Files
flatbuffers/src/code_generators.cpp
Wouter van Oortmerssen 7b94eab2b1 Add CodeWriter utility class.
Helps simplify code generation code.  Instead of this:
  code += "inline const " + cpp_qualified_name + " *Get";
  code += name;
  code += "(const void *buf) {\n  return flatbuffers::GetRoot<";
  code += cpp_qualified_name + ">(buf);\n}\n\n";

You do this:
  code.SetValue("NAME", struct_def.name);
  code.SetValue("CPP_NAME", cpp_qualified_name);
  code += "inline const {{CPP_NAME}} *Get{{NAME}}(const void *buf) {";
  code += "  return flatbuffers::GetRoot<{{CPP_NAME}}>(buf);";
  code += "}";
  code += "";

Updated the CPP code generator to use the CodeWriter class.  Most of the
changes in the generated code are white-space changes, esp. around new
lines (since the code generator class automatically appends new lines
when appending a string).  Actual code changes include:

* Renamed "rehasher" to "_rehasher" for consistency with other args in
  Pack function.

* Renamed "union_obj" to "obj: in UnPack function.

* Always do "(void)_o;" to prevent unused variable warning in Create
  function (instead of only doing it if there are no fields) in order
  to avoid two-passes.

* Renamed padding variables from __paddingX to paddingX__.
  "Each name that contains a double underscore (_ _) [...] is reserved
   to the implementation for any use."  C++ standards 17.4.3.1.2.

* Add braces around switch cases.

* Calculate index as a separate statement in EnumName function, eg.
    const size_t index = ...;
    return EnumNamesX()[index];
  vs.
    return EnumNamesX()[...];

* Stored end table offset in variable in Finish() functions, eg.
    const auto end = fbb_.EndTable(start_, ...);
    auto o = flatbuffers::Offset<T>(end);
  vs.
    auto o = flatbuffers::Offset<T>(fbb_.EndTable(start, ...));

* Separate reinterpret_cast calls from function calls in Union
  functions, eg.
    auto ptr = reinterpret_cast<const T *>(obj);
    return ptr->UnPack(resolver);
  vs.
    return reinterpret_cast<const T *>(obj)->UnPack(resolver);

* Removed unecessary (void)(padding__X) no-ops from constructors, eg.
    Test(int16_t a, int8_t b) : ... {
      (void)__padding0;  // <-- Removed this line.
    }

In the idl_gen_cpp.cpp file itself, I refactored some code generation into
new functions: GenParam, GenNativeTable, GenVerifyCall, GenBuilders,
GenUnpackFieldStatement, and GenCreateParam.

Change-Id: I727b1bd8719d05b7ce33cbce00eb58fda817b25d
2017-01-13 17:44:42 -08:00

159 lines
5.0 KiB
C++

/*
* Copyright 2016 Google Inc. 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.
*/
#include "flatbuffers/code_generators.h"
#include <assert.h>
#include "flatbuffers/util.h"
namespace flatbuffers {
void CodeWriter::operator+=(std::string text) {
while (true) {
auto begin = text.find("{{");
if (begin == std::string::npos) {
break;
}
auto end = text.find("}}");
if (end == std::string::npos || end < begin) {
break;
}
// Write all the text before the first {{ into the stream.
stream_.write(text.c_str(), begin);
// The key is between the {{ and }}.
const std::string key = text.substr(begin + 2, end - begin - 2);
// Find the value associated with the key. If it exists, write the
// value into the stream, otherwise write the key itself into the stream.
auto iter = value_map_.find(key);
if (iter != value_map_.end()) {
const std::string &value = iter->second;
stream_ << value;
} else {
assert(false && "could not find key");
stream_ << key;
}
// Update the text to everything after the }}.
text = text.substr(end + 2);
}
if (!text.empty() && text.back() == '\\') {
text.pop_back();
stream_ << text;
} else {
stream_ << text << std::endl;
}
}
const char *BaseGenerator::FlatBuffersGeneratedWarning() {
return "automatically generated by the FlatBuffers compiler,"
" do not modify\n\n";
}
std::string BaseGenerator::NamespaceDir(const Parser &parser,
const std::string &path,
const Namespace &ns) {
EnsureDirExists(path.c_str());
if (parser.opts.one_file) return path;
std::string namespace_dir = path; // Either empty or ends in separator.
auto &namespaces = ns.components;
for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
namespace_dir += *it + kPathSeparator;
EnsureDirExists(namespace_dir.c_str());
}
return namespace_dir;
}
std::string BaseGenerator::NamespaceDir(const Namespace &ns) const {
return BaseGenerator::NamespaceDir(parser_, path_, ns);
}
bool BaseGenerator::IsEverythingGenerated() const {
for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
++it) {
if (!(*it)->generated) return false;
}
for (auto it = parser_.structs_.vec.begin();
it != parser_.structs_.vec.end(); ++it) {
if (!(*it)->generated) return false;
}
return true;
}
std::string BaseGenerator::FullNamespace(const char *separator,
const Namespace &ns) {
std::string namespace_name;
auto &namespaces = ns.components;
for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
if (namespace_name.length()) namespace_name += separator;
namespace_name += *it;
}
return namespace_name;
}
std::string BaseGenerator::LastNamespacePart(const Namespace &ns) {
if (!ns.components.empty())
return ns.components.back();
else
return std::string("");
}
// Ensure that a type is prefixed with its namespace whenever it is used
// outside of its namespace.
std::string BaseGenerator::WrapInNameSpace(const Namespace *ns,
const std::string &name) const {
if (CurrentNameSpace() == ns) return name;
std::string qualified_name = qualifying_start_;
for (auto it = ns->components.begin(); it != ns->components.end(); ++it)
qualified_name += *it + qualifying_separator_;
return qualified_name + name;
}
std::string BaseGenerator::WrapInNameSpace(const Definition &def) const {
return WrapInNameSpace(def.defined_namespace, def.name);
}
// Generate a documentation comment, if available.
void GenComment(const std::vector<std::string> &dc, std::string *code_ptr,
const CommentConfig *config, const char *prefix) {
if (dc.begin() == dc.end()) {
// Don't output empty comment blocks with 0 lines of comment content.
return;
}
std::string &code = *code_ptr;
if (config != nullptr && config->first_line != nullptr) {
code += std::string(prefix) + std::string(config->first_line) + "\n";
}
std::string line_prefix = std::string(prefix) +
((config != nullptr && config->content_line_prefix != nullptr) ?
config->content_line_prefix : "///");
for (auto it = dc.begin();
it != dc.end();
++it) {
code += line_prefix + *it + "\n";
}
if (config != nullptr && config->last_line != nullptr) {
code += std::string(prefix) + std::string(config->last_line) + "\n";
}
}
} // namespace flatbuffers