rstudio/src/cpp/core/GitGraph.cpp at master · pearsonca/rstudio · GitHub

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* GitGraph.cpp

* Unless you have received this program directly from RStudio pursuant

* to the terms of a commercial license agreement with RStudio, then

* this program is licensed to you under the terms of version 3 of the

* GNU Affero General Public License. This program is distributed WITHOUT

* ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,

* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the

* AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.

#include <limits>

#include <algorithm>

#include <core/GitGraph.hpp>

#include <shared_core/SafeConvert.hpp>

namespace rstudio {

namespace core {

namespace gitgraph {

namespace {

// If true, then this column terminates in this row's nexus.

bool isColumnTerminating(const Column& column)

{

return column.postCommit.empty();

}

// If true, then this column either starts in this row's nexus,

// ends there, or passes through it. If false, then the column

// has nothing going on in this row (well, it's possibly changing

// positions as a result of other columns being added/removed).

bool isColumnDynamic(const Column& column)

{

return column.preCommit != column.postCommit;

}

} // namespace

size_t Line::nexus() const

{

Line::const_iterator it = std::find_if(begin(), end(), &isColumnDynamic);

if (it == end())

return std::numeric_limits<size_t>::max();

else

return it - begin();

}

std::string Line::string() const

{

std::string output;

bool sawNexus = false;

for (size_t i = 0; i < size(); i++)

{

const Column& c = at(i);

if (isColumnDynamic(c))

{

if (!sawNexus)

{

sawNexus = true;

output.append("*");

}

if (c.preCommit.empty())

output.append("+");

if (c.postCommit.empty())

output.append("-");

}

output.append(safe_convert::numberToString(c.id));

if (i < size() - 1)

output.append(" ");

}

return output;

}

Line GitGraph::addCommit(const std::string& commit,

const std::vector<std::string>& parents)

{

// If this commit is a merge (has multiple parents) then we'll want to

// insert new columns immediately to the right of the existing column.

// If this commit isn't the parent of a previously seen node, then we'll

// definitely be adding one or more columns to the right of all the

// existing columns.

auto insertNewColumnsAt = pendingLine_.end();

// Counts how many of the parents have been assigned to columns.

size_t parentsUsed = 0;

for (auto it = pendingLine_.begin();

it != pendingLine_.end();

it++)

{

if (it->preCommit == commit)

{

// This column was expecting the current commit. We can either

// terminate the column here, or, we can take the first parent

// and set that as the new commit (postCommit) for this column.

// We can only do the latter once, as we want all of the columns

// for this commit to converge on one point in the graph.

// This if clause is what ensures we'll only do this once.

if (insertNewColumnsAt == pendingLine_.end())

{

// If this is a merge, we'll insert the other branches just

// to the right of us.

insertNewColumnsAt = it + 1;

// Either assign the first parent to this, or if this is an

// unparented commit (e.g. initial commit in a repo) then just

// terminate here.

if (parentsUsed == parents.size())

it->postCommit = "";

else

it->postCommit = parents[parentsUsed++];

}

else

{

it->postCommit = "";

}

// Make new columns for any parents we haven't already used.

while (parentsUsed != parents.size())

{

insertNewColumnsAt = 1 + pendingLine_.insert(

insertNewColumnsAt,

Column(nextColumnId_++, "", parents[parentsUsed++]));

}

// This line is ready. Make a copy of it.

Line result = pendingLine_;

* Now fix up pendingLine_ to get ready for the next call to addCommit.

// First remove all columns that have empty postCommit--these terminated.

auto newEnd = std::remove_if(

pendingLine_.begin(), pendingLine_.end(), &isColumnTerminating);

pendingLine_.erase(newEnd, pendingLine_.end());

// Now copy all of the postCommits to preCommit.

for (auto& column : pendingLine_)

{

column.preCommit = column.postCommit;

}

return result;

}

} // namespace gitgraph

} // namespace core

} // namespace rstudio

rstudio/src/cpp/core/GitGraph.cpp at master · pearsonca/rstudio · GitHub

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