[cubemap] / input.cpp

#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <assert.h>
#include <arpa/inet.h>
#include <curl/curl.h>
#include <sys/socket.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/epoll.h>
#include <errno.h>
#include <vector>
#include <string>
#include <map>

#include "metacube.h"
#include "mutexlock.h"
#include "input.h"
#include "server.h"

using namespace std;

extern Server *servers;

Input::Input(const string &stream_id, const string &url)
        : stream_id(stream_id),
          url(url),
          has_metacube_header(false)
{
}

void Input::run()
{
        should_stop = false;
        
        // Joinable is already the default, but it's good to be certain.
        pthread_attr_t attr;
        pthread_attr_init(&attr);
        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
        pthread_create(&worker_thread, &attr, Input::do_work_thunk, this);
}

void Input::stop()
{
        should_stop = true;

        if (pthread_join(worker_thread, NULL) == -1) {
                perror("pthread_join");
                exit(1);
        }
}

void *Input::do_work_thunk(void *arg)
{
        Input *input = static_cast<Input *>(arg);
        input->do_work();
        return NULL;
}

void Input::do_work()
{
        CURL *curl = curl_easy_init();

        while (!should_stop) {
                curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
                curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &Input::curl_callback_thunk);
                curl_easy_setopt(curl, CURLOPT_WRITEDATA, this);
                curl_easy_perform(curl);
                if (!should_stop) {
                        printf("Transfer ended, waiting 0.2 seconds and restarting...\n");
                        usleep(200000);
                }
        }
}

size_t Input::curl_callback_thunk(char *ptr, size_t size, size_t nmemb, void *userdata)
{
        Input *input = static_cast<Input *>(userdata);
        if (input->should_stop) {
                return 0;
        }

        size_t bytes = size * nmemb;
        input->curl_callback(ptr, bytes);       
        return bytes;
}
        
void Input::curl_callback(char *ptr, size_t bytes)
{
        pending_data.insert(pending_data.end(), ptr, ptr + bytes);

        for ( ;; ) {
                // If we don't have enough data (yet) for even the Metacube header, just return.
                if (pending_data.size() < sizeof(metacube_block_header)) {
                        return;
                }

                // Make sure we have the Metacube sync header at the start.
                // We may need to skip over junk data (it _should_ not happen, though).
                if (!has_metacube_header) {
                        char *ptr = static_cast<char *>(
                                memmem(pending_data.data(), pending_data.size(),
                                       METACUBE_SYNC, strlen(METACUBE_SYNC)));
                        if (ptr == NULL) {
                                // OK, so we didn't find the sync marker. We know then that
                                // we do not have the _full_ marker in the buffer, but we
                                // could have N-1 bytes. Drop everything before that,
                                // and then give up.
                                drop_pending_data(pending_data.size() - (strlen(METACUBE_SYNC) - 1));
                                return;
                        } else {
                                // Yay, we found the header. Drop everything (if anything) before it.
                                drop_pending_data(ptr - pending_data.data());
                                has_metacube_header = true;

                                // Re-check that we have the entire header; we could have dropped data.
                                if (pending_data.size() < sizeof(metacube_block_header)) {
                                        return;
                                }
                        }
                }

                // Now it's safe to read the header.
                metacube_block_header *hdr = reinterpret_cast<metacube_block_header *>(pending_data.data());    
                assert(memcmp(hdr->sync, METACUBE_SYNC, sizeof(hdr->sync)) == 0);
                uint32_t size = ntohl(hdr->size);
                uint32_t flags = ntohl(hdr->flags);

                // See if we have the entire block. If not, wait for more data.
                if (pending_data.size() < sizeof(metacube_block_header) + size) {
                        return;
                }

                process_block(pending_data.data() + sizeof(metacube_block_header), size, flags);

                // Consume this block. This isn't the most efficient way of dealing with things
                // should we have many blocks, but these routines don't need to be too efficient
                // anyway.
                pending_data.erase(pending_data.begin(), pending_data.begin() + sizeof(metacube_block_header) + size);
                has_metacube_header = false;
        }
}
                
void Input::process_block(const char *data, uint32_t size, uint32_t flags)
{       
        if (flags & METACUBE_FLAGS_HEADER) {
                string header(data, data + size);
                for (int i = 0; i < NUM_SERVERS; ++i) {
                        servers[i].set_header(stream_id, header);
                }
        } else { 
                for (int i = 0; i < NUM_SERVERS; ++i) {
                        servers[i].add_data(stream_id, data, size);
                }
        }
}

void Input::drop_pending_data(size_t num_bytes)
{
        if (num_bytes == 0) {
                return;
        }
        fprintf(stderr, "Warning: Dropping %lld junk bytes from stream, maybe it is not a Metacube stream?\n",
                (long long)num_bytes);
        pending_data.erase(pending_data.begin(), pending_data.begin() + num_bytes);
}