minetest/src/clientmedia.cpp
ShadowNinja 86a3c8ce56 Reduce indentation of HTTPFetchOngoing
Also clean up some related things.
2014-09-18 21:54:22 -04:00

655 lines
19 KiB
C++

/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "clientmedia.h"
#include "httpfetch.h"
#include "client.h"
#include "clientserver.h"
#include "filecache.h"
#include "hex.h"
#include "sha1.h"
#include "debug.h"
#include "log.h"
#include "porting.h"
#include "settings.h"
#include "main.h"
#include "util/serialize.h"
#include "util/string.h"
static std::string getMediaCacheDir()
{
return porting::path_user + DIR_DELIM + "cache" + DIR_DELIM + "media";
}
/*
ClientMediaDownloader
*/
ClientMediaDownloader::ClientMediaDownloader():
m_media_cache(getMediaCacheDir())
{
m_initial_step_done = false;
m_name_bound = ""; // works because "" is an invalid file name
m_uncached_count = 0;
m_uncached_received_count = 0;
m_httpfetch_caller = HTTPFETCH_DISCARD;
m_httpfetch_active = 0;
m_httpfetch_active_limit = 0;
m_httpfetch_next_id = 0;
m_httpfetch_timeout = 0;
m_outstanding_hash_sets = 0;
}
ClientMediaDownloader::~ClientMediaDownloader()
{
if (m_httpfetch_caller != HTTPFETCH_DISCARD)
httpfetch_caller_free(m_httpfetch_caller);
for (std::map<std::string, FileStatus*>::iterator it = m_files.begin();
it != m_files.end(); ++it)
delete it->second;
for (u32 i = 0; i < m_remotes.size(); ++i)
delete m_remotes[i];
}
void ClientMediaDownloader::addFile(std::string name, std::string sha1)
{
assert(!m_initial_step_done);
// if name was already announced, ignore the new announcement
if (m_files.count(name) != 0) {
errorstream << "Client: ignoring duplicate media announcement "
<< "sent by server: \"" << name << "\""
<< std::endl;
return;
}
// if name is empty or contains illegal characters, ignore the file
if (name.empty() || !string_allowed(name, TEXTURENAME_ALLOWED_CHARS)) {
errorstream << "Client: ignoring illegal file name "
<< "sent by server: \"" << name << "\""
<< std::endl;
return;
}
// length of sha1 must be exactly 20 (160 bits), else ignore the file
if (sha1.size() != 20) {
errorstream << "Client: ignoring illegal SHA1 sent by server: "
<< hex_encode(sha1) << " \"" << name << "\""
<< std::endl;
return;
}
FileStatus *filestatus = new FileStatus;
filestatus->received = false;
filestatus->sha1 = sha1;
filestatus->current_remote = -1;
m_files.insert(std::make_pair(name, filestatus));
}
void ClientMediaDownloader::addRemoteServer(std::string baseurl)
{
assert(!m_initial_step_done);
#ifdef USE_CURL
if (g_settings->getBool("enable_remote_media_server")) {
infostream << "Client: Adding remote server \""
<< baseurl << "\" for media download" << std::endl;
RemoteServerStatus *remote = new RemoteServerStatus;
remote->baseurl = baseurl;
remote->active_count = 0;
remote->request_by_filename = false;
m_remotes.push_back(remote);
}
#else
infostream << "Client: Ignoring remote server \""
<< baseurl << "\" because cURL support is not compiled in"
<< std::endl;
#endif
}
void ClientMediaDownloader::step(Client *client)
{
if (!m_initial_step_done) {
initialStep(client);
m_initial_step_done = true;
}
// Remote media: check for completion of fetches
if (m_httpfetch_active) {
bool fetched_something = false;
HTTPFetchResult fetch_result;
while (httpfetch_async_get(m_httpfetch_caller, fetch_result)) {
m_httpfetch_active--;
fetched_something = true;
// Is this a hashset (index.mth) or a media file?
if (fetch_result.request_id < m_remotes.size())
remoteHashSetReceived(fetch_result);
else
remoteMediaReceived(fetch_result, client);
}
if (fetched_something)
startRemoteMediaTransfers();
// Did all remote transfers end and no new ones can be started?
// If so, request still missing files from the minetest server
// (Or report that we have all files.)
if (m_httpfetch_active == 0) {
if (m_uncached_received_count < m_uncached_count) {
infostream << "Client: Failed to remote-fetch "
<< (m_uncached_count-m_uncached_received_count)
<< " files. Requesting them"
<< " the usual way." << std::endl;
}
startConventionalTransfers(client);
}
}
}
void ClientMediaDownloader::initialStep(Client *client)
{
// Check media cache
m_uncached_count = m_files.size();
for (std::map<std::string, FileStatus*>::iterator
it = m_files.begin();
it != m_files.end(); ++it) {
std::string name = it->first;
FileStatus *filestatus = it->second;
const std::string &sha1 = filestatus->sha1;
std::ostringstream tmp_os(std::ios_base::binary);
bool found_in_cache = m_media_cache.load(hex_encode(sha1), tmp_os);
// If found in cache, try to load it from there
if (found_in_cache) {
bool success = checkAndLoad(name, sha1,
tmp_os.str(), true, client);
if (success) {
filestatus->received = true;
m_uncached_count--;
}
}
}
assert(m_uncached_received_count == 0);
// Create the media cache dir if we are likely to write to it
if (m_uncached_count != 0) {
bool did = fs::CreateAllDirs(getMediaCacheDir());
if (!did) {
errorstream << "Client: "
<< "Could not create media cache directory: "
<< getMediaCacheDir()
<< std::endl;
}
}
// If we found all files in the cache, report this fact to the server.
// If the server reported no remote servers, immediately start
// conventional transfers. Note: if cURL support is not compiled in,
// m_remotes is always empty, so "!USE_CURL" is redundant but may
// reduce the size of the compiled code
if (!USE_CURL || m_uncached_count == 0 || m_remotes.empty()) {
startConventionalTransfers(client);
}
else {
// Otherwise start off by requesting each server's sha1 set
// This is the first time we use httpfetch, so alloc a caller ID
m_httpfetch_caller = httpfetch_caller_alloc();
m_httpfetch_timeout = g_settings->getS32("curl_timeout");
// Set the active fetch limit to curl_parallel_limit or 84,
// whichever is greater. This gives us some leeway so that
// inefficiencies in communicating with the httpfetch thread
// don't slow down fetches too much. (We still want some limit
// so that when the first remote server returns its hash set,
// not all files are requested from that server immediately.)
// One such inefficiency is that ClientMediaDownloader::step()
// is only called a couple times per second, while httpfetch
// might return responses much faster than that.
// Note that httpfetch strictly enforces curl_parallel_limit
// but at no inter-thread communication cost. This however
// doesn't help with the aforementioned inefficiencies.
// The signifance of 84 is that it is 2*6*9 in base 13.
m_httpfetch_active_limit = g_settings->getS32("curl_parallel_limit");
m_httpfetch_active_limit = MYMAX(m_httpfetch_active_limit, 84);
// Write a list of hashes that we need. This will be POSTed
// to the server using Content-Type: application/octet-stream
std::string required_hash_set = serializeRequiredHashSet();
// minor fixme: this loop ignores m_httpfetch_active_limit
// another minor fixme, unlikely to matter in normal usage:
// these index.mth fetches do (however) count against
// m_httpfetch_active_limit when starting actual media file
// requests, so if there are lots of remote servers that are
// not responding, those will stall new media file transfers.
for (u32 i = 0; i < m_remotes.size(); ++i) {
assert(m_httpfetch_next_id == i);
RemoteServerStatus *remote = m_remotes[i];
actionstream << "Client: Contacting remote server \""
<< remote->baseurl << "\"" << std::endl;
HTTPFetchRequest fetch_request;
fetch_request.url =
remote->baseurl + MTHASHSET_FILE_NAME;
fetch_request.caller = m_httpfetch_caller;
fetch_request.request_id = m_httpfetch_next_id; // == i
fetch_request.timeout = m_httpfetch_timeout;
fetch_request.connect_timeout = m_httpfetch_timeout;
fetch_request.post_data = required_hash_set;
fetch_request.extra_headers.push_back(
"Content-Type: application/octet-stream");
httpfetch_async(fetch_request);
m_httpfetch_active++;
m_httpfetch_next_id++;
m_outstanding_hash_sets++;
}
}
}
void ClientMediaDownloader::remoteHashSetReceived(
const HTTPFetchResult &fetch_result)
{
u32 remote_id = fetch_result.request_id;
assert(remote_id < m_remotes.size());
RemoteServerStatus *remote = m_remotes[remote_id];
m_outstanding_hash_sets--;
if (fetch_result.succeeded) {
try {
// Server sent a list of file hashes that are
// available on it, try to parse the list
std::set<std::string> sha1_set;
deSerializeHashSet(fetch_result.data, sha1_set);
// Parsing succeeded: For every file that is
// available on this server, add this server
// to the available_remotes array
for(std::map<std::string, FileStatus*>::iterator
it = m_files.upper_bound(m_name_bound);
it != m_files.end(); ++it) {
FileStatus *f = it->second;
if (!f->received && sha1_set.count(f->sha1))
f->available_remotes.push_back(remote_id);
}
}
catch (SerializationError &e) {
infostream << "Client: Remote server \""
<< remote->baseurl << "\" sent invalid hash set: "
<< e.what() << std::endl;
}
}
// For compatibility: If index.mth is not found, assume that the
// server contains files named like the original files (not their sha1)
// Do NOT check for any particular response code (e.g. 404) here,
// because different servers respond differently
if (!fetch_result.succeeded && !fetch_result.timeout) {
infostream << "Client: Enabling compatibility mode for remote "
<< "server \"" << remote->baseurl << "\"" << std::endl;
remote->request_by_filename = true;
// Assume every file is available on this server
for(std::map<std::string, FileStatus*>::iterator
it = m_files.upper_bound(m_name_bound);
it != m_files.end(); ++it) {
FileStatus *f = it->second;
if (!f->received)
f->available_remotes.push_back(remote_id);
}
}
}
void ClientMediaDownloader::remoteMediaReceived(
const HTTPFetchResult &fetch_result,
Client *client)
{
// Some remote server sent us a file.
// -> decrement number of active fetches
// -> mark file as received if fetch succeeded
// -> try to load media
std::string name;
{
std::map<unsigned long, std::string>::iterator it =
m_remote_file_transfers.find(fetch_result.request_id);
assert(it != m_remote_file_transfers.end());
name = it->second;
m_remote_file_transfers.erase(it);
}
assert(m_files.count(name) != 0);
FileStatus *filestatus = m_files[name];
assert(!filestatus->received);
assert(filestatus->current_remote >= 0);
RemoteServerStatus *remote = m_remotes[filestatus->current_remote];
filestatus->current_remote = -1;
remote->active_count--;
// If fetch succeeded, try to load media file
if (fetch_result.succeeded) {
bool success = checkAndLoad(name, filestatus->sha1,
fetch_result.data, false, client);
if (success) {
filestatus->received = true;
assert(m_uncached_received_count < m_uncached_count);
m_uncached_received_count++;
}
}
}
s32 ClientMediaDownloader::selectRemoteServer(FileStatus *filestatus)
{
assert(filestatus != NULL);
assert(!filestatus->received);
assert(filestatus->current_remote < 0);
if (filestatus->available_remotes.empty())
return -1;
else {
// Of all servers that claim to provide the file (and haven't
// been unsuccessfully tried before), find the one with the
// smallest number of currently active transfers
s32 best = 0;
s32 best_remote_id = filestatus->available_remotes[best];
s32 best_active_count = m_remotes[best_remote_id]->active_count;
for (u32 i = 1; i < filestatus->available_remotes.size(); ++i) {
s32 remote_id = filestatus->available_remotes[i];
s32 active_count = m_remotes[remote_id]->active_count;
if (active_count < best_active_count) {
best = i;
best_remote_id = remote_id;
best_active_count = active_count;
}
}
filestatus->available_remotes.erase(
filestatus->available_remotes.begin() + best);
return best_remote_id;
}
}
void ClientMediaDownloader::startRemoteMediaTransfers()
{
bool changing_name_bound = true;
for (std::map<std::string, FileStatus*>::iterator
files_iter = m_files.upper_bound(m_name_bound);
files_iter != m_files.end(); ++files_iter) {
// Abort if active fetch limit is exceeded
if (m_httpfetch_active >= m_httpfetch_active_limit)
break;
const std::string &name = files_iter->first;
FileStatus *filestatus = files_iter->second;
if (!filestatus->received && filestatus->current_remote < 0) {
// File has not been received yet and is not currently
// being transferred. Choose a server for it.
s32 remote_id = selectRemoteServer(filestatus);
if (remote_id >= 0) {
// Found a server, so start fetching
RemoteServerStatus *remote =
m_remotes[remote_id];
std::string url = remote->baseurl +
(remote->request_by_filename ? name :
hex_encode(filestatus->sha1));
verbosestream << "Client: "
<< "Requesting remote media file "
<< "\"" << name << "\" "
<< "\"" << url << "\"" << std::endl;
HTTPFetchRequest fetch_request;
fetch_request.url = url;
fetch_request.caller = m_httpfetch_caller;
fetch_request.request_id = m_httpfetch_next_id;
fetch_request.timeout = 0; // no data timeout!
fetch_request.connect_timeout =
m_httpfetch_timeout;
httpfetch_async(fetch_request);
m_remote_file_transfers.insert(std::make_pair(
m_httpfetch_next_id,
name));
filestatus->current_remote = remote_id;
remote->active_count++;
m_httpfetch_active++;
m_httpfetch_next_id++;
}
}
if (filestatus->received ||
(filestatus->current_remote < 0 &&
!m_outstanding_hash_sets)) {
// If we arrive here, we conclusively know that we
// won't fetch this file from a remote server in the
// future. So update the name bound if possible.
if (changing_name_bound)
m_name_bound = name;
}
else
changing_name_bound = false;
}
}
void ClientMediaDownloader::startConventionalTransfers(Client *client)
{
assert(m_httpfetch_active == 0);
if (m_uncached_received_count != m_uncached_count) {
// Some media files have not been received yet, use the
// conventional slow method (minetest protocol) to get them
std::list<std::string> file_requests;
for (std::map<std::string, FileStatus*>::iterator
it = m_files.begin();
it != m_files.end(); ++it) {
if (!it->second->received)
file_requests.push_back(it->first);
}
assert((s32) file_requests.size() ==
m_uncached_count - m_uncached_received_count);
client->request_media(file_requests);
}
}
void ClientMediaDownloader::conventionalTransferDone(
const std::string &name,
const std::string &data,
Client *client)
{
// Check that file was announced
std::map<std::string, FileStatus*>::iterator
file_iter = m_files.find(name);
if (file_iter == m_files.end()) {
errorstream << "Client: server sent media file that was"
<< "not announced, ignoring it: \"" << name << "\""
<< std::endl;
return;
}
FileStatus *filestatus = file_iter->second;
assert(filestatus != NULL);
// Check that file hasn't already been received
if (filestatus->received) {
errorstream << "Client: server sent media file that we already"
<< "received, ignoring it: \"" << name << "\""
<< std::endl;
return;
}
// Mark file as received, regardless of whether loading it works and
// whether the checksum matches (because at this point there is no
// other server that could send a replacement)
filestatus->received = true;
assert(m_uncached_received_count < m_uncached_count);
m_uncached_received_count++;
// Check that received file matches announced checksum
// If so, load it
checkAndLoad(name, filestatus->sha1, data, false, client);
}
bool ClientMediaDownloader::checkAndLoad(
const std::string &name, const std::string &sha1,
const std::string &data, bool is_from_cache, Client *client)
{
const char *cached_or_received = is_from_cache ? "cached" : "received";
const char *cached_or_received_uc = is_from_cache ? "Cached" : "Received";
std::string sha1_hex = hex_encode(sha1);
// Compute actual checksum of data
std::string data_sha1;
{
SHA1 data_sha1_calculator;
data_sha1_calculator.addBytes(data.c_str(), data.size());
unsigned char *data_tmpdigest = data_sha1_calculator.getDigest();
data_sha1.assign((char*) data_tmpdigest, 20);
free(data_tmpdigest);
}
// Check that received file matches announced checksum
if (data_sha1 != sha1) {
std::string data_sha1_hex = hex_encode(data_sha1);
infostream << "Client: "
<< cached_or_received_uc << " media file "
<< sha1_hex << " \"" << name << "\" "
<< "mismatches actual checksum " << data_sha1_hex
<< std::endl;
return false;
}
// Checksum is ok, try loading the file
bool success = client->loadMedia(data, name);
if (!success) {
infostream << "Client: "
<< "Failed to load " << cached_or_received << " media: "
<< sha1_hex << " \"" << name << "\""
<< std::endl;
return false;
}
verbosestream << "Client: "
<< "Loaded " << cached_or_received << " media: "
<< sha1_hex << " \"" << name << "\""
<< std::endl;
// Update cache (unless we just loaded the file from the cache)
if (!is_from_cache)
m_media_cache.update(sha1_hex, data);
return true;
}
/*
Minetest Hashset File Format
All values are stored in big-endian byte order.
[u32] signature: 'MTHS'
[u16] version: 1
For each hash in set:
[u8*20] SHA1 hash
Version changes:
1 - Initial version
*/
std::string ClientMediaDownloader::serializeRequiredHashSet()
{
std::ostringstream os(std::ios::binary);
writeU32(os, MTHASHSET_FILE_SIGNATURE); // signature
writeU16(os, 1); // version
// Write list of hashes of files that have not been
// received (found in cache) yet
for (std::map<std::string, FileStatus*>::iterator
it = m_files.begin();
it != m_files.end(); ++it) {
if (!it->second->received) {
assert(it->second->sha1.size() == 20);
os << it->second->sha1;
}
}
return os.str();
}
void ClientMediaDownloader::deSerializeHashSet(const std::string &data,
std::set<std::string> &result)
{
if (data.size() < 6 || data.size() % 20 != 6) {
throw SerializationError(
"ClientMediaDownloader::deSerializeHashSet: "
"invalid hash set file size");
}
const u8 *data_cstr = (const u8*) data.c_str();
u32 signature = readU32(&data_cstr[0]);
if (signature != MTHASHSET_FILE_SIGNATURE) {
throw SerializationError(
"ClientMediaDownloader::deSerializeHashSet: "
"invalid hash set file signature");
}
u16 version = readU16(&data_cstr[4]);
if (version != 1) {
throw SerializationError(
"ClientMediaDownloader::deSerializeHashSet: "
"unsupported hash set file version");
}
for (u32 pos = 6; pos < data.size(); pos += 20) {
result.insert(data.substr(pos, 20));
}
}