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/***
* Copyright (C) Microsoft. All rights reserved.
* Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
*
* =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
*
* searchfile.cpp - Simple cmd line application that uses a variety of streams features to search a file,
* store the results, and write results back to a new file.
*
* =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
****/
#include "cpprest/containerstream.h"
#include "cpprest/filestream.h"
#include "cpprest/producerconsumerstream.h"
using namespace utility;
using namespace concurrency::streams;
/// <summary>
/// A convenient helper function to loop asychronously until a condition is met.
/// </summary>
pplx::task<bool> _do_while_iteration(std::function<pplx::task<bool>(void)> func)
{
pplx::task_completion_event<bool> ev;
func().then([=](bool guard) { ev.set(guard); });
return pplx::create_task(ev);
}
pplx::task<bool> _do_while_impl(std::function<pplx::task<bool>(void)> func)
{
return _do_while_iteration(func).then([=](bool guard) -> pplx::task<bool> {
if (guard)
{
return ::_do_while_impl(func);
}
else
{
return pplx::task_from_result(false);
}
});
}
pplx::task<void> do_while(std::function<pplx::task<bool>(void)> func)
{
return _do_while_impl(func).then([](bool) {});
}
/// <summary>
/// Structure used to store individual line results.
/// </summary>
typedef std::vector<std::string> matched_lines;
namespace Concurrency
{
namespace streams
{
/// <summary>
/// Parser implementation for 'matched_lines' type.
/// </summary>
template<typename CharType>
class type_parser<CharType, matched_lines>
{
public:
static pplx::task<matched_lines> parse(streambuf<CharType> buffer)
{
basic_istream<CharType> in(buffer);
auto lines = std::make_shared<matched_lines>();
return do_while([=]() {
container_buffer<std::string> line;
return in.read_line(line).then([=](const size_t bytesRead) {
if (bytesRead == 0 && in.is_eof())
{
return false;
}
else
{
lines->push_back(std::move(line.collection()));
return true;
}
});
})
.then([=]() { return matched_lines(std::move(*lines)); });
}
};
} // namespace streams
} // namespace Concurrency
/// <summary>
/// Function to create in data from a file and search for a given string writing all lines containing the string to
/// memory_buffer.
/// </summary>
static pplx::task<void> find_matches_in_file(const string_t& fileName,
const std::string& searchString,
basic_ostream<char> results)
{
return file_stream<char>::open_istream(fileName).then([=](basic_istream<char> inFile) {
auto lineNumber = std::make_shared<int>(1);
return ::do_while([=]() {
container_buffer<std::string> inLine;
return inFile.read_line(inLine).then([=](size_t bytesRead) {
if (bytesRead == 0 && inFile.is_eof())
{
return pplx::task_from_result(false);
}
else if (inLine.collection().find(searchString) != std::string::npos)
{
results.print("line ");
results.print((*lineNumber)++);
return results.print(":")
.then([=](size_t) {
container_buffer<std::string> outLine(std::move(inLine.collection()));
return results.write(outLine, outLine.collection().size());
})
.then([=](size_t) { return results.print("\r\n"); })
.then([=](size_t) { return true; });
}
else
{
++(*lineNumber);
return pplx::task_from_result(true);
}
});
})
.then([=]() {
// Close the file and results stream.
return inFile.close() && results.close();
});
});
}
/// <summary>
/// Function to write out results from matched_lines type to file
/// </summary>
static pplx::task<void> write_matches_to_file(const string_t& fileName, matched_lines results)
{
// Create a shared pointer to the matched_lines structure to copying repeatedly.
auto sharedResults = std::make_shared<matched_lines>(std::move(results));
return file_stream<char>::open_ostream(fileName, std::ios::trunc).then([=](basic_ostream<char> outFile) {
auto currentIndex = std::make_shared<size_t>(0);
return ::do_while([=]() {
if (*currentIndex >= sharedResults->size())
{
return pplx::task_from_result(false);
}
container_buffer<std::string> lineData((*sharedResults)[(*currentIndex)++]);
outFile.write(lineData, lineData.collection().size());
return outFile.print("\r\n").then([](size_t) { return true; });
})
.then([=]() { return outFile.close(); });
});
}
#ifdef _WIN32
int wmain(int argc, wchar_t* args[])
#else
int main(int argc, char* args[])
#endif
{
if (argc != 4)
{
printf("Usage: SearchFile.exe input_file search_string output_file\n");
return -1;
}
const string_t inFileName = args[1];
const std::string searchString = utility::conversions::to_utf8string(args[2]);
const string_t outFileName = args[3];
producer_consumer_buffer<char> lineResultsBuffer;
// Find all matches in file.
basic_ostream<char> outLineResults(lineResultsBuffer);
find_matches_in_file(inFileName, searchString, outLineResults)
// Write matches into custom data structure.
.then([&]() {
basic_istream<char> inLineResults(lineResultsBuffer);
return inLineResults.extract<matched_lines>();
})
// Write out stored match data to a new file.
.then([&](matched_lines lines) { return write_matches_to_file(outFileName, std::move(lines)); })
// Wait for everything to complete.
.wait();
return 0;
}
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