public static IEnumerable <ICSSFragment> ParseIntoStructuredData(
IEnumerable <CategorisedCharacterString> segments,
CommentHandlingOptions commentHandling = CommentHandlingOptions.Exclude)
{
if (segments == null)
{
throw new ArgumentNullException("segments");
}
if (!Enum.IsDefined(typeof(CommentHandlingOptions), commentHandling))
{
throw new ArgumentOutOfRangeException("commentHandling");
}
var segmentEnumerator = segments.GetEnumerator();
var parsedData = ParseIntoStructuredData(segmentEnumerator, new Selector.SelectorSet[0], 0, commentHandling);
while (segmentEnumerator.MoveNext())
{
var segment = segmentEnumerator.Current;
if ((segment.CharacterCategorisation != CharacterCategorisationOptions.Comment) &&
(segment.CharacterCategorisation != CharacterCategorisationOptions.Whitespace))
{
var lastFragment = parsedData.Item1.LastOrDefault();
var lastFragmentLineIndex = (lastFragment == null) ? 0 : lastFragment.SourceLineIndex;
throw new ArgumentException("Encountered unparsable data, this indicates content (after line " + (lastFragmentLineIndex + 1) + ")");
}
}
return(parsedData.Item1);
}
/// <summary>
/// This returns the parsed fragments and the number of lines that were processed from the source in doing so
/// </summary>
private static Tuple <IEnumerable <ICSSFragment>, int> ParseIntoStructuredData(
IEnumerator <CategorisedCharacterString> segmentEnumerator,
IEnumerable <Selector.SelectorSet> parentSelectors,
int sourceLineIndex,
CommentHandlingOptions commentHandling)
{
if (segmentEnumerator == null)
{
throw new ArgumentNullException("segmentEnumerator");
}
if (parentSelectors == null)
{
throw new ArgumentNullException("parentSelectors");
}
if (sourceLineIndex < 0)
{
throw new ArgumentNullException("sourceLineIndex", "must be zero or greater");
}
if (!Enum.IsDefined(typeof(CommentHandlingOptions), commentHandling))
{
throw new ArgumentOutOfRangeException("commentHandling");
}
var startingSourceLineIndex = sourceLineIndex;
var fragments = new List <ICSSFragment>();
var selectorOrStyleContentBuffer = new StringBuilder();
var selectorOrStyleStartSourceLineIndex = -1;
StylePropertyName lastStylePropertyName = null;
var stylePropertyValueBuffer = new PropertyValueBuffer();
while (segmentEnumerator.MoveNext())
{
var segment = segmentEnumerator.Current;
if (segment == null)
{
throw new ArgumentException("Null reference encountered in segments set");
}
switch (segment.CharacterCategorisation)
{
case CharacterCategorisationOptions.Comment:
if (commentHandling == CommentHandlingOptions.Include)
{
fragments.Add(new Comment(segment.Value, sourceLineIndex));
}
sourceLineIndex += GetNumberOfLineReturnsFromContentIfAny(segment.Value);
continue;
case CharacterCategorisationOptions.Whitespace:
sourceLineIndex += GetNumberOfLineReturnsFromContentIfAny(segment.Value);
if (selectorOrStyleContentBuffer.Length > 0)
{
selectorOrStyleContentBuffer.Append(" ");
}
continue;
case CharacterCategorisationOptions.SelectorOrStyleProperty:
if (selectorOrStyleContentBuffer.Length == 0)
{
selectorOrStyleStartSourceLineIndex = sourceLineIndex;
}
selectorOrStyleContentBuffer.Append(segment.Value);
// If we were building up content for a StylePropertyValue then encountering other content means that the value must have terminated
// (for valid CSS it should be only a semicolon or close brace that terminates a value but we're not concerned about invalid CSS here)
if (stylePropertyValueBuffer.HasContent)
{
fragments.Add(stylePropertyValueBuffer.ExtractCombinedContentAndClear());
}
continue;
case CharacterCategorisationOptions.OpenBrace:
if (selectorOrStyleContentBuffer.Length == 0)
{
throw new ArgumentException("Encountered OpenBrace with no preceding selector at line " + (sourceLineIndex + 1));
}
// If we were building up content for a StylePropertyValue then encountering other content means that the value must have terminated
// (for valid CSS it should be only a semicolon or close brace that terminates a value but we're not concerned about invalid CSS here)
if (stylePropertyValueBuffer.HasContent)
{
fragments.Add(stylePropertyValueBuffer.ExtractCombinedContentAndClear());
}
var selectors = GetSelectorSet(selectorOrStyleContentBuffer.ToString());
var parsedNestedContentDetails = ParseIntoStructuredData(segmentEnumerator, parentSelectors.Concat(new[] { selectors }), sourceLineIndex, commentHandling);
if (selectors.First().Value.StartsWith("@media", StringComparison.InvariantCultureIgnoreCase))
{
fragments.Add(new MediaQuery(
selectors,
parentSelectors,
selectorOrStyleStartSourceLineIndex,
parsedNestedContentDetails.Item1 // Item1 are the processed fragments (Item2 is the number of lines processed to extract those fragments)
));
}
else
{
fragments.Add(new Selector(
selectors,
parentSelectors,
selectorOrStyleStartSourceLineIndex,
parsedNestedContentDetails.Item1 // Item1 are the processed fragments (Item2 is the number of lines processed to extract those fragments)
));
}
sourceLineIndex += parsedNestedContentDetails.Item2; // Increase sourceLineIndex by the number of lines that the recursive call processed
selectorOrStyleContentBuffer.Clear();
continue;
case CharacterCategorisationOptions.CloseBrace:
// If we were building up content for a StylePropertyValue then encountering other content means that the value must have terminated
// (for valid CSS it should be only a semicolon or close brace that terminates a value but we're not concerned about invalid CSS here)
if (stylePropertyValueBuffer.HasContent)
{
fragments.Add(stylePropertyValueBuffer.ExtractCombinedContentAndClear());
}
if (selectorOrStyleContentBuffer.Length > 0)
{
fragments.Add(new StylePropertyName(
selectorOrStyleContentBuffer.ToString(),
selectorOrStyleStartSourceLineIndex
));
}
return(Tuple.Create <IEnumerable <ICSSFragment>, int>(fragments, sourceLineIndex - startingSourceLineIndex));
case CharacterCategorisationOptions.StylePropertyColon:
case CharacterCategorisationOptions.SemiColon:
// If we were building up content for a StylePropertyValue then encountering other content means that the value must have terminated
// (for valid CSS it should be only a semicolon or close brace that terminates a value but we're not concerned about invalid CSS here)
if (stylePropertyValueBuffer.HasContent)
{
fragments.Add(stylePropertyValueBuffer.ExtractCombinedContentAndClear());
}
if (selectorOrStyleContentBuffer.Length > 0)
{
var selectorOrStyleContent = selectorOrStyleContentBuffer.ToString();
if (selectorOrStyleContent.StartsWith("@import", StringComparison.InvariantCultureIgnoreCase))
{
fragments.Add(new Import(
selectorOrStyleContent.Substring("@import".Length).Trim(),
sourceLineIndex
));
selectorOrStyleContentBuffer.Clear();
continue;
}
// Note: The SemiColon case here probably suggests invalid content, it should only follow a Value segment (ignoring
// Comments and WhiteSpace), so if there is anything in the selectorOrStyleContentBuffer before the SemiColon then
// it's probably not correct (but we're not validating for that here, we just don't want to throw anything away!)
lastStylePropertyName = new StylePropertyName(
selectorOrStyleContentBuffer.ToString(),
selectorOrStyleStartSourceLineIndex
);
fragments.Add(lastStylePropertyName);
selectorOrStyleContentBuffer.Clear();
}
continue;
case CharacterCategorisationOptions.Value:
if (selectorOrStyleContentBuffer.Length > 0)
{
var selectorOrStyleContent = selectorOrStyleContentBuffer.ToString();
if (selectorOrStyleContent.StartsWith("@import", StringComparison.InvariantCultureIgnoreCase))
{
selectorOrStyleContentBuffer.Append(segment.Value);
continue;
}
// This is presumably an error condition, there should be a colon between SelectorOrStyleProperty content and
// Value content, but we're not validating here so just lump it all together
lastStylePropertyName = new StylePropertyName(
selectorOrStyleContentBuffer.ToString(),
selectorOrStyleStartSourceLineIndex
);
fragments.Add(lastStylePropertyName);
selectorOrStyleContentBuffer.Clear();
}
if (lastStylePropertyName == null)
{
throw new Exception("Invalid content, orphan style property value encountered");
}
stylePropertyValueBuffer.Add(new StylePropertyValue(
lastStylePropertyName,
new[] { segment.Value },
selectorOrStyleStartSourceLineIndex
));
continue;
default:
throw new ArgumentException("Unsupported CharacterCategorisationOptions value: " + segment.CharacterCategorisation);
}
}
// If we have any content in the selectorOrStyleContentBuffer and we're hitting a CloseBrace then it's probably invalid content,
// but just stash it away and move on! (The purpose of this work isn't to get too nuts about invalid CSS).
if (selectorOrStyleContentBuffer.Length > 0)
{
var selectors = GetSelectorSet(selectorOrStyleContentBuffer.ToString());
if (selectors.First().Value.StartsWith("@media", StringComparison.InvariantCultureIgnoreCase))
{
fragments.Add(new MediaQuery(
selectors,
parentSelectors,
sourceLineIndex,
new ICSSFragment[0]
));
}
else
{
fragments.Add(new Selector(
selectors,
parentSelectors,
sourceLineIndex,
new ICSSFragment[0]
));
}
}
// It's very feasible that there will still be some style property value content in the buffer at this point, so ensure it
// doesn't get lost
if (stylePropertyValueBuffer.HasContent)
{
fragments.Add(stylePropertyValueBuffer.ExtractCombinedContentAndClear());
}
return(Tuple.Create <IEnumerable <ICSSFragment>, int>(fragments, sourceLineIndex - startingSourceLineIndex));
}
