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root/software/photo_compress_archiver/PhotoCompressArchiver.cc @ 4f833a04

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#include <chrono>
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#include <iomanip>
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#include <iostream>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>

#include "PhotoCompressArchiver.hh"

#define OUT(x) {\
std::lock_guard<std::mutex> lock(m_output_mutex);\
x\
}

const char *PROG_NAME = "./packJPG";
const char *PROG_OPT1 = "-np";
const char *PROG_OPT2 = "-o";
const char *PROG_OPT3 = "-p";

PhotoCompressArchiver::PhotoCompressArchiver(
const char* path,
uint32_t num_cores)
: m_path(path),
m_num_cores(num_cores),
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m_files_processed(0),
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m_num_input_files(0),
m_total_uncompressed_size(0),
m_total_compressed_size(0),
p_finder_thread(nullptr)
{}

PhotoCompressArchiver::~PhotoCompressArchiver()
{}

int PhotoCompressArchiver::execute()
{
// Start the file finder thread
OUT(std::cout << "Starting file finder..." << std::flush;);
p_finder_thread = new std::thread(&PhotoCompressArchiver::find_files, this,
m_path, JPEG_REGEX);
OUT(std::cout << "DONE" << std::endl;)
p_finder_thread->join();
OUT(std::cout << "File finder completed:" << std::endl;)
OUT(std::cout << " Found " << m_num_input_files << " images" << std::endl;)
OUT(std::cout << " Total uncompressed bytes: " << m_total_uncompressed_size
<< "\n" << std::endl;)
// Start worker threads
OUT(std::cout << "Starting worker threads..." << std::endl;)
// TODO: need to handle the cause were number of input files is less than
// the number of threads
uint32_t num_threads = m_num_cores;
uint32_t sublist_len = m_num_input_files / num_threads;
for (uint32_t idx = 0; idx < num_threads; ++idx)
{
// Subdivide the input file list (using the vector copy constructor
// and start/end iterators)
decltype(m_file_list.begin()) start_iter;
decltype(m_file_list.begin()) end_iter;
if (idx == (num_threads - 1))
{
// Make sure the last sublist goes all the way to the end of the
// input file list (if number of images is not an even multiple of
// number of threads)
start_iter = m_file_list.begin() + (idx * sublist_len);
end_iter = m_file_list.end();
}
else
{
start_iter = m_file_list.begin() + (idx * sublist_len);
end_iter = m_file_list.begin() + ((idx + 1) * sublist_len);
}
auto sublist = new std::vector<bfs::path>(start_iter, end_iter);
// Spawn worker thread and add to list for bookkeeping
std::thread* worker = new std::thread(&PhotoCompressArchiver::fork_worker,
this, idx, sublist);
m_worker_threads.push_back(worker);
}
OUT(std::cout << "All worker threads started" << std::endl;)
// Clean up the finder thread
delete p_finder_thread;
p_finder_thread = nullptr;
// Now join the worker threads
for (auto worker : m_worker_threads)
{
worker->join();
delete worker;
}
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OUT(std::cout << "\n Total compressed bytes: " << m_total_compressed_size
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<< std::endl;)
// Calculate and display ratio
double ratio = (double)m_total_compressed_size / m_total_uncompressed_size;
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OUT(std::cout << " Compression ratio: " << std::fixed
<< std::setprecision(4) << (ratio * 100) << "%\n" << std::endl;)
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return 0;
}

void PhotoCompressArchiver::find_files(
const bfs::path& dir_path,
const boost::regex& file_regex)
{
bfs::directory_iterator end_iter;
for (bfs::directory_iterator dir_iter(dir_path); dir_iter != end_iter; ++dir_iter)
{
if (bfs::is_directory(dir_iter->status()))
{
// Found directory recurse
find_files(dir_iter->path(), file_regex);
}
else if (boost::regex_match(dir_iter->path().filename().string(), file_regex))
{
// Found file match
m_file_list.push_back(dir_iter->path());
++m_num_input_files;
// Stat the file to get its size
struct stat statbuf;
int rc = stat(dir_iter->path().string().c_str(), &statbuf);
if (rc)
{
OUT(std::cerr << "ERROR: unable to stat file "
<< dir_iter->path() << std::endl;)
}
m_total_uncompressed_size += statbuf.st_size;
}
}
}

void PhotoCompressArchiver::fork_worker(
uint32_t tid,
std::vector<bfs::path>* file_sublist)
{
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uint32_t sublist_file_count = file_sublist->size();
uint32_t files_processed = 0;
OUT(std::cout << "T[" << tid << "] top of the morning to ya: "
<< sublist_file_count << std::endl;)
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// Print out the input files given to this worker
#if 0
for (auto& filepath : *file_sublist)
{
OUT(std::cout << "T[" << tid << "] file: " << filepath.string()
<< std::endl;)
}
#endif
uint32_t argv_size = file_sublist->size() + 5;
const char **exec_argv = new const char* [argv_size];
// Build the argv array; pass in default program options
exec_argv[0] = &PROG_NAME[2]; // discard leading "./"
exec_argv[1] = PROG_OPT1;
exec_argv[2] = PROG_OPT2;
exec_argv[3] = PROG_OPT3;
// Add the sublist files to the argv array
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uint32_t idx = 4;
for (auto& image_path : *file_sublist)
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{
exec_argv[idx++] = image_path.string().c_str();
}
exec_argv[argv_size - 1] = nullptr;
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// Build a list of the output files names for use in output file monitoring
// below. Output file names have ".jpg" or ".jpeg" replaced with ".pjg"
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std::vector<std::string*> output_filenames;
for (auto& filepath : *file_sublist)
{
// Create new filename that contains the ".jpg" replaced with ".pjg"
uint32_t end_pos = filepath.string().find(".");
std::string* filename = new std::string(filepath.string().begin(),
filepath.string().begin() + end_pos);
(*filename) += ".pjg";
output_filenames.push_back(filename);
}
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// Create a pipe to hold stdout from child process
int filedes[2];
if (pipe(filedes) == -1)
{
perror("pipe");
exit(1);
}
// Fork off the childprocess
//~ pid_t parent = getpid();
pid_t pid = vfork();

if (pid == -1)
{
// error, failed to fork()
OUT(std::cout << "T[" << tid << "] fork failed!" << std::endl;)
}
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else if (pid == 0)
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{
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// This is the child process...
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// Set child process's stdout to the pipe entry
while ((dup2(filedes[1], STDOUT_FILENO) == -1) && (errno == EINTR)) {}
close(filedes[1]);
close(filedes[0]);
// Child after fork
execv(PROG_NAME, (char **)exec_argv);
_exit(EXIT_FAILURE); // exec never returns
}
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// This is the parent process...
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// This is a little silly... but it works. We know the order in which the
// output files will be created so we wait until output files X + 1 exists
// (i.e. we can stat() it) and then process file X.
const uint32_t BAILOUT_MAX = 600; // 30s in 50ms increments
uint32_t bailout_ctr = 0;
uint32_t output_idx = 1;
int stat_rc = 0;
struct stat statbuf;
double complete_percent = 0.0;
while (output_idx < output_filenames.size())
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{
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// Poll, waiting for output file X + 1 to exist
bailout_ctr = 0;
while ((stat(output_filenames[output_idx]->c_str(), &statbuf) != 0) &&
(++bailout_ctr < BAILOUT_MAX))
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{
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std::this_thread::sleep_for(std::chrono::milliseconds(50));
}
// Check if timeout has occurred
if (bailout_ctr == BAILOUT_MAX)
{
OUT(std::cerr << "T[" << tid << "] ERROR: timed out while waiting "
<< "for output file: "
<< *output_filenames[output_idx] << "; aborting"
<< std::endl;)
return;
}
// Now stat output file X which should exist
stat_rc = stat(output_filenames[output_idx - 1]->c_str(), &statbuf);
if (stat_rc)
{
OUT(std::cerr << "ERROR while stating: "
<< *output_filenames[output_idx - 1] << std::endl;)
}
// Increment counts
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m_total_compressed_size += statbuf.st_size;
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++m_files_processed;
++files_processed;
// Calculate the local percent done
complete_percent = (double)files_processed / sublist_file_count;
complete_percent *= 100;
OUT(std::cout << "T[" << tid << "] " << std::setw(6)
<< std::fixed << std::setprecision(2)
<< get_global_percent_done()
<< "% -- (" << files_processed << "/"
<< sublist_file_count << " -- " << std::setw(6)
<< complete_percent
<< "%) file: " << *output_filenames[output_idx - 1]
<< " -- " << statbuf.st_size << std::endl;)
++output_idx;
}
// Wait for forked child process to terminate
int status;
waitpid(pid, &status, 0);
// Now that the forked process has completed, we can handle the last output
// file
stat_rc = stat(output_filenames[output_idx - 1]->c_str(), &statbuf);
if (stat_rc)
{
OUT(std::cerr << "ERROR while stating: "
<< *output_filenames[output_idx - 1] << std::endl;)
}
// Increment counts
m_total_compressed_size += statbuf.st_size;
++m_files_processed;
++files_processed;
// Calculate the local percent done
complete_percent = (double)files_processed / sublist_file_count;
complete_percent *= 100;
OUT(std::cout << "T[" << tid << "] " << std::setw(6) << std::fixed
<< std::setprecision(2) << get_global_percent_done()
<< "% -- (" << files_processed << "/" << sublist_file_count
<< " -- " << std::setw(5) << complete_percent << "%) file: "
<< *output_filenames[output_idx - 1] << " -- "
<< statbuf.st_size << std::endl;)
OUT(std::cout << "T[" << tid << "] complete ==> RC: " << status << std::endl;)
// Free up the argv array and output filename list
delete[] exec_argv;
for (auto output_filename : output_filenames)
{
delete output_filename;
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}
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}

double PhotoCompressArchiver::get_global_percent_done()
{
return ((double)m_files_processed / m_num_input_files) * 100;
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}