Compiler for the JSON Traversal Language.

chrome/tools/profile_reset/jtl_compiler.cc

Index: chrome/tools/profile_reset/jtl_compiler.cc
diff --git a/chrome/tools/profile_reset/jtl_compiler.cc b/chrome/tools/profile_reset/jtl_compiler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5f6e624d88410bd7ce822e4a0e822d2017cae502
--- /dev/null
+++ b/chrome/tools/profile_reset/jtl_compiler.cc
@@ -0,0 +1,182 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/tools/profile_reset/jtl_compiler.h"
+
+#include <algorithm>
+#include <map>
+#include <string>
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string_util.h"
+#include "chrome/browser/profile_resetter/jtl_foundation.h"
+#include "chrome/tools/profile_reset/jtl_parser.h"
+
+namespace jtl = jtl_foundation;
+
+namespace {
+
+// Serializes symbols into byte-code in a streaming manner.
+class ByteCodeWriter {
+ public:
+  explicit ByteCodeWriter(std::string* output) : output_(output) {}
+  ~ByteCodeWriter() {}
+
+  void WriteUint8(uint8 value) { output_->push_back(static_cast<char>(value)); }
+  void WriteOpCode(uint8 op_code) { WriteUint8(op_code); }
+  void WriteHash(const std::string& hash) {
+    CHECK(hash.size() == jtl::kHashSizeInBytes);
+    *output_ += hash;
+  }
+  void WriteBool(bool value) { WriteUint8(value ? 1u : 0u); }
+
+ private:
+  std::string* output_;
+
+  DISALLOW_COPY_AND_ASSIGN(ByteCodeWriter);
+};
+
+// Encapsulates meta-data about all instructions, and is capable of transcoding
+// each instruction from a parsed text-based format to byte-code.
+class InstructionSet {
+ public:
+  InstructionSet() {
+    // Define new instructions in this list.
+    Add(Instruction("node", jtl::NAVIGATE, Arguments(Hash)));
+    Add(Instruction("any", jtl::NAVIGATE_ANY, Arguments()));
+    Add(Instruction("back", jtl::NAVIGATE_BACK, Arguments()));
+    Add(Instruction("store_bool", jtl::STORE_BOOL, Arguments(Hash, Bool)));
+    Add(Instruction("compare_stored_bool",
+                    jtl::COMPARE_STORED_BOOL,
+                    Arguments(Hash, Bool, Bool)));
+    Add(Instruction("store_hash", jtl::STORE_HASH, Arguments(Hash, Hash)));
+    Add(Instruction("compare_stored_hash",
+                    jtl::COMPARE_STORED_HASH,
+                    Arguments(Hash, Hash, Hash)));
+    Add(Instruction("compare_bool", jtl::COMPARE_NODE_BOOL, Arguments(Bool)));
+    Add(Instruction("compare_hash", jtl::COMPARE_NODE_HASH, Arguments(Hash)));
+    Add(Instruction("break", jtl::STOP_EXECUTING_SENTENCE, Arguments()));
+  }
+
+  bool TranscodeInstruction(const std::string& name,
+                            const ListValue& arguments,
+                            bool end_of_sentence,
+                            const jtl::Hasher& hasher,
+                            ByteCodeWriter* target) const {
+    if (instruction_map_.count(name) == 0)
+      return false;
+    const Instruction& instruction(instruction_map_.at(name));
+    if (instruction.argument_types.size() != arguments.GetSize())
+      return false;
+    target->WriteOpCode(instruction.op_code);
+    for (size_t i = 0; i < arguments.GetSize(); ++i) {
+      switch (instruction.argument_types[i]) {
+        case Bool: {
+          bool value;
+          if (!arguments.GetBoolean(i, &value))
+            return false;
+          target->WriteBool(value);
+          break;
+        }
+        case Hash: {
+          std::string value;
+          if (!arguments.GetString(i, &value))
+            return false;
+          target->WriteHash(hasher.GetHash(value));
+          break;
+        }
+        default:
+          NOTREACHED();
+          return false;
+      }
+    }
+    if (end_of_sentence)
+      target->WriteOpCode(jtl::END_OF_SENTENCE);
+    return true;
+  }
+
+ private:
+  // The possible types of an operation's argument.
+  enum ArgumentType {
+    None,
+    Bool,
+    Hash
+  };
+
+  // Encapsulates meta-data about one instruction.
+  struct Instruction {
+    Instruction() : op_code(jtl::END_OF_SENTENCE) {}
+    Instruction(const char* name,
+                jtl_foundation::OpCodes op_code,
+                const std::vector<ArgumentType>& argument_types)
+        : name(name), op_code(op_code), argument_types(argument_types) {}
+
+    std::string name;
+    jtl::OpCodes op_code;
+    std::vector<ArgumentType> argument_types;
+  };
+
+  static std::vector<ArgumentType> Arguments(ArgumentType arg1_type = None,
+                                             ArgumentType arg2_type = None,
+                                             ArgumentType arg3_type = None) {
+    std::vector<ArgumentType> result;
+    if (arg1_type != None)
+      result.push_back(arg1_type);
+    if (arg2_type != None)
+      result.push_back(arg2_type);
+    if (arg3_type != None)
+      result.push_back(arg3_type);
+    return result;
+  }
+
+  void Add(const Instruction& instruction) {
+    instruction_map_[instruction.name] = instruction;
+  }
+
+  std::map<std::string, Instruction> instruction_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(InstructionSet);
+};
+
+}  // namespace
+
+bool JtlCompiler::Compile(const std::string& source_code,
+                          const std::string& hash_seed,
+                          std::string* output_bytecode,
+                          CompileError* error_details) {
+  DCHECK(output_bytecode);
+  InstructionSet instruction_set;
+  ByteCodeWriter bytecode_writer(output_bytecode);
+  jtl::Hasher hasher(hash_seed);
+  scoped_ptr<JtlParser> parser(JtlParser::Create(source_code));
+  while (parser->HasNextOperation()) {
+    std::string operation_name;
+    ListValue arguments;
+    bool end_of_sentence;

[battre, 2013/09/27 15:00:01]

nit: initialize to false

[engedy, 2013/10/01 10:48:10]

Done.

+    if (!parser->ParseNextOperation(
+             &operation_name, &arguments, &end_of_sentence)) {
+      if (error_details) {
+        error_details->context = parser->last_context();
+        error_details->line_number = parser->last_line_number();
+        error_details->error_code = CompileError::PARSING_ERROR;
+      }
+      return false;
+    }
+    if (!instruction_set.TranscodeInstruction(operation_name,
+                                              arguments,
+                                              end_of_sentence,
+                                              hasher,
+                                              &bytecode_writer)) {
+      if (error_details) {
+        error_details->context = parser->last_context();
+        error_details->line_number = parser->last_line_number();
+        error_details->error_code = CompileError::UNKNOWN_OPERATION;
+      }
+      return false;
+    }
+  }
+
+  return true;
+}