jsicontext.cpp

Open VXI. This is a open source.

VXIjsiResult JsiContext::CreateVar (const VXIchar  *name, 
				    const VXIchar  *expr)
{
  if (( name == NULL ) || ( name[0] == 0 ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  // If this is a fully qualified name, just do a SetVar( ) as that
  // handles explicitly scoped variables and this doesn't. No
  // functional effect to doing so, the only difference is that
  // CreateVar( ) masks vars of the same name from prior scopes when
  // SetVar( ) just sets the old one, having an explicit scope makes
  // that irrelevant since then JS knows exactly what to do.
  if ( wcschr (name, L'.') )
    return SetVar (name, expr);

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Evaluate the expression, need to eval before setting so we can
  // deal with things like "1; 2;" which can't be handled if we just
  // make a temporary script
  VXIjsiResult rc = VXIjsi_RESULT_SUCCESS;
  JsiProtectedJsval val (context);
  if (( expr != NULL ) && ( expr[0] != 0 ))
    rc = EvaluateScript (expr, &val);

  // Set the variable in the current scope directly, ensures we mask
  // any var of the same name from earlier scopes
  if ( rc == VXIjsi_RESULT_SUCCESS ) {
    GET_JSCHAR_FROM_VXICHAR(tmpname, tmpnamelen, name);
    if ( ! JS_DefineUCProperty (context, currentScope->GetJsobj( ), 
				tmpname, tmpnamelen, val.Get( ), NULL, NULL,
				JSPROP_ENUMERATE) )
      rc = VXIjsi_RESULT_OUT_OF_MEMORY;
  }

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Create a script variable relative to the current scope
VXIjsiResult JsiContext::CreateVar (const VXIchar  *name, 
				    const VXIValue *value)
{
  if (( name == NULL ) || ( name[0] == 0 ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  // If this is a fully qualified name, just do a SetVar( ) as that
  // handles explicitly scoped variables and this doesn't. No
  // functional effect to doing so, the only difference is that
  // CreateVar( ) masks vars of the same name from prior scopes when
  // SetVar( ) just sets the old one, having an explicit scope makes
  // that irrelevant since then JS knows exactly what to do.
  if ( wcschr (name, L'.') )
    return SetVar (name, value);

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Convert the value to a JavaScript variable
  VXIjsiResult rc = VXIjsi_RESULT_SUCCESS;
  JsiProtectedJsval val (context);
  if ( value )
    rc = VXIValueToJsval (context, value, &val);

  // Set the variable in the current scope directly, ensures we mask
  // any var of the same name from earlier scopes
  if ( rc == VXIjsi_RESULT_SUCCESS ) {
    GET_JSCHAR_FROM_VXICHAR(tmpname, tmpnamelen, name);
    if ( ! JS_DefineUCProperty (context, currentScope->GetJsobj( ), 
				tmpname, tmpnamelen, val.Get( ), NULL, NULL,
				JSPROP_ENUMERATE) )
      rc = VXIjsi_RESULT_OUT_OF_MEMORY;
  }

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Set a script variable relative to the current scope
VXIjsiResult JsiContext::SetVar (const VXIchar     *name, 
				 const VXIchar     *expr)
{
  if (( name == NULL ) || ( name[0] == 0 ) ||
      ( expr == NULL ) || ( expr[0] == 0 ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Evaluate the expression, need to eval before setting so we can
  // deal with things like "1; 2;" which can't be handled if we just
  // make a temporary script
  JsiProtectedJsval val (context);
  VXIjsiResult rc = EvaluateScript (expr, &val);

  // What we'd like to do is lookup the variable, then set it to the
  // jsval we got above. (The lookup is complex because it could be
  // a partially or fully qualified name, with potential scope
  // chain/prototype chain lookups.) However, that isn't possible in
  // SpiderMonkey. So instead we set a temporary variable in the
  // global scope, then assign the specified object to that, then
  // destroy the temporary.
  if ( rc == VXIjsi_RESULT_SUCCESS ) {
    if ( JS_DefineProperty (context, currentScope->GetJsobj( ),
			    GLOBAL_TEMP_VAR, val.Get( ), NULL, NULL, 0) ) {
      // Do the copy using a temporary script
      SBinetString script (name);
      script += L"=";
      script += GLOBAL_TEMP_VAR_W;
      rc = EvaluateScript (script.c_str( ), NULL);

      // Destroy the temporary variable
      jsval ignored = JSVAL_VOID;
      if ( ! JS_DeleteProperty2 (context, currentScope->GetJsobj( ), 
				 GLOBAL_TEMP_VAR, &ignored) )
	rc = VXIjsi_RESULT_FATAL_ERROR;
    } else {
      rc = VXIjsi_RESULT_OUT_OF_MEMORY;
    }
  }

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Set a script variable relative to the current scope
VXIjsiResult JsiContext::SetVar (const VXIchar   *name, 
				 const VXIValue  *value)
{
  if (( name == NULL ) || ( name[0] == 0 ) || ( value == NULL ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Convert the value to a JavaScript variable
  JsiProtectedJsval val (context);
  VXIjsiResult rc = VXIValueToJsval (context, value, &val);

  // What we'd like to do is lookup the variable, then set it to the
  // jsval we got above. (The lookup is complex because it could be
  // a partially or fully qualified name, with potential scope
  // chain/prototype chain lookups.) However, that isn't possible in
  // SpiderMonkey. So instead we set a temporary variable in the
  // global scope, then assign the specified object to that, then
  // destroy the temporary.
  if ( rc == VXIjsi_RESULT_SUCCESS ) {
    if ( JS_DefineProperty (context, currentScope->GetJsobj( ),
			    GLOBAL_TEMP_VAR, val.Get( ), NULL, NULL, 0) ) {
      // Do the copy using a temporary script
      SBinetString script (name);
      script += L"=";
      script += GLOBAL_TEMP_VAR_W;
      rc = EvaluateScript (script.c_str( ), NULL);

      // Destroy the temporary variable
      jsval ignored = JSVAL_VOID;
      if ( ! JS_DeleteProperty2 (context, currentScope->GetJsobj( ), 
				 GLOBAL_TEMP_VAR, &ignored) )
	rc = VXIjsi_RESULT_FATAL_ERROR;
    } else {
      rc = VXIjsi_RESULT_OUT_OF_MEMORY;
    }
  }

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Get the value of a variable
VXIjsiResult JsiContext::GetVar (const VXIchar     *name,
				 VXIValue         **value) const
{
  if (( name == NULL ) || ( name[0] == 0 ) || ( value == NULL ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  *value = NULL;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Get the variable, we need to evaluate instead of just calling
  // JS_GetUCProperty( ) in order to have it automatically look back
  // through the scope chain, as well as to permit explicit scope
  // references like "myscope.myvar"
  JsiProtectedJsval val (context);
  VXIjsiResult rc = EvaluateScript (name, &val);

  if ( rc == VXIjsi_RESULT_SUCCESS )
    rc = JsvalToVXIValue (context, val.Get( ), value);
  else if (( rc == VXIjsi_RESULT_SYNTAX_ERROR ) ||
	   ( rc == VXIjsi_RESULT_SCRIPT_EXCEPTION ))
    rc = VXIjsi_RESULT_NON_FATAL_ERROR;

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Check whether a variable is defined (not void, could be NULL)
VXIjsiResult JsiContext::CheckVar (const VXIchar   *name) const
{
  if (( name == NULL ) || ( name[0] == 0 ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Get the variable, we need to evaluate instead of just calling
  // JS_GetUCProperty( ) in order to have it automatically look back
  // through the scope chain, as well as to permit explicit scope
  // references like "myscope.myvar". We disable logging because
  // we don't want JavaScript error reports about this var being
  // undefined.
  JsiProtectedJsval val (context);
  VXIjsiResult rc = EvaluateScript (name, &val, false);

  if (( rc == VXIjsi_RESULT_SYNTAX_ERROR ) ||
      ( rc == VXIjsi_RESULT_SCRIPT_EXCEPTION ) ||
      ( rc == VXIjsi_RESULT_NON_FATAL_ERROR ) ||
      (( rc == VXIjsi_RESULT_SUCCESS ) &&
       ( JSVAL_IS_VOID (val.Get( )) )))   // JavaScript undefined
    rc = VXIjsi_RESULT_FAILURE;

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Execute a script, optionally returning any execution result
VXIjsiResult JsiContext::Eval (const VXIchar       *expr,
			       VXIValue           **result)
{
  if (( expr == NULL ) || ( expr[0] == 0 ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  if ( result )
    *result = NULL;

  // Execute the script
  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  JsiProtectedJsval val (context);
  VXIjsiResult rc = EvaluateScript (expr, &val);

  if (( result ) && ( rc == VXIjsi_RESULT_SUCCESS ) &&
      ( val.Get( ) != JSVAL_VOID ))
    rc = JsvalToVXIValue (context, val.Get( ), result);

  // Must unroot before unlocking
  val.Clear( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Push a new context onto the scope chain (add a nested scope)
VXIjsiResult JsiContext::PushScope (const VXIchar *name)
{
  if (( ! name ) || ( ! name[0] ))
    return VXIjsi_RESULT_INVALID_ARGUMENT;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  // Create an object for the scope, the current scope is its parent
  VXIjsiResult rc = VXIjsi_RESULT_SUCCESS;
  JSObject *scope = JS_NewObject (context, &SCOPE_CLASS, NULL, 
				  currentScope->GetJsobj( ));
  if ( ! scope ) {
    rc = VXIjsi_RESULT_OUT_OF_MEMORY;
  } else {
    Diag (SBJSI_LOG_SCOPE, L"JsiContext::PushScope", 
	  L"scope %s (0x%p), context 0x%p", name, scope, context);

    // The scope chain node object locks it to protect this from
    // garbage collection in case someone (possibly a malicious
    // script) destroys the data member pointing at this in the global
    // scope
    JsiScopeChainNode *newScope = 
      new JsiScopeChainNode (context, currentScope, name);
    if ( newScope ) {
      rc = newScope->Create (scope);
      if (( rc == VXIjsi_RESULT_SUCCESS ) &&
	  ( ! JS_SetPrivate (context, scope, newScope) ))
	rc = VXIjsi_RESULT_FATAL_ERROR;
    } else {
      rc = VXIjsi_RESULT_OUT_OF_MEMORY;
    }

    // Set this scope as a property of the parent scope
    if ( rc == VXIjsi_RESULT_SUCCESS ) {
      GET_JSCHAR_FROM_VXICHAR(tmpname, tmpnamelen, name);
      if ( JS_DefineUCProperty (context, currentScope->GetJsobj( ), tmpname,
				tmpnamelen, newScope->GetJsval( ), NULL, NULL, 
				JSPROP_ENUMERATE) ) {
	// Add it to the scope chain and set it as the current scope
	currentScope->SetChild (newScope);
	currentScope = newScope;
      } else {
	rc = VXIjsi_RESULT_FATAL_ERROR;
      }
    }
  }

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Pop a context from the scope chain (remove a nested scope)
VXIjsiResult JsiContext::PopScope( )
{
  // Don't pop up past the global scope
  if ( currentScope == scopeChain )
    return VXIjsi_RESULT_NON_FATAL_ERROR;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  Diag (SBJSI_LOG_SCOPE, L"JsiContext::PopScope", 
	L"scope %s (0x%p), context 0x%p", 
	currentScope->GetName( ).c_str( ), currentScope->GetJsobj( ), context);
  
  // Revert to the parent scope
  JsiScopeChainNode *oldScope = currentScope;
  currentScope = currentScope->GetParent( );
  currentScope->SetChild (NULL);

  // Release the old scope variable within the parent scope to permit
  // it to be garbage collected
  VXIjsiResult rc = VXIjsi_RESULT_SUCCESS;
  jsval rval;
  GET_JSCHAR_FROM_VXICHAR(tmpname, tmpnamelen, oldScope->GetName( ).c_str( ));
  if ( ! JS_DeleteUCProperty2 (context, currentScope->GetJsobj( ), tmpname,
			       tmpnamelen, &rval) )
    rc = VXIjsi_RESULT_FATAL_ERROR;

  // Now finish releasing the old scope, the actual wrapper object is
  // freed by the scope finalize method when garbage collection occurs
  rc = oldScope->Release( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Reset the scope chain to the global scope (pop all nested scopes)
VXIjsiResult JsiContext::ClearScopes( )
{
  // See if there is anything to do
  if ( currentScope == scopeChain )
    return VXIjsi_RESULT_SUCCESS;

  if ( AccessBegin( ) == false )
    return VXIjsi_RESULT_SYSTEM_ERROR;

  Diag (SBJSI_LOG_SCOPE, L"JsiContext::ClearScopes", L"context 0x%p", 
	context);

  // Revert to the global scope
  JsiScopeChainNode *oldScope = scopeChain->GetChild( );
  currentScope = scopeChain;
  currentScope->SetChild (NULL);

  // Release the old child scope variable within the global scope to
  // permit it and all its descendants to be garbage collected
  VXIjsiResult rc = VXIjsi_RESULT_SUCCESS;
  jsval rval;
  GET_JSCHAR_FROM_VXICHAR(tmpname, tmpnamelen, oldScope->GetName( ).c_str( ));
  if ( ! JS_DeleteUCProperty2 (context, currentScope->GetJsobj( ), tmpname,
			       tmpnamelen, &rval) )
    rc = VXIjsi_RESULT_FATAL_ERROR;
  
  // Now finish releasing the old scope, the actual wrapper object is
  // freed by the scope finalize method when garbage collection occurs
  rc = oldScope->Release( );

  if ( AccessEnd( ) == false )
    rc = VXIjsi_RESULT_SYSTEM_ERROR;

  return rc;
}


// Script evaluation
VXIjsiResult JsiContext::EvaluateScript (const VXIchar *script, 
					 JsiProtectedJsval *retval,
					 bool loggingEnabled) const