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#include <sys/types.h>

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#include <sys/queue.h>

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#include <stdlib.h>

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#include <stdio.h>

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#include <string.h>

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#include <event.h>

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#include <evhttp.h>

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#include "mandelbrot.h"

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#include "common.h"

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struct http_render_state {

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    struct evbuffer *buf;

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} _http_render_state = { NULL };

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int _http_render_cb (const unsigned char *data, size_t length, void *arg) {

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    // create a buffer

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    struct evbuffer *buf = evbuffer_new();

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    if (!buf) {

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        error("_http_render_cb: evbuffer_new failed");

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        return RENDER_CB_ERR;

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    }

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    // add the data to it

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    if (evbuffer_add(buf, data, length)) {

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        error("_http_render_cb: evbuffer_add(%d) failed", length);

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        return RENDER_CB_ERR;

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    }

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    // send it

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    evhttp_send_reply_chunk((struct evhttp_request *) arg, buf);

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    printf("_http_render_cb: sent chunk: %zu\n", length);

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    // free the buffer (!!!)

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    evbuffer_free(buf);

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    // return ok

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    return RENDER_CB_OK;

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}

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void http_render (struct evhttp_request *request, void *arg) {

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    // gather some info about the request

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    const char *uri = evhttp_request_uri(request);

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    char *peer_address;

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    u_short peer_port;

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    evhttp_connection_get_peer(request->evcon, &peer_address, &peer_port);

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    // request arguments

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    u_int32_t img_w = 256, img_h = 256;

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    struct evkeyval *qarg;

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    struct evkeyvalq qargs;

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    evhttp_parse_query(uri, &qargs);

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    TAILQ_FOREACH(qarg, &qargs, next) {

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        if (strcmp(qarg->key, "w") == 0)

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            img_w = strtol(qarg->value, NULL, 10);

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        else if (strcmp(qarg->key, "h") == 0)

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            img_h = strtol(qarg->value, NULL, 10);

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    }

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    // clean up the qargs (badly named functions :< )

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    evhttp_clear_headers(&qargs);

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    // request log

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    printf("REQ: [%s:%d] uri=%s, img_w=%d, img_h=%d\n", peer_address, peer_port, uri, img_w, img_h);

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    // set headers

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    evhttp_add_header(request->output_headers, "Content-Type", "image/png");

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    evhttp_send_reply_start(request, HTTP_OK, "OK");

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    // render

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    struct render_ctx ctx;

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    render_ctx_set(&ctx, &_http_render_cb, NULL, request);

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    int err = mandelbrot_render_full(&ctx, img_w, img_h);

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    if (err) {

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        fprintf(stderr, "ERR: mandelbrot_render_full(%d, %d): %d\n", img_w, img_h, err);

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    }

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    // reply end

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    evhttp_send_reply_end(request);

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}

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int main (void) {

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    // libevent/http init

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    struct event_base *ev_base = event_init();

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    if (!ev_base)

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        die("event_init");

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    struct evhttp *http_server = evhttp_new(ev_base);

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    if (!http_server)

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        die("evhttp_new");

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    // bind to the correct interface/port

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    if (evhttp_bind_socket(http_server, "0.0.0.0", 8117))

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        die("evhttp_bind_socket");

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    // add our http request handler

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    evhttp_set_cb(http_server, "/render", &http_render, NULL);

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    // we shall now run

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    printf("RUN 0.0.0.0:8117\n");

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    // run the libevent mainloop

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    if (event_dispatch())

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        die("event_dispatch");

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    // clean up

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    evhttp_free(http_server);

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    // successfull exit

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    return 0;

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}