Clang based header generator: Refactor emitter

This CL moves additional functions and template strings to EmitterBase as we are going to use them in the new emitter. PiperOrigin-RevId: 643321889 Change-Id: Iba50388141ff9fd978980becd4af22176a5d5842
google · Jun 14, 2024 · 131826f · 131826f
1 parent cfa374b
commit 131826f
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Showing 4 changed files with 88 additions and 124 deletions.
diff --git a/sandboxed_api/tools/clang_generator/emitter.cc b/sandboxed_api/tools/clang_generator/emitter.cc
@@ -14,18 +14,14 @@
 
 #include "sandboxed_api/tools/clang_generator/emitter.h"
 
-#include <cstdint>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "absl/container/flat_hash_set.h"
 #include "absl/log/log.h"
-#include "absl/random/random.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
-#include "absl/strings/ascii.h"
-#include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_format.h"
 #include "absl/strings/str_join.h"
@@ -46,18 +42,18 @@
 
 namespace sapi {
 
+// Common header description with auto-generation notice.
+constexpr absl::string_view kHeaderDescription =
+    R"(// AUTO-GENERATED by the Sandboxed API generator.
+// Edits will be discarded when regenerating this file.)";
+
 // Common header file prolog with auto-generation notice.
 // Note: The includes will be adjusted by Copybara when converting to/from
 //       internal code. This is intentional.
 // Text template arguments:
 //   1. Header guard
-constexpr absl::string_view kHeaderProlog =
-    R"(// AUTO-GENERATED by the Sandboxed API generator.
-// Edits will be discarded when regenerating this file.
-
-#ifndef %1$s
-#define %1$s
-
+constexpr absl::string_view kHeaderIncludes =
+    R"(
 #include <cstdint>
 #include <type_traits>
 
@@ -70,33 +66,12 @@ constexpr absl::string_view kHeaderProlog =
 
 )";
 
-// Text template arguments:
-//   1. Header guard
-constexpr absl::string_view kHeaderEpilog =
-    R"(
-#endif  // %1$s)";
-
 // Text template arguments:
 //   1. Include for embedded sandboxee objects
 constexpr absl::string_view kEmbedInclude = R"(#include "%1$s_embed.h"
 
 )";
 
-// Text template arguments:
-//   1. Namespace name
-constexpr absl::string_view kNamespaceBeginTemplate =
-    R"(
-namespace %1$s {
-
-)";
-
-// Text template arguments:
-//   1. Namespace name
-constexpr absl::string_view kNamespaceEndTemplate =
-    R"(
-}  // namespace %1$s
-)";
-
 // Text template arguments:
 //   1. Class name
 //   2. Embedded object identifier
@@ -136,38 +111,13 @@ constexpr absl::string_view kClassFooterTemplate = R"(
 };
 )";
 
-std::string GetIncludeGuard(absl::string_view filename) {
-  if (filename.empty()) {
-    static auto* bit_gen = new absl::BitGen();
-    return absl::StrCat(
-        // Copybara will transform the string. This is intentional.
-        "SANDBOXED_API_GENERATED_HEADER_",
-        absl::AsciiStrToUpper(absl::StrCat(
-            absl::Hex(absl::Uniform<uint64_t>(*bit_gen), absl::kZeroPad16))),
-        "_");
+// Returns a unique name for a parameter. If `decl` has no name, a unique name
+// will be generated in the form of `unnamed<index>_`.
+std::string GetParamName(const clang::ParmVarDecl* decl, int index) {
+  if (std::string name = decl->getName().str(); !name.empty()) {
+    return absl::StrCat(name, "_");  // Suffix to avoid collisions
   }
-
-  constexpr absl::string_view kUnderscorePrefix = "SAPI_";
-  std::string guard;
-  guard.reserve(filename.size() + kUnderscorePrefix.size() + 1);
-  for (auto c : filename) {
-    if (absl::ascii_isalpha(c)) {
-      guard += absl::ascii_toupper(c);
-      continue;
-    }
-    if (guard.empty()) {
-      guard = kUnderscorePrefix;
-    }
-    if (absl::ascii_isdigit(c)) {
-      guard += c;
-    } else if (guard.back() != '_') {
-      guard += '_';
-    }
-  }
-  if (!absl::EndsWith(guard, "_")) {
-    guard += '_';
-  }
-  return guard;
+  return absl::StrCat("unnamed", index, "_");
 }
 
 // Returns a comment for the given function `decl` which represents the
@@ -305,7 +255,10 @@ absl::StatusOr<std::string> EmitHeader(
   }
   std::string out;
   const std::string include_guard = GetIncludeGuard(options.out_file);
+  absl::StrAppend(&out, kHeaderDescription);
   absl::StrAppendFormat(&out, kHeaderProlog, include_guard);
+  absl::StrAppend(&out, kHeaderIncludes);
+
   // When embedding the sandboxee, add embed header include
   if (!options.embed_name.empty()) {
     // Not using JoinPath() because even on Windows include paths use plain

diff --git a/sandboxed_api/tools/clang_generator/emitter.h b/sandboxed_api/tools/clang_generator/emitter.h
@@ -20,7 +20,6 @@
 
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
-#include "absl/strings/string_view.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/Type.h"
 #include "sandboxed_api/tools/clang_generator/emitter_base.h"
@@ -48,14 +47,6 @@ class Emitter : public EmitterBase {
   std::vector<std::string> rendered_functions_ordered_;
 };
 
-// Constructs an include guard name for the given filename. The name is of the
-// same form as the include guards in this project and conforms to the Google
-// C++ style. For example,
-//   sandboxed_api/examples/zlib/zlib-sapi.sapi.h
-// will be mapped to
-//   SANDBOXED_API_EXAMPLES_ZLIB_ZLIB_SAPI_SAPI_H_
-std::string GetIncludeGuard(absl::string_view filename);
-
 }  // namespace sapi
 
 #endif  // SANDBOXED_API_TOOLS_CLANG_GENERATOR_EMITTER_H_
diff --git a/sandboxed_api/tools/clang_generator/emitter_base.cc b/sandboxed_api/tools/clang_generator/emitter_base.cc
@@ -15,14 +15,18 @@
 #include "sandboxed_api/tools/clang_generator/emitter_base.h"
 
 #include <algorithm>
+#include <cstdint>
 #include <string>
 #include <vector>
 
+#include "absl/random/random.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
+#include "absl/strings/ascii.h"
 #include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
+#include "absl/strings/string_view.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclCXX.h"
@@ -38,57 +42,12 @@
 
 namespace sapi {
 
-// Common header file prolog with auto-generation notice.
-// Note: The includes will be adjusted by Copybara when converting to/from
-//       internal code. This is intentional.
-// Text template arguments:
-//   1. Header guard
-constexpr absl::string_view kHeaderProlog =
-    R"(// AUTO-GENERATED by the Sandboxed API generator.
-// Edits will be discarded when regenerating this file.
-
-#ifndef %1$s
-#define %1$s
-
-#include <cstdint>
-#include <type_traits>
-
-#include "absl/base/macros.h"
-#include "absl/status/status.h"
-#include "absl/status/statusor.h"
-#include "sandboxed_api/sandbox.h"
-#include "sandboxed_api/util/status_macros.h"
-#include "sandboxed_api/vars.h"
-
-)";
-
-// Text template arguments:
-//   1. Header guard
-constexpr absl::string_view kHeaderEpilog =
-    R"(
-#endif  // %1$s)";
-
 // Text template arguments:
 //   1. Include for embedded sandboxee objects
 constexpr absl::string_view kEmbedInclude = R"(#include "%1$s_embed.h"
 
 )";
 
-// Text template arguments:
-//   1. Namespace name
-constexpr absl::string_view kNamespaceBeginTemplate =
-    R"(
-namespace %1$s {
-
-)";
-
-// Text template arguments:
-//   1. Namespace name
-constexpr absl::string_view kNamespaceEndTemplate =
-    R"(
-}  // namespace %1$s
-)";
-
 // Text template arguments:
 //   1. Class name
 //   2. Embedded object identifier
@@ -248,11 +207,38 @@ std::string GetSpelling(const clang::Decl* decl) {
 
 }  // namespace
 
-std::string GetParamName(const clang::ParmVarDecl* decl, int index) {
-  if (std::string name = decl->getName().str(); !name.empty()) {
-    return absl::StrCat(name, "_");  // Suffix to avoid collisions
+std::string GetIncludeGuard(absl::string_view filename) {
+  if (filename.empty()) {
+    static auto* bit_gen = new absl::BitGen();
+    return absl::StrCat(
+        // Copybara will transform the string. This is intentional.
+        "SANDBOXED_API_GENERATED_HEADER_",
+        absl::AsciiStrToUpper(absl::StrCat(
+            absl::Hex(absl::Uniform<uint64_t>(*bit_gen), absl::kZeroPad16))),
+        "_");
+  }
+
+  constexpr absl::string_view kUnderscorePrefix = "SAPI_";
+  std::string guard;
+  guard.reserve(filename.size() + kUnderscorePrefix.size() + 1);
+  for (auto c : filename) {
+    if (absl::ascii_isalpha(c)) {
+      guard += absl::ascii_toupper(c);
+      continue;
+    }
+    if (guard.empty()) {
+      guard = kUnderscorePrefix;
+    }
+    if (absl::ascii_isdigit(c)) {
+      guard += c;
+    } else if (guard.back() != '_') {
+      guard += '_';
+    }
+  }
+  if (!absl::EndsWith(guard, "_")) {
+    guard += '_';
   }
-  return absl::StrCat("unnamed", index, "_");
+  return guard;
 }
 
 void EmitterBase::EmitType(clang::TypeDecl* type_decl) {

diff --git a/sandboxed_api/tools/clang_generator/emitter_base.h b/sandboxed_api/tools/clang_generator/emitter_base.h
@@ -23,6 +23,7 @@
 #include "absl/container/node_hash_set.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
+#include "absl/strings/string_view.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/Type.h"
 
@@ -40,6 +41,36 @@ absl::StatusOr<std::string> ReformatGoogleStyle(const std::string& filename,
 
 }  // namespace internal
 
+// Text template arguments:
+//   1. Namespace name
+inline constexpr absl::string_view kNamespaceBeginTemplate =
+    R"(
+namespace %1$s {
+
+)";
+
+// Text template arguments:
+//   1. Namespace name
+inline constexpr absl::string_view kNamespaceEndTemplate =
+    R"(
+}  // namespace %1$s
+)";
+
+// Text template arguments:
+//   1. Header guard
+inline constexpr absl::string_view kHeaderProlog =
+    R"(
+#ifndef %1$s
+#define %1$s
+
+)";
+
+// Text template arguments:
+//   1. Header guard
+inline constexpr absl::string_view kHeaderEpilog =
+    R"(
+#endif  // %1$s)";
+
 class RenderedType {
  public:
   RenderedType(std::string ns_name, std::string spelling)
@@ -89,9 +120,12 @@ class EmitterBase {
   void EmitType(clang::TypeDecl* type_decl);
 };
 
-// Returns a unique name for a parameter. If `decl` has no name, a unique name
-// will be generated in the form of `unnamed<index>_`.
-std::string GetParamName(const clang::ParmVarDecl* decl, int index);
+// Constructs an include guard for the given filename. The generated string
+// conforms to the Google C++ style. For example,
+//   sandboxed_api/examples/zlib/zlib-sapi.sapi.h
+// will be mapped to
+//   SANDBOXED_API_EXAMPLES_ZLIB_ZLIB_SAPI_SAPI_H_
+std::string GetIncludeGuard(absl::string_view filename);
 
 }  // namespace sapi