// Copyright 2014 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.docgen;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;
/**
* Helper class used for expanding link references in rule and attribute documentation.
*
* <p>See {@link com.google.devtools.build.docgen.DocgenConsts.BLAZE_RULE_LINK} for the regex used
* to match link references.
*/
public class RuleLinkExpander {
private static final String EXAMPLES_SUFFIX = "_examples";
private static final String ARGS_SUFFIX = "_args";
private static final String IMPLICIT_OUTPUTS_SUFFIX = "_implicit_outputs";
private static final String FUNCTIONS_PAGE = "functions";
private static final ImmutableSet<String> STATIC_PAGES =
ImmutableSet.<String>of(
"common-definitions", "make-variables", "predefined-python-variables");
private static final ImmutableMap<String, String> FUNCTIONS =
ImmutableMap.<String, String>builder()
.put("load", FUNCTIONS_PAGE)
.put("package", FUNCTIONS_PAGE)
.put("package_group", FUNCTIONS_PAGE)
.put("description", FUNCTIONS_PAGE)
.put("distribs", FUNCTIONS_PAGE)
.put("licenses", FUNCTIONS_PAGE)
.put("exports_files", FUNCTIONS_PAGE)
.put("glob", FUNCTIONS_PAGE)
.put("select", FUNCTIONS_PAGE)
.put("workspace", FUNCTIONS_PAGE)
.build();
private final String productName;
private final Map<String, String> ruleIndex = new HashMap<>();
private final boolean singlePage;
RuleLinkExpander(String productName, Map<String, String> ruleIndex, boolean singlePage) {
this.productName = productName;
this.ruleIndex.putAll(ruleIndex);
this.ruleIndex.putAll(FUNCTIONS);
this.singlePage = singlePage;
}
RuleLinkExpander(String productName, boolean singlePage) {
this.productName = productName;
this.ruleIndex.putAll(FUNCTIONS);
this.singlePage = singlePage;
}
public void addIndex(Map<String, String> ruleIndex) {
this.ruleIndex.putAll(ruleIndex);
}
private void appendRuleLink(Matcher matcher, StringBuffer sb, String ruleName, String ref) {
String ruleFamily = ruleIndex.get(ruleName);
String link = singlePage
? "#" + ref
: ruleFamily + ".html#" + ref;
matcher.appendReplacement(sb, Matcher.quoteReplacement(link));
}
/*
* Match and replace all ${link rule.attribute} references.
*/
private String expandRuleLinks(String htmlDoc) throws IllegalArgumentException {
Matcher matcher = DocgenConsts.BLAZE_RULE_LINK.matcher(htmlDoc);
StringBuffer sb = new StringBuffer(htmlDoc.length());
while (matcher.find()) {
// The first capture group matches the entire reference, e.g. "cc_binary.deps".
String ref = matcher.group(1);
// The second capture group only matches the rule name, e.g. "cc_binary" in "cc_binary.deps".
String name = matcher.group(2);
// The name in the reference is the name of a rule. Get the rule family for the rule and
// replace the reference with a link with the form of rule-family.html#rule.attribute. For
// example, ${link cc_library.deps} expands to c-cpp.html#cc_library.deps.
if (ruleIndex.containsKey(name)) {
appendRuleLink(matcher, sb, name, ref);
continue;
}
// The name is referencing the examples, arguments, or implicit outputs of a rule (e.g.
// "cc_library_args", "cc_library_examples", or "java_binary_implicit_outputs"). Strip the
// suffix and then try matching the name to a rule family.
if (name.endsWith(EXAMPLES_SUFFIX)
|| name.endsWith(ARGS_SUFFIX)
|| name.endsWith(IMPLICIT_OUTPUTS_SUFFIX)) {
int endIndex;
if (name.endsWith(EXAMPLES_SUFFIX)) {
endIndex = name.indexOf(EXAMPLES_SUFFIX);
} else if (name.endsWith(ARGS_SUFFIX)) {
endIndex = name.indexOf(ARGS_SUFFIX);
} else {
endIndex = name.indexOf(IMPLICIT_OUTPUTS_SUFFIX);
}
String ruleName = name.substring(0, endIndex);
if (ruleIndex.containsKey(ruleName)) {
appendRuleLink(matcher, sb, ruleName, ref);
continue;
}
}
// The name is not the name of a rule but is the name of a static page, such as
// common-definitions. Generate a link to that page.
if (STATIC_PAGES.contains(name)) {
String link = singlePage
? "#" + name
: name + ".html";
// For referencing headings on a static page, use the following syntax:
// ${link static_page_name#heading_name}, example: ${link make-variables#gendir}
String pageHeading = matcher.group(4);
if (pageHeading != null) {
throw new IllegalArgumentException(
"Invalid link syntax for BE page: " + matcher.group()
+ "\nUse ${link static-page#heading} syntax instead.");
}
matcher.appendReplacement(sb, Matcher.quoteReplacement(link));
continue;
}
// If the reference does not match any rule or static page, throw an exception.
throw new IllegalArgumentException(
"Rule family " + name + " in link tag does not match any rule or BE page: "
+ matcher.group());
}
matcher.appendTail(sb);
return sb.toString();
}
/*
* Match and replace all ${link rule#heading} references.
*/
private String expandRuleHeadingLinks(String htmlDoc) throws IllegalArgumentException {
Matcher matcher = DocgenConsts.BLAZE_RULE_HEADING_LINK.matcher(htmlDoc);
StringBuffer sb = new StringBuffer(htmlDoc.length());
while (matcher.find()) {
// The second capture group only matches the rule name, e.g. "cc_library" in
// "cc_library#some_heading"
String name = matcher.group(2);
// The third capture group only matches the heading, e.g. "some_heading" in
// "cc_library#some_heading"
String heading = matcher.group(3);
// The name in the reference is the name of a rule. Get the rule family for the rule and
// replace the reference with the link in the form of rule-family.html#heading. Examples of
// this include custom <a name="heading"> tags in the description or examples for the rule.
if (ruleIndex.containsKey(name)) {
String ruleFamily = ruleIndex.get(name);
String link = singlePage
? "#" + heading
: ruleFamily + ".html#" + heading;
matcher.appendReplacement(sb, Matcher.quoteReplacement(link));
continue;
}
// The name is of a static page, such as common.definitions. Generate a link to that page, and
// append the page heading. For example, ${link common-definitions#label-expansion} expands to
// common-definitions.html#label-expansion.
if (STATIC_PAGES.contains(name)) {
String link = singlePage
? "#" + heading
: name + ".html#" + heading;
matcher.appendReplacement(sb, Matcher.quoteReplacement(link));
continue;
}
// Links to the user manual are handled specially. Meh.
if ("user-manual".equals(name)) {
String link = productName.toLowerCase(Locale.US) + "-" + name + ".html#" + heading;
matcher.appendReplacement(sb, Matcher.quoteReplacement(link));
continue;
}
// If the reference does not match any rule or static page, throw an exception.
throw new IllegalArgumentException(
"Rule family " + name + " in link tag does not match any rule or BE page: "
+ matcher.group());
}
matcher.appendTail(sb);
return sb.toString();
}
/**
* Expands all rule references in the input HTML documentation.
*
* @param htmlDoc The input HTML documentation with ${link foo.bar} references.
* @return The HTML documentation with all link references expanded.
*/
public String expand(String htmlDoc) throws IllegalArgumentException {
String expanded = expandRuleLinks(htmlDoc);
return expandRuleHeadingLinks(expanded);
}
/**
* Expands the rule reference.
*
* <p>This method is used to expand references in the BE velocity templates.
*
* @param ref The rule reference to expand.
* @return The expanded rule reference.
*/
public String expandRef(String ref) throws IllegalArgumentException {
return expand("${link " + ref + "}");
}
}