[clang-tools-extra] [llvm] [llvm] add support for mustache templating language (PR #105893)

[Paul Kirth via cfe-commits]

================
@@ -0,0 +1,730 @@
+//===-- Mustache.cpp ------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Mustache.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/raw_ostream.h"
+#include <sstream>
+
+using namespace llvm;
+using namespace llvm::json;
+
+namespace llvm {
+namespace mustache {
+namespace {
+
+class Token {
+public:
+  enum class Type {
+    Text,
+    Variable,
+    Partial,
+    SectionOpen,
+    SectionClose,
+    InvertSectionOpen,
+    UnescapeVariable,
+    Comment,
+  };
+
+  Token(std::string Str);
+
+  Token(std::string RawBody, std::string TokenBody, char Identifier);
+
+  StringRef getTokenBody() const { return TokenBody; };
+
+  StringRef getRawBody() const { return RawBody; };
+
+  void setTokenBody(std::string NewBody) { TokenBody = std::move(NewBody); };
+
+  Accessor getAccessor() const { return Accessor; };
+
+  Type getType() const { return TokenType; };
+
+  void setIndentation(size_t NewIndentation) { Indentation = NewIndentation; };
+
+  size_t getIndentation() const { return Indentation; };
+
+  static Type getTokenType(char Identifier);
+
+private:
+  Type TokenType;
+  // RawBody is the original string that was tokenized
+  std::string RawBody;
+  // TokenBody is the original string with the identifier removed
+  std::string TokenBody;
+  Accessor Accessor;
+  size_t Indentation;
+};
+
+class ASTNode {
+public:
+  enum Type {
+    Root,
+    Text,
+    Partial,
+    Variable,
+    UnescapeVariable,
+    Section,
+    InvertSection,
+  };
+
+  ASTNode() : T(Type::Root), ParentContext(nullptr) {};
+
+  ASTNode(StringRef Body, ASTNode *Parent)
+      : T(Type::Text), Body(Body), Parent(Parent), ParentContext(nullptr) {};
+
+  // Constructor for Section/InvertSection/Variable/UnescapeVariable
+  ASTNode(Type T, Accessor Accessor, ASTNode *Parent)
+      : T(T), Parent(Parent), Children({}), Accessor(Accessor),
+        ParentContext(nullptr) {};
+
+  void addChild(ASTNode *Child) { Children.emplace_back(Child); };
+
+  void setRawBody(std::string NewBody) { RawBody = std::move(NewBody); };
+
+  void setIndentation(size_t NewIndentation) { Indentation = NewIndentation; };
+
+  void render(const llvm::json::Value &Data, llvm::raw_ostream &OS);
+
+  void setUpNode(llvm::BumpPtrAllocator &Alloc, StringMap<ASTNode *> &Partials,
+                 StringMap<Lambda> &Lambdas,
+                 StringMap<SectionLambda> &SectionLambdas,
+                 DenseMap<char, std::string> &Escapes);
+
+private:
+  void renderLambdas(const llvm::json::Value &Contexts, llvm::raw_ostream &OS,
+                     Lambda &L);
+
+  void renderSectionLambdas(const llvm::json::Value &Contexts,
+                            llvm::raw_ostream &OS, SectionLambda &L);
+
+  void renderPartial(const llvm::json::Value &Contexts, llvm::raw_ostream &OS,
+                     ASTNode *Partial);
+
+  void renderChild(const llvm::json::Value &Context, llvm::raw_ostream &OS);
+
+  const llvm::json::Value *findContext();
+
+  llvm::BumpPtrAllocator *Allocator;
+  StringMap<ASTNode *> *Partials;
+  StringMap<Lambda> *Lambdas;
+  StringMap<SectionLambda> *SectionLambdas;
+  DenseMap<char, std::string> *Escapes;
+  Type T;
+  size_t Indentation = 0;
+  std::string RawBody;
+  std::string Body;
+  ASTNode *Parent;
+  // TODO: switch implementation to SmallVector<T>
+  std::vector<ASTNode *> Children;
+  const Accessor Accessor;
+  const llvm::json::Value *ParentContext;
+};
+
+// Custom stream to escape strings
----------------
ilovepi wrote:

```suggestion
// Custom stream to escape strings.
```

https://github.com/llvm/llvm-project/pull/105893