netsurf/content/fetchers/resource.c
2016-05-30 11:29:39 +01:00

471 lines
12 KiB
C

/*
* Copyright 2011 Vincent Sanders <vince@netsurf-browser.org>
*
* This file is part of NetSurf.
*
* NetSurf is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* NetSurf is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* \file
* resource scheme URL handling. Based on the data fetcher by Rob Kendrick
*/
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <strings.h>
#include <stdio.h>
#include <stdarg.h>
#include <libwapcaplet/libwapcaplet.h>
#include "utils/nsurl.h"
#include "utils/corestrings.h"
#include "utils/log.h"
#include "utils/messages.h"
#include "utils/utils.h"
#include "utils/ring.h"
#include "netsurf/fetch.h"
#include "desktop/gui_internal.h"
#include "content/fetch.h"
#include "content/fetchers.h"
#include "content/fetchers/resource.h"
#define DIRECT_ETAG_VALUE 123456
/** Valid resource paths */
static const char *fetch_resource_paths[] = {
"adblock.css",
"default.css",
"internal.css",
"quirks.css",
"user.css",
"credits.html",
"licence.html",
"welcome.html",
"maps.html",
"favicon.ico",
"default.ico",
"netsurf.png",
"icons/arrow-l.png",
"icons/content.png",
"icons/directory.png",
"icons/directory2.png",
"icons/hotlist-add.png",
"icons/hotlist-rmv.png",
"icons/search.png"
};
/**
* map of resource scheme paths to redirect urls
*/
static struct fetch_resource_map_entry {
lwc_string *path; /**< resource scheme path */
nsurl *redirect_url; /**< url to redirect to */
const uint8_t *data; /**< direct pointer to data */
size_t data_len; /**< length of direct data */
} fetch_resource_map[NOF_ELEMENTS(fetch_resource_paths)];
struct fetch_resource_context;
typedef bool (*fetch_resource_handler)(struct fetch_resource_context *);
/** Context for an resource fetch */
struct fetch_resource_context {
struct fetch_resource_context *r_next, *r_prev;
struct fetch *fetchh; /**< Handle for this fetch */
bool aborted; /**< Flag indicating fetch has been aborted */
bool locked; /**< Flag indicating entry is already entered */
nsurl *url; /**< requested url */
struct fetch_resource_map_entry *entry; /**< resource map entry */
fetch_resource_handler handler;
int etag;
};
static struct fetch_resource_context *ring = NULL;
static uint32_t fetch_resource_path_count;
/** issue fetch callbacks with locking */
static inline bool fetch_resource_send_callback(const fetch_msg *msg,
struct fetch_resource_context *ctx)
{
ctx->locked = true;
fetch_send_callback(msg, ctx->fetchh);
ctx->locked = false;
return ctx->aborted;
}
static bool fetch_resource_send_header(struct fetch_resource_context *ctx,
const char *fmt, ...)
{
fetch_msg msg;
char header[64];
va_list ap;
va_start(ap, fmt);
vsnprintf(header, sizeof header, fmt, ap);
va_end(ap);
msg.type = FETCH_HEADER;
msg.data.header_or_data.buf = (const uint8_t *) header;
msg.data.header_or_data.len = strlen(header);
fetch_resource_send_callback(&msg, ctx);
return ctx->aborted;
}
/**
* resource handler that results in a redirect to another url.
*/
static bool fetch_resource_redirect_handler(struct fetch_resource_context *ctx)
{
fetch_msg msg;
/* content is going to return redirect */
fetch_set_http_code(ctx->fetchh, 302);
msg.type = FETCH_REDIRECT;
msg.data.redirect = nsurl_access(ctx->entry->redirect_url);
fetch_resource_send_callback(&msg, ctx);
return true;
}
/* resource handler that returns data directly */
static bool fetch_resource_data_handler(struct fetch_resource_context *ctx)
{
fetch_msg msg;
/* Check if we can just return not modified */
if (ctx->etag != 0 && ctx->etag == DIRECT_ETAG_VALUE) {
fetch_set_http_code(ctx->fetchh, 304);
msg.type = FETCH_NOTMODIFIED;
fetch_resource_send_callback(&msg, ctx);
return true;
}
/* fetch is going to be successful */
fetch_set_http_code(ctx->fetchh, 200);
/* Any callback can result in the fetch being aborted.
* Therefore, we _must_ check for this after _every_ call to
* fetch_file_send_callback().
*/
/* content type */
if (fetch_resource_send_header(ctx, "Content-Type: %s",
guit->fetch->filetype(lwc_string_data(ctx->entry->path)))) {
goto fetch_resource_data_aborted;
}
/* content length */
if (fetch_resource_send_header(ctx, "Content-Length: %" PRIsizet,
ctx->entry->data_len)) {
goto fetch_resource_data_aborted;
}
/* create etag */
if (fetch_resource_send_header(ctx, "ETag: \"%10" PRId64 "\"",
(int64_t) DIRECT_ETAG_VALUE)) {
goto fetch_resource_data_aborted;
}
msg.type = FETCH_DATA;
msg.data.header_or_data.buf = (const uint8_t *) ctx->entry->data;
msg.data.header_or_data.len = ctx->entry->data_len;
fetch_resource_send_callback(&msg, ctx);
if (ctx->aborted == false) {
msg.type = FETCH_FINISHED;
fetch_resource_send_callback(&msg, ctx);
}
fetch_resource_data_aborted:
return true;
}
static bool fetch_resource_notfound_handler(struct fetch_resource_context *ctx)
{
fetch_msg msg;
int code = 404;
char buffer[1024];
const char *title;
char key[8];
/* content is going to return error code */
fetch_set_http_code(ctx->fetchh, code);
/* content type */
if (fetch_resource_send_header(ctx, "Content-Type: text/html"))
goto fetch_resource_notfound_handler_aborted;
snprintf(key, sizeof key, "HTTP%03d", code);
title = messages_get(key);
snprintf(buffer, sizeof buffer, "<html><head><title>%s</title></head>"
"<body><h1>%s</h1>"
"<p>Error %d while fetching file %s</p></body></html>",
title, title, code, nsurl_access(ctx->url));
msg.type = FETCH_DATA;
msg.data.header_or_data.buf = (const uint8_t *) buffer;
msg.data.header_or_data.len = strlen(buffer);
if (fetch_resource_send_callback(&msg, ctx))
goto fetch_resource_notfound_handler_aborted;
msg.type = FETCH_FINISHED;
fetch_resource_send_callback(&msg, ctx);
fetch_resource_notfound_handler_aborted:
return false;
}
/** callback to initialise the resource fetcher. */
static bool fetch_resource_initialise(lwc_string *scheme)
{
struct fetch_resource_map_entry *e;
uint32_t i;
nserror res;
fetch_resource_path_count = 0;
for (i = 0; i < NOF_ELEMENTS(fetch_resource_paths); i++) {
e = &fetch_resource_map[fetch_resource_path_count];
if (lwc_intern_string(fetch_resource_paths[i],
strlen(fetch_resource_paths[i]),
&e->path) != lwc_error_ok) {
while (i > 0) {
i--;
lwc_string_unref(fetch_resource_map[i].path);
nsurl_unref(fetch_resource_map[i].redirect_url);
}
/** \todo should this exit with an error condition? */
}
e->data = NULL;
res = guit->fetch->get_resource_data(lwc_string_data(e->path),
&e->data,
&e->data_len);
if (res == NSERROR_OK) {
LOG("direct data for %s", fetch_resource_paths[i]);
fetch_resource_path_count++;
} else {
e->redirect_url = guit->fetch->get_resource_url(fetch_resource_paths[i]);
if (e->redirect_url == NULL) {
lwc_string_unref(e->path);
} else {
LOG("redirect url for %s", fetch_resource_paths[i]);
fetch_resource_path_count++;
}
}
}
return true;
}
/** callback to finalise the resource fetcher. */
static void fetch_resource_finalise(lwc_string *scheme)
{
uint32_t i;
for (i = 0; i < fetch_resource_path_count; i++) {
lwc_string_unref(fetch_resource_map[i].path);
if (fetch_resource_map[i].data != NULL) {
guit->fetch->release_resource_data(fetch_resource_map[i].data);
} else {
nsurl_unref(fetch_resource_map[i].redirect_url);
}
}
}
static bool fetch_resource_can_fetch(const nsurl *url)
{
return true;
}
/**
* set up a resource fetch context.
*/
static void *
fetch_resource_setup(struct fetch *fetchh,
nsurl *url,
bool only_2xx,
bool downgrade_tls,
const char *post_urlenc,
const struct fetch_multipart_data *post_multipart,
const char **headers)
{
struct fetch_resource_context *ctx;
lwc_string *path;
uint32_t i;
ctx = calloc(1, sizeof(*ctx));
if (ctx == NULL) {
return NULL;
}
ctx->handler = fetch_resource_notfound_handler;
if ((path = nsurl_get_component(url, NSURL_PATH)) != NULL) {
bool match;
/* Ensure requested path is valid */
for (i = 0; i < fetch_resource_path_count; i++) {
if (lwc_string_isequal(path,
fetch_resource_map[i].path,
&match) == lwc_error_ok && match) {
/* found a url match, select handler */
ctx->entry = &fetch_resource_map[i];
if (ctx->entry->data != NULL) {
ctx->handler = fetch_resource_data_handler;
} else {
ctx->handler = fetch_resource_redirect_handler;
}
break;
}
}
lwc_string_unref(path);
}
ctx->url = nsurl_ref(url);
/* Scan request headers looking for If-None-Match */
for (i = 0; headers[i] != NULL; i++) {
if (strncasecmp(headers[i], "If-None-Match:",
SLEN("If-None-Match:")) == 0) {
/* If-None-Match: "12345678" */
const char *d = headers[i] + SLEN("If-None-Match:");
/* Scan to first digit, if any */
while (*d != '\0' && (*d < '0' || '9' < *d))
d++;
/* Convert to time_t */
if (*d != '\0')
ctx->etag = atoi(d);
}
}
ctx->fetchh = fetchh;
RING_INSERT(ring, ctx);
return ctx;
}
/** callback to free a resource fetch */
static void fetch_resource_free(void *ctx)
{
struct fetch_resource_context *c = ctx;
if (c->url != NULL)
nsurl_unref(c->url);
RING_REMOVE(ring, c);
free(ctx);
}
/** callback to start a resource fetch */
static bool fetch_resource_start(void *ctx)
{
return true;
}
/** callback to abort a resource fetch */
static void fetch_resource_abort(void *ctx)
{
struct fetch_resource_context *c = ctx;
/* To avoid the poll loop having to deal with the fetch context
* disappearing from under it, we simply flag the abort here.
* The poll loop itself will perform the appropriate cleanup.
*/
c->aborted = true;
}
/** callback to poll for additional resource fetch contents */
static void fetch_resource_poll(lwc_string *scheme)
{
struct fetch_resource_context *c, *next;
if (ring == NULL) return;
/* Iterate over ring, processing each pending fetch */
c = ring;
do {
/* Ignore fetches that have been flagged as locked.
* This allows safe re-entrant calls to this function.
* Re-entrancy can occur if, as a result of a callback,
* the interested party causes fetch_poll() to be called
* again.
*/
if (c->locked == true) {
next = c->r_next;
continue;
}
/* Only process non-aborted fetches */
if (c->aborted == false) {
/* resource fetches can be processed in one go */
c->handler(c);
}
/* Compute next fetch item at the last possible moment
* as processing this item may have added to the ring
*/
next = c->r_next;
fetch_remove_from_queues(c->fetchh);
fetch_free(c->fetchh);
/* Advance to next ring entry, exiting if we've reached
* the start of the ring or the ring has become empty
*/
} while ( (c = next) != ring && ring != NULL);
}
nserror fetch_resource_register(void)
{
lwc_string *scheme = lwc_string_ref(corestring_lwc_resource);
const struct fetcher_operation_table fetcher_ops = {
.initialise = fetch_resource_initialise,
.acceptable = fetch_resource_can_fetch,
.setup = fetch_resource_setup,
.start = fetch_resource_start,
.abort = fetch_resource_abort,
.free = fetch_resource_free,
.poll = fetch_resource_poll,
.finalise = fetch_resource_finalise
};
return fetcher_add(scheme, &fetcher_ops);
}