/// <summary>
/// Populate the lists of evaluated and unevaluated metadata with all metadata that have true conditions.
/// </summary>
/// <remarks>
/// FUTURE: Currently this isn't done when the item is constructed; so for example HasMetadata will always return
/// false until EvaluatedAllItemMetadata is explicitly called. The reason for this is that Metadata are
/// not first class objects, they are merely string pairs produced by running over the child XML with a particular expander.
/// When Metadata are first class objects this method can be changed to merely evaluate them,
/// just as BuildItemGroup.Evaluate does for BuildItem, then methods like HasMetadata behave more sanely. Of course this
/// could be a breaking change.
/// </remarks>
internal void EvaluateAllItemMetadata
(
Expander expander,
ParserOptions parserOptions,
EngineLoggingServices loggingServices,
BuildEventContext buildEventContext
)
{
ErrorUtilities.VerifyThrow(expander != null, "Null expander passed in.");
// Cache all custom attributes on the item. For a persisted item, this will walk the item's child nodes, and
// cache the custom attributes using a "last one wins" policy. For a virtual item, this method does nothing.
// We only evaluate metadata by reading XML
if (IsBackedByXml)
{
ErrorUtilities.VerifyThrow((this.evaluatedCustomMetadata != null) && (this.unevaluatedCustomMetadata != null),
"Item is not initialized properly.");
// We're evaluating from scratch, so clear out any old cached attributes.
this.evaluatedCustomMetadata.Clear();
this.unevaluatedCustomMetadata.Clear();
// Let the expander know about our own item type, so it can
// expand unqualified metadata expressions
SpecificItemDefinitionLibrary specificItemDefinitionLibrary = new SpecificItemDefinitionLibrary(name, itemDefinitionLibrary);
expander = new Expander(expander, specificItemDefinitionLibrary);
List<XmlElement> metadataElements = xml.GetChildren();
// look at all the item's child nodes
foreach (XmlElement metadataElement in metadataElements)
{
// confirm that the child node is not conditionally disabled
bool condition = true;
XmlAttribute conditionAttribute = ProjectXmlUtilities.GetConditionAttribute(metadataElement, true /*no other attributes allowed*/);
if (conditionAttribute != null)
{
condition = Utilities.EvaluateCondition(conditionAttribute.Value,
conditionAttribute, expander, null, parserOptions,
loggingServices, buildEventContext);
}
if (condition)
{
// cache its value, both the evaluated and unevaluated.
string unevaluatedMetadataValue = Utilities.GetXmlNodeInnerContents(metadataElement);
unevaluatedCustomMetadata[metadataElement.Name] = unevaluatedMetadataValue;
string evaluatedMetadataValue = expander.ExpandAllIntoStringLeaveEscaped(unevaluatedMetadataValue, metadataElement);
evaluatedCustomMetadata[metadataElement.Name] = evaluatedMetadataValue;
// Add this metadata to the running table we're using, so that one piece of metadata can refer to another one above
expander.SetMetadataInMetadataTable(name, metadataElement.Name, evaluatedMetadataValue);
}
}
}
}
internal Expander(Expander expander, SpecificItemDefinitionLibrary itemDefinitionLibrary)
: this(expander.lookup, null , expander.options)
{
if (implicitMetadataItemType == null)
{
this.itemMetadata = expander.itemMetadata;
}
this.specificItemDefinitionLibrary = itemDefinitionLibrary;
}
