/**
* If the rule was created by a macro, this method sets the appropriate values for the attributes
* generator_{name, function, location} and returns all attributes.
*
* <p>Otherwise, it returns the given attributes without any changes.
*/
private static AttributesAndLocation generatorAttributesForMacros(
BuildLangTypedAttributeValuesMap args,
@Nullable Environment env,
Location location,
Label label) {
// Returns the original arguments if a) there is only the rule itself on the stack
// trace (=> no macro) or b) the attributes have already been set by Python pre-processing.
if (env == null) {
return new AttributesAndLocation(args, location);
}
boolean hasName = args.containsAttributeNamed("generator_name");
boolean hasFunc = args.containsAttributeNamed("generator_function");
// TODO(bazel-team): resolve cases in our code where hasName && !hasFunc, or hasFunc && !hasName
if (hasName || hasFunc) {
return new AttributesAndLocation(args, location);
}
Pair<FuncallExpression, BaseFunction> topCall = env.getTopCall();
if (topCall == null || !(topCall.second instanceof UserDefinedFunction)) {
return new AttributesAndLocation(args, location);
}
FuncallExpression generator = topCall.first;
BaseFunction function = topCall.second;
String name = generator.getNameArg();
ImmutableMap.Builder<String, Object> builder = ImmutableMap.builder();
for (String attributeName : args.getAttributeNames()) {
builder.put(attributeName, args.getAttributeValue(attributeName));
}
builder.put("generator_name", (name == null) ? args.getAttributeValue("name") : name);
builder.put("generator_function", function.getName());
if (generator.getLocation() != null) {
location = generator.getLocation();
}
String relativePath = maybeGetRelativeLocation(location, label);
if (relativePath != null) {
builder.put("generator_location", relativePath);
}
try {
return new AttributesAndLocation(
new BuildLangTypedAttributeValuesMap(builder.build()), location);
} catch (IllegalArgumentException ex) {
// We just fall back to the default case and swallow any messages.
return new AttributesAndLocation(args, location);
}
}
/**
* Creates a {@link Rule} instance, adds it to the {@link Package.Builder} and returns it.
*
* @param context the package-building context in which this rule was declared
* @param ruleClass the {@link RuleClass} of the rule
* @param attributeValues a {@link BuildLangTypedAttributeValuesMap} mapping attribute names to
* attribute values of build-language type. Each attribute must be defined for this class of
* rule, and have a build-language-typed value which can be converted to the appropriate
* native type of the attribute (i.e. via {@link BuildType#selectableConvert}). There must be
* a map entry for each non-optional attribute of this class of rule.
* @param ast the abstract syntax tree of the rule expression (mandatory because this looks up a
* {@link Location} from the {@code ast})
* @param env the lexical environment of the function call which declared this rule (optional)
* @throws InvalidRuleException if the rule could not be constructed for any reason (e.g. no
* {@code name} attribute is defined)
* @throws NameConflictException if the rule's name or output files conflict with others in this
* package
* @throws InterruptedException if interrupted
*/
public static Rule createAndAddRule(
PackageContext context,
RuleClass ruleClass,
BuildLangTypedAttributeValuesMap attributeValues,
FuncallExpression ast,
@Nullable Environment env)
throws InvalidRuleException, NameConflictException, InterruptedException {
return createAndAddRule(
context.pkgBuilder,
ruleClass,
attributeValues,
context.eventHandler,
ast,
ast.getLocation(),
env);
}