib()? content_.attribs.end()
: content_.children.end();
return std::find (content_.pos, end_of_scope, elm);
}
void
move_into_new_sequence (Iter pos)
{
if (content_.currIsAttrib())
target_.appendAttrib (move(*pos));
else
target_.appendChild (move(*pos));
}
/* == Implementation of the list diff application primitives == */
void
@ -108,25 +169,32 @@ namespace diff{
void
del (GenNode const& n) override
{
UNIMPLEMENTED("delete next node");
__expect_in_target(n, "remove");
++content_;
}
void
pick (GenNode const& n) override
{
UNIMPLEMENTED("accept next node as-is");
__expect_in_target(n, "pick");
move_into_new_sequence (content_.pos);
++content_;
}
void
skip (GenNode const& n) override
{
UNIMPLEMENTED("skip void position left by find");
__expect_further_elements (n);
++content_;
} // assume the actual content has been moved away by a previous find()
void
find (GenNode const& n) override
{
UNIMPLEMENTED("search the named node and insert it here");
__expect_further_elements (n);
Iter found = find_in_current_scope(n);
__expect_found (n, found);
move_into_new_sequence (found);
} // consume and leave waste, expected to be cleaned-up by skip() later