[clang-doc] Allow setting a base directory for hosted pages (#132482)

Currently, when we set URLs from JS, we set them only using the protocol
and host locations. This works fine when docs are served from the base
directory of the site, but if you want to nest it under another
directory, our JS fails to set the correct path, leading to broken
links.

This patch adds a --base option to specify the path prefix to use, which
is set in the generated index_json.js file. index.json can then fill in
the prefix appropriately when generating links in a browser. This flag
has no effect for non HTML output.

Given an index hosted at: www.docs.com/base_directory/index.html
we used to generate the following link:
    www.docs.com/file.html
Using --base base_directory we now generate:
    www.docs.com/base_directory/file.html

This allows such links to work when hosting pages without using a custom
index.js.

Author: ilovepi

clang-tools-extra/clang-doc/HTMLGenerator.cpp

@@ -1078,6 +1078,11 @@ static llvm::Error serializeIndex(ClangDocContext &CDCtx) {
   std::replace(RootPathEscaped.begin(), RootPathEscaped.end(), '\\', '/');
   OS << "var RootPath = \"" << RootPathEscaped << "\";\n";
 
+  llvm::SmallString<128> Base(CDCtx.Base);
+  std::string BaseEscaped = Base.str().str();
+  std::replace(BaseEscaped.begin(), BaseEscaped.end(), '\\', '/');
+  OS << "var Base = \"" << BaseEscaped << "\";\n";
+
   CDCtx.Idx.sort();
   llvm::json::OStream J(OS, 2);
   std::function<void(Index)> IndexToJSON = [&](const Index &I) {

clang-tools-extra/clang-doc/Representation.cpp

@@ -367,10 +367,10 @@ void Index::sort() {
 ClangDocContext::ClangDocContext(tooling::ExecutionContext *ECtx,
                                  StringRef ProjectName, bool PublicOnly,
                                  StringRef OutDirectory, StringRef SourceRoot,
-                                 StringRef RepositoryUrl,
+                                 StringRef RepositoryUrl, StringRef Base,
                                  std::vector<std::string> UserStylesheets)
     : ECtx(ECtx), ProjectName(ProjectName), PublicOnly(PublicOnly),
-      OutDirectory(OutDirectory), UserStylesheets(UserStylesheets) {
+      OutDirectory(OutDirectory), UserStylesheets(UserStylesheets), Base(Base) {
   llvm::SmallString<128> SourceRootDir(SourceRoot);
   if (SourceRoot.empty())
     // If no SourceRoot was provided the current path is used as the default

clang-tools-extra/clang-doc/Representation.h

@@ -507,7 +507,7 @@ struct ClangDocContext {
   ClangDocContext() = default;
   ClangDocContext(tooling::ExecutionContext *ECtx, StringRef ProjectName,
                   bool PublicOnly, StringRef OutDirectory, StringRef SourceRoot,
-                  StringRef RepositoryUrl,
+                  StringRef RepositoryUrl, StringRef Base,
                   std::vector<std::string> UserStylesheets);
   tooling::ExecutionContext *ECtx;
   std::string ProjectName; // Name of project clang-doc is documenting.
@@ -523,6 +523,7 @@ struct ClangDocContext {
   std::vector<std::string> UserStylesheets;
   // JavaScript files that will be imported in all HTML files.
   std::vector<std::string> JsScripts;
+  StringRef Base;
   Index Idx;
 };
 

clang-tools-extra/clang-doc/assets/index.js

@@ -1,9 +1,10 @@
 function genLink(Ref) {
   // we treat the file paths different depending on if we're
   // serving via a http server or viewing from a local
-  var Path = window.location.protocol.startsWith("file") ?
-      `${window.location.protocol}//${RootPath}/${Ref.Path}` :
-      `${window.location.protocol}//${window.location.host}/${Ref.Path}`;
+  var Path = window.location.protocol.startsWith("file")
+                 ? `${window.location.protocol}//${RootPath}/${Ref.Path}`
+                 : `${window.location.protocol}//${window.location.host}/${
+                       Base}/${Ref.Path}`;
   if (Ref.RefType === "namespace") {
     Path = `${Path}/index.html`
   } else if (Ref.Path === "") {

clang-tools-extra/clang-doc/tool/ClangDocMain.cpp

@@ -67,6 +67,12 @@ static llvm::cl::opt<std::string>
                  llvm::cl::desc("Directory for outputting generated files."),
                  llvm::cl::init("docs"), llvm::cl::cat(ClangDocCategory));
 
+static llvm::cl::opt<std::string>
+    BaseDirectory("base",
+                  llvm::cl::desc(R"(Base Directory for generated documentation.
+URLs will be rooted at this directory for HTML links.)"),
+                  llvm::cl::init(""), llvm::cl::cat(ClangDocCategory));
+
 static llvm::cl::opt<bool>
     PublicOnly("public", llvm::cl::desc("Document only public declarations."),
                llvm::cl::init(false), llvm::cl::cat(ClangDocCategory));
@@ -141,8 +147,7 @@ llvm::Error getAssetFiles(clang::doc::ClangDocContext &CDCtx) {
   using DirIt = llvm::sys::fs::directory_iterator;
   std::error_code FileErr;
   llvm::SmallString<128> FilePath(UserAssetPath);
-  for (DirIt DirStart = DirIt(UserAssetPath, FileErr),
-                   DirEnd;
+  for (DirIt DirStart = DirIt(UserAssetPath, FileErr), DirEnd;
        !FileErr && DirStart != DirEnd; DirStart.increment(FileErr)) {
     FilePath = DirStart->path();
     if (llvm::sys::fs::is_regular_file(FilePath)) {
@@ -268,8 +273,8 @@ Example usage for a project using a compile commands database:
       OutDirectory,
       SourceRoot,
       RepositoryUrl,
-      {UserStylesheets.begin(), UserStylesheets.end()}
-  };
+      BaseDirectory,
+      {UserStylesheets.begin(), UserStylesheets.end()}};
 
   if (Format == "html") {
     if (auto Err = getHtmlAssetFiles(argv[0], CDCtx)) {

clang-tools-extra/test/clang-doc/assets.cpp

@@ -1,5 +1,5 @@
 // RUN: rm -rf %t && mkdir %t
-// RUN: clang-doc --format=html --output=%t --asset=%S/Inputs/test-assets --executor=standalone %s
+// RUN: clang-doc --format=html --output=%t --asset=%S/Inputs/test-assets --executor=standalone %s --base base_dir
 // RUN: FileCheck %s -input-file=%t/index.html -check-prefix=INDEX
 // RUN: FileCheck %s -input-file=%t/test.css -check-prefix=CSS
 // RUN: FileCheck %s -input-file=%t/test.js -check-prefix=JS
@@ -19,4 +19,4 @@
 // CSS-NEXT:     padding: 0;
 // CSS-NEXT: }
 
-// JS: console.log("Hello, world!");
+// JS: console.log("Hello, world!");

clang-tools-extra/test/clang-doc/test-path-abs.cpp

@@ -1,5 +1,7 @@
 // RUN: rm -rf %t && mkdir -p %t
-// RUN: clang-doc --format=html --executor=standalone %s --output=%t
+// RUN: clang-doc --format=html --executor=standalone %s --output=%t --base base_dir
 // RUN: FileCheck %s -input-file=%t/index_json.js  -check-prefix=JSON-INDEX
 
 // JSON-INDEX: var RootPath = "{{.*}}test-path-abs.cpp.tmp";
+// JSON-INDEX-NEXT: var Base = "base_dir";
+

clang-tools-extra/unittests/clang-doc/HTMLGeneratorTest.cpp

@@ -28,9 +28,9 @@ std::unique_ptr<Generator> getHTMLGenerator() {
 
 ClangDocContext
 getClangDocContext(std::vector<std::string> UserStylesheets = {},
-                   StringRef RepositoryUrl = "") {
-  ClangDocContext CDCtx{
-      {}, "test-project", {}, {}, {}, RepositoryUrl, UserStylesheets};
+                   StringRef RepositoryUrl = "", StringRef Base = "") {
+  ClangDocContext CDCtx{{}, "test-project", {},   {},
+                        {}, RepositoryUrl,  Base, UserStylesheets};
   CDCtx.UserStylesheets.insert(
       CDCtx.UserStylesheets.begin(),
       "../share/clang/clang-doc-default-stylesheet.css");