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Improving cross-platform compatibility of webdriver-server C++ code.
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This commit makes the common webdriver-server C++ code more easily
cross-platform. It does this mainly by removing use of std::tr1::regex,
which has issues compiling under gcc. In its place, we now use a custom
URL matching algorithm for matching URLs in the WebDriver JSON Wire
Protocol. While this matching algorithm may be a source of future errors,
a nice side effect of it is a 3% performance increase in server execution
times over using regular expressions.

Additionally, this commit includes an alias for snprintf, which throws
buffer overrun warnings when used with Visual Studio. It also contains
some header #include rearranging and linting of the C++ code.
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@jimevans
jimevans committed Sep 11, 2014
1 parent 03bd468 commit fe013b5
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Showing 8 changed files with 264 additions and 88 deletions.
2 changes: 0 additions & 2 deletions cpp/webdriver-server/precompile.h
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,6 @@
#endif

#define WINDOWS

#include <windows.h>
#else
// TODO(JimEvans): Add non-Windows includes here
#endif
Expand Down
135 changes: 60 additions & 75 deletions cpp/webdriver-server/server.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -11,14 +11,33 @@
// See the License for the specific language governing permissions and
// limitations under the License.

#include <regex>
#include "server.h"
#include <cstdio>
#include <cstring>
#include <sstream>
#include "session.h"
#include "uri_info.h"
#include "logging.h"

#define SERVER_DEFAULT_PAGE "<html><head><title>WebDriver</title></head><body><p id='main'>This is the initial start page for the WebDriver server.</p></body></html>"
#define HTML_CONTENT_TYPE "text/html"
#define JSON_CONTENT_TYPE "application/json"

#if defined(WINDOWS)
#include <cstdarg>
inline int wd_snprintf(char* str, size_t size, const char* format, ...) {
va_list args;
va_start(args, format);
int count = _vscprintf(format, args);
if (str != NULL && size > 0) {
count = _vsnprintf_s(str, size, _TRUNCATE, format, args);
}
va_end(args);
return count;
}
#define snprintf wd_snprintf
#endif

namespace webdriver {

Server::Server(const int port) {
Expand Down Expand Up @@ -50,7 +69,8 @@ void Server::Initialize(const int port,
const std::string& log_file) {
LOG::Level(log_level);
LOG::File(log_file);
LOG(INFO) << "Starting WebDriver server on port: '" << port << "' on host: '" << host << "'";
LOG(INFO) << "Starting WebDriver server on port: '"
<< port << "' on host: '" << host << "'";
this->port_ = port;
this->host_ = host;
this->PopulateCommandRepository();
Expand All @@ -74,19 +94,20 @@ bool Server::Start() {
// empty string.
port_format_string = "%s%d";
}
int formatted_string_size = _scprintf(port_format_string.c_str(),
this->host_.c_str(),
this->port_);
char* listening_ports_buffer = new char[formatted_string_size + 1];
_snprintf_s(listening_ports_buffer,
formatted_string_size + 1,
formatted_string_size,
port_format_string.c_str(),
this->host_.c_str(),
this->port_);
int formatted_string_size = snprintf(NULL,
0,
port_format_string.c_str(),
this->host_.c_str(),
this->port_) + 1;
char* listening_ports_buffer = new char[formatted_string_size];
snprintf(listening_ports_buffer,
formatted_string_size,
port_format_string.c_str(),
this->host_.c_str(),
this->port_);

std::string acl = "-0.0.0.0/0,+127.0.0.1";
LOG(DEBUG) << "Mongoose ACL is " << acl;
LOG(DEBUG) << "Civetweb ACL is " << acl;

const char* options[] = { "listening_ports", listening_ports_buffer,
"access_control_list", acl.c_str(),
Expand All @@ -96,7 +117,7 @@ bool Server::Start() {
callbacks.begin_request = &OnNewHttpRequest;
context_ = mg_start(&callbacks, this, options);
if (context_ == NULL) {
LOG(WARN) << "Failed to start Mongoose";
LOG(WARN) << "Failed to start Civetweb";
return false;
}
return true;
Expand All @@ -114,7 +135,7 @@ int Server::ProcessRequest(struct mg_connection* conn,
const struct mg_request_info* request_info) {
LOG(TRACE) << "Entering Server::ProcessRequest";

int http_response_code = NULL;
int http_response_code = 0;
std::string http_verb = request_info->request_method;
std::string request_body = "{}";
if (http_verb == "POST") {
Expand Down Expand Up @@ -154,7 +175,12 @@ int Server::ProcessRequest(struct mg_connection* conn,
void Server::AddCommand(const std::string& url,
const std::string& http_verb,
const std::string& command_name) {
this->commands_[url][http_verb] = command_name;
if (this->commands_.find(url) == this->commands_.end()) {
this->commands_[url] = std::tr1::shared_ptr<UriInfo>(
new UriInfo(url, http_verb, command_name));
} else {
this->commands_[url]->AddHttpVerb(http_verb, command_name);
}
}

void Server::ShutDownSession(const std::string& session_id) {
Expand Down Expand Up @@ -242,7 +268,7 @@ std::string Server::DispatchCommand(const std::string& uri,
// not by the session.
serialized_response = this->ListSessions();
} else {
SessionHandle session_handle = NULL;
SessionHandle session_handle;
if (command != webdriver::CommandType::NewSession &&
!this->LookupSession(session_id, &session_handle)) {
if (command == webdriver::CommandType::Quit) {
Expand Down Expand Up @@ -297,7 +323,9 @@ std::string Server::ListSessions() {

// Manually construct the serialized command for getting
// session capabilities.
std::string get_caps_command = "{ \"name\" : \"" + webdriver::CommandType::GetSessionCapabilities + "\"" +
std::string get_caps_command = "{ \"name\" : \"" +
webdriver::CommandType::GetSessionCapabilities
+ "\"" +
", \"locator\" : {}, \"parameters\" : {} }";

Json::Value sessions(Json::arrayValue);
Expand Down Expand Up @@ -513,37 +541,32 @@ std::string Server::LookupCommand(const std::string& uri,
LOG(TRACE) << "Entering Server::LookupCommand";

std::string value = webdriver::CommandType::NoCommand;
std::vector<std::string> url_fragments;
UriInfo::ParseUri(uri, &url_fragments, NULL);
UrlMap::const_iterator it = this->commands_.begin();
for (; it != this->commands_.end(); ++it) {
std::string url_candidate = it->first;
std::vector<std::string> locator_param_names;
std::vector<std::string> locator_param_values;
if (this->IsCommandMatch(uri, url_candidate, &locator_param_names, &locator_param_values)) {
VerbMap::const_iterator verb_iterator = it->second.find(http_verb);
if (verb_iterator != it->second.end()) {
value = verb_iterator->second;
std::string param = this->ConstructLocatorParameterJson(locator_param_names,
locator_param_values,
session_id);
if (it->second->IsUriMatch(url_fragments,
&locator_param_names,
&locator_param_values)) {
if (it->second->HasHttpVerb(http_verb, &value)) {
std::string param = this->ConstructLocatorParameterJson(
locator_param_names, locator_param_values, session_id);
locator->append(param);
break;
} else {
verb_iterator = it->second.begin();
for (; verb_iterator != it->second.end(); ++verb_iterator) {
if (locator->size() != 0) {
locator->append(",");
}
locator->append(verb_iterator->first);
}
locator->append(it->second->GetSupportedVerbs());
}
break;
}
}
return value;
}

std::string Server::ConstructLocatorParameterJson(std::vector<std::string> locator_param_names,
std::vector<std::string> locator_param_values,
std::string* session_id) {
std::string Server::ConstructLocatorParameterJson(
std::vector<std::string> locator_param_names,
std::vector<std::string> locator_param_values,
std::string* session_id) {
std::string param = "{";
size_t param_count = locator_param_names.size();
for (unsigned int i = 0; i < param_count; i++) {
Expand All @@ -565,44 +588,6 @@ std::string Server::ConstructLocatorParameterJson(std::vector<std::string> locat
return param;
}

bool Server::IsCommandMatch(const std::string& uri,
const std::string& url_template,
std::vector<std::string>* locator_param_names,
std::vector<std::string>* locator_param_values) {
std::string url_match_regex = url_template;
size_t param_start_pos = url_match_regex.find_first_of(":");
while (param_start_pos != std::string::npos) {
size_t param_len = std::string::npos;
size_t param_end_pos = url_match_regex.find_first_of("/", param_start_pos);
if (param_end_pos != std::string::npos) {
param_len = param_end_pos - param_start_pos;
}

// Skip the colon
std::string param_name = url_match_regex.substr(param_start_pos + 1,
param_len - 1);
locator_param_names->push_back(param_name);
if (param_name == "sessionid" || param_name == "id") {
url_match_regex.replace(param_start_pos, param_len, "([0-9a-fA-F-]+)");
} else {
url_match_regex.replace(param_start_pos, param_len, "([^/]+)");
}
param_start_pos = url_match_regex.find_first_of(":");
}

std::tr1::regex matcher("^" + url_match_regex + "$");
std::tr1::match_results<std::string::const_iterator> matches;
if (std::tr1::regex_search(uri, matches, matcher)) {
size_t param_count = locator_param_names->size();
for (unsigned int i = 0; i < param_count; i++) {
std::string locator_param_value = matches[i + 1].str();
locator_param_values->push_back(locator_param_value);
}
return true;
}
return false;
}

void Server::PopulateCommandRepository() {
LOG(TRACE) << "Entering Server::PopulateCommandRepository";

Expand Down
20 changes: 12 additions & 8 deletions cpp/webdriver-server/server.h
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Original file line number Diff line number Diff line change
Expand Up @@ -17,16 +17,25 @@
#ifndef WEBDRIVER_SERVER_SERVER_H_
#define WEBDRIVER_SERVER_SERVER_H_

#include <vector>
#include <map>
#include <string>
#include <vector>
#if defined(_WIN32)
#include <memory>
#else
#include <tr1/memory>
#endif
#include "civetweb.h"
#include "command_types.h"
#include "response.h"
#include "session.h"

namespace webdriver {

class UriInfo;
class Session;

typedef std::tr1::shared_ptr<Session> SessionHandle;

class Server {
public:
explicit Server(const int port);
Expand Down Expand Up @@ -57,8 +66,7 @@ class Server {

private:
typedef std::map<std::string, SessionHandle> SessionMap;
typedef std::map<std::string, std::string> VerbMap;
typedef std::map<std::string, VerbMap> UrlMap;
typedef std::map<std::string, std::tr1::shared_ptr<UriInfo> > UrlMap;

void Initialize(const int port,
const std::string& host,
Expand All @@ -82,10 +90,6 @@ class Server {
const struct mg_request_info* request_info,
const std::string& serialized_response);
void PopulateCommandRepository(void);
bool IsCommandMatch(const std::string& uri,
const std::string& url_template,
std::vector<std::string>* locator_param_names,
std::vector<std::string>* locator_param_values);
std::string ConstructLocatorParameterJson(std::vector<std::string> locator_param_names,
std::vector<std::string> locator_param_values,
std::string* session_id);
Expand Down
3 changes: 0 additions & 3 deletions cpp/webdriver-server/session.h
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,6 @@
#ifndef WEBDRIVER_SERVER_SESSION_H_
#define WEBDRIVER_SERVER_SESSION_H_

#include <memory>
#include <string>

namespace webdriver {
Expand All @@ -44,8 +43,6 @@ class Session {
DISALLOW_COPY_AND_ASSIGN(Session);
};

typedef std::tr1::shared_ptr<Session> SessionHandle;

} // namespace webdriver

#endif // WEBDRIVER_SERVER_SESSION_H_
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