DebuggingServer.h

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/* Copyright (C) 2013 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_DEBUGGINGSERVER
#define INCLUDED_DEBUGGINGSERVER

#include "third_party/mongoose/mongoose.h"
#include "ScriptInterface.h"

#include "lib/external_libraries/libsdl.h"

class CBreakPoint;
class CThreadDebugger;

enum DBGCMD { DBG_CMD_NONE=0, DBG_CMD_CONTINUE, DBG_CMD_SINGLESTEP, DBG_CMD_STEPINTO, DBG_CMD_STEPOUT };
enum STACK_INFO { STACK_INFO_LOCALS=0, STACK_INFO_THIS, STACK_INFO_GLOBALOBJECT };

class CDebuggingServer
{
public:
    CDebuggingServer();
    ~CDebuggingServer();
    
    /** @brief Register a new ScriptInerface for debugging the scripts it executes
     *
     * @param name A name for the ScriptInterface (will be sent to the debugging client an probably displayed to the user)
     * @param pScriptInterface A pointer to the ScriptInterface. This pointer must stay valid until UnRegisterScriptInterface ist called!
     */
    void RegisterScriptinterface(std::string name, ScriptInterface* pScriptInterface);
    
    /** @brief Unregister a ScriptInerface that was previously registered using RegisterScriptinterface. 
     *
     * @param pScriptInterface A pointer to the ScriptInterface
     */
    void UnRegisterScriptinterface(ScriptInterface* pScriptInterface);

    
    // Mongoose callback when request comes from a client 
    void* MgDebuggingServerCallback(mg_event event, struct mg_connection *conn, const struct mg_request_info *request_info);    
    
    /** @brief Aquire exclusive read and write access to the list of breakpoints.
     *
     * @param breakPoints A pointer to the list storing all breakpoints.
     *
     * @return  A number you need to pass to ReleaseBreakPointAccess().
     *
     * Make sure to call ReleaseBreakPointAccess after you don't need access any longer.
     * Using this function you get exclusive access and other threads won't be able to access the breakpoints until you call ReleaseBreakPointAccess!
     */
    double AquireBreakPointAccess(std::list<CBreakPoint>** breakPoints);
    
    /** @brief See AquireBreakPointAccess(). You must not access the pointer returend by AquireBreakPointAccess() any longer after you call this function.
     *  
     * @param breakPointsLockID The number you got when aquiring the access. It's used to make sure that this function never gets
     *          used by the wrong thread.        
     */ 
    void ReleaseBreakPointAccess(double breakPointsLockID);
    
    
    /// Called from multiple Mongoose threads and multiple ScriptInterface threads
    bool GetBreakRequestedByThread();
    bool GetBreakRequestedByUser();
    // Should other threads be stopped as soon as possible after a breakpoint is triggered in a thread
    bool GetSettingSimultaneousThreadBreak();
    // Should the debugger break on any JS-Exception? If set to false, it will only break when the exceptions text is "Breakpoint".
    bool GetSettingBreakOnException();
    void SetBreakRequestedByThread(bool Enabled);
    void SetBreakRequestedByUser(bool Enabled);
    
private:
    static const char* header400;

    /// Webserver helper function (can be called by multiple mongooser threads)
    bool GetWebArgs(struct mg_connection *conn, const struct mg_request_info* request_info, std::string argName, uint& arg);
    bool GetWebArgs(struct mg_connection *conn, const struct mg_request_info* request_info, std::string argName, std::string& arg);
    
    /// Functions that are made available via http (can be called by multiple mongoose threads)
    void GetThreadDebuggerStatus(std::stringstream& response);
    void ToggleBreakPoint(std::string filename, uint line);
    void GetAllCallstacks(std::stringstream& response);
    void GetStackFrameData(std::stringstream& response, uint nestingLevel, uint threadDebuggerID, STACK_INFO stackInfoKind);
    bool SetNextDbgCmd(uint threadDebuggerID, DBGCMD dbgCmd);
    void SetSettingSimultaneousThreadBreak(bool Enabled);
    void SetSettingBreakOnException(bool Enabled);
    
    /** @brief Returns a list of the full vfs paths to all files with the extension .js found in the vfs root
     * 
     *  @param response This will contain the list as JSON array.
     */
    void EnumVfsJSFiles(std::stringstream& response);
    
    /** @brief Get the content of a .js file loaded into vfs
     *
     * @param filename A full vfs path (as returned by EnumVfsJSFiles).
     * @param response This will contain the contents of the requested file.
     */
    void GetFile(std::string filename, std::stringstream& response);
    
    /// Shared between multiple mongoose threads
    

    bool m_SettingSimultaneousThreadBreak;
    bool m_SettingBreakOnException;
    
    /// Shared between multiple scriptinterface threads
    uint m_LastThreadDebuggerID;
    
    /// Shared between multiple scriptinerface threads and multiple mongoose threads
    std::list<CThreadDebugger*> m_ThreadDebuggers;
    
    // The CThreadDebuggers will check this value and break the thread if it's true.
    // This only works for JS code, so C++ code will not break until it executes JS-code again.
    bool m_BreakRequestedByThread;
    bool m_BreakRequestedByUser;
    
    // The breakpoint is uniquely identified using filename an line-number.
    // Since the filename is the whole vfs path it should really be unique.
    std::list<CBreakPoint> m_BreakPoints;
    
    /// Used for controlling access to m_BreakPoints
    SDL_sem* m_BreakPointsSem;
    double m_BreakPointsLockID;
    
    /// Mutexes used to ensure thread-safety. Currently we just use one Mutex (m_Mutex) and if we detect possible sources
    /// of deadlocks, we use the second mutex for some members to avoid it.
    CMutex m_Mutex;
    CMutex m_Mutex1;
    
    /// Not important for this class' thread-safety
    void EnableHTTP();
    mg_context* m_MgContext;
};

extern CDebuggingServer* g_DebuggingServer;


#endif // INCLUDED_DEBUGGINGSERVER