private CSharpName GetEarlyExitNameIfRequired(DoBlock doBlock, ScopeAccessInformation scopeAccessInformation)
{
if (doBlock == null)
{
throw new ArgumentNullException("doBlock");
}
if (scopeAccessInformation == null)
{
throw new ArgumentNullException("scopeAccessInformation");
}
if (!doBlock.SupportsExit || !doBlock.ContainsLoopThatContainsMismatchedExitThatMustBeHandledAtThisLevel())
{
return(null);
}
return(_tempNameGenerator(new CSharpName("exitDo"), scopeAccessInformation));
}
public TranslationResult Translate(DoBlock doBlock, ScopeAccessInformation scopeAccessInformation, int indentationDepth)
{
if (doBlock == null)
{
throw new ArgumentNullException("doBlock");
}
if (scopeAccessInformation == null)
{
throw new ArgumentNullException("scopeAccessInformation");
}
if (indentationDepth < 0)
{
throw new ArgumentOutOfRangeException("indentationDepth", "must be zero or greater");
}
if ((doBlock.ConditionIfAny == null) && !doBlock.Statements.Any())
{
_logger.Warning("Infinite DO/WHILE loop at line " + (doBlock.LineIndexOfStartOfConstruct + 1));
return(TranslationResult.Empty.Add(new TranslatedStatement(
"while (true) { }",
indentationDepth,
doBlock.LineIndexOfStartOfConstruct
)));
}
var earlyExitNameIfAny = GetEarlyExitNameIfRequired(doBlock, scopeAccessInformation);
var loopStatementsTranslationResult = Translate(
doBlock.Statements.ToNonNullImmutableList(),
scopeAccessInformation.SetParent(doBlock),
doBlock.SupportsExit,
earlyExitNameIfAny,
indentationDepth + 1
);
TranslatedStatementContentDetails whileConditionExpressionContentIfAny;
if (doBlock.ConditionIfAny == null)
{
whileConditionExpressionContentIfAny = null;
}
else
{
whileConditionExpressionContentIfAny = _statementTranslator.Translate(
doBlock.ConditionIfAny,
scopeAccessInformation,
ExpressionReturnTypeOptions.Boolean,
_logger.Warning
);
if (!doBlock.IsDoWhileCondition)
{
// C# doesn't support "DO UNTIL x" but it's equivalent to "DO WHILE !x"
whileConditionExpressionContentIfAny = new TranslatedStatementContentDetails(
"!" + whileConditionExpressionContentIfAny.TranslatedContent,
whileConditionExpressionContentIfAny.VariablesAccessed
);
}
if (scopeAccessInformation.ErrorRegistrationTokenIfAny != null)
{
// Ensure that the frankly ludicrous VBScript error-handling is applied where required. As the IProvideVBScriptCompatFunctionality's IF method
// signature describes, if an error occurs in retrieving the value, it will be evaluated as true. So, given a function
//
// FUNCTION GetValue()
// Err.Raise vbObjectError, "Test", "Test"
// END FUNCTION
//
// both of the following loops will be entered:
//
// ON ERROR RESUME NEXT
// DO WHILE GetValue()
// WScript.Echo "True"
// EXIT DO
// LOOP
//
// ON ERROR RESUME NEXT
// DO UNTIL GetValue()
// WScript.Echo "True"
// EXIT DO
// LOOP
//
// This is why an additional IF call must be wrapped around the IF above - since the negation of a DO UNTIL (as opposed to a DO WHILE) loop
// must be within the outer, error-handling IF call. (A simpler example of the above is to replace the GetValue() call with 1/0, which will
// result in a "Division by zero" error if ON ERROR RESUME NEXT is not present, but which will result in both of the above loops being
// entered if it IS present).
whileConditionExpressionContentIfAny = new TranslatedStatementContentDetails(
string.Format(
"{0}.IF(() => {1}, {2})",
_supportRefName.Name,
whileConditionExpressionContentIfAny.TranslatedContent,
scopeAccessInformation.ErrorRegistrationTokenIfAny.Name
),
whileConditionExpressionContentIfAny.VariablesAccessed
);
}
}
var translationResult = TranslationResult.Empty;
if (whileConditionExpressionContentIfAny != null)
{
translationResult = translationResult.AddUndeclaredVariables(
whileConditionExpressionContentIfAny.GetUndeclaredVariablesAccessed(scopeAccessInformation, _nameRewriter)
);
}
if (whileConditionExpressionContentIfAny == null)
{
translationResult = translationResult.Add(new TranslatedStatement(
"while (true)",
indentationDepth,
doBlock.LineIndexOfStartOfConstruct
));
}
else if (doBlock.IsPreCondition)
{
translationResult = translationResult.Add(new TranslatedStatement(
"while (" + whileConditionExpressionContentIfAny.TranslatedContent + ")",
indentationDepth,
doBlock.LineIndexOfStartOfConstruct
));
}
else
{
translationResult = translationResult.Add(new TranslatedStatement(
"do",
indentationDepth,
doBlock.LineIndexOfStartOfConstruct
));
}
translationResult = translationResult.Add(new TranslatedStatement("{", indentationDepth, doBlock.LineIndexOfStartOfConstruct));
if (earlyExitNameIfAny != null)
{
translationResult = translationResult.Add(new TranslatedStatement(
string.Format("var {0} = false;", earlyExitNameIfAny.Name),
indentationDepth + 1,
doBlock.LineIndexOfStartOfConstruct
));
}
translationResult = translationResult.Add(loopStatementsTranslationResult);
var lineIndexForClosingCode = loopStatementsTranslationResult.TranslatedStatements.Any()
? loopStatementsTranslationResult.TranslatedStatements.Last().LineIndexOfStatementStartInSource
: doBlock.LineIndexOfStartOfConstruct;
if ((whileConditionExpressionContentIfAny == null) || doBlock.IsPreCondition)
{
translationResult = translationResult.Add(new TranslatedStatement("}", indentationDepth, lineIndexForClosingCode));
}
else
{
translationResult = translationResult.Add(new TranslatedStatement(
"} while (" + whileConditionExpressionContentIfAny.TranslatedContent + ");",
indentationDepth,
doBlock.ConditionIfAny.Tokens.First().LineIndex
));
}
var earlyExitFlagNamesToCheck = scopeAccessInformation.StructureExitPoints
.Where(e => e.ExitEarlyBooleanNameIfAny != null)
.Select(e => e.ExitEarlyBooleanNameIfAny.Name);
if (earlyExitFlagNamesToCheck.Any())
{
// These lines do not directly have equivalents in the source, so just take the line index of the previous line that was generated
// by the above code
var lineIndexForEarlyExitCode = translationResult.TranslatedStatements.Last().LineIndexOfStatementStartInSource;
// Perform early-exit checks for any scopeAccessInformation.StructureExitPoints - if this is DO..LOOP loop inside a FOR loop and an
// EXIT FOR was encountered within the DO..LOOP that must refer to the containing FOR, then the DO..LOOP will have been broken out
// of, but also a flag set that means that we must break further to get out of the FOR loop.
translationResult = translationResult
.Add(new TranslatedStatement(
"if (" + string.Join(" || ", earlyExitFlagNamesToCheck) + ")",
indentationDepth,
lineIndexForEarlyExitCode
))
.Add(new TranslatedStatement(
"break;",
indentationDepth + 1,
lineIndexForEarlyExitCode
));
}
return(translationResult);
}
