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Clean up the interface of io::Printer.

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This CL kicks any definition longer than three or so lines out of the class
body and defines them out of line. The number of private definitions at the head of the class was getting completely out of control.

Ideally we would not kick Printer::Sub out, since its API is important,
but there's no way to do this while also moving ValueImpl out of the class,
which was taking on a whole lot of space.

Today I learned that an out-of-line template definition can have multiple template <> declarations, which is necessary to be able to utter the signature of those symbols out of line.

PiperOrigin-RevId: 495030857
pull/11271/head
Protobuf Team Bot 2 years ago committed by Copybara-Service
parent 025258525c
commit e4116700b5
2 changed files with 390 additions and 337 deletions
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  1. 27
      src/google/protobuf/io/printer.cc
  2. 700
      src/google/protobuf/io/printer.h

27
src/google/protobuf/io/printer.cc
Unescape View File

@ -77,6 +77,30 @@ absl::optional<T> LookupInFrameStack(
} }
} // namespace } // namespace
struct Printer::Format {
struct Chunk {
// The chunk's text; if this is a variable, it does not include the $...$.
absl::string_view text;
// Whether or not this is a variable name, i.e., a $...$.
bool is_var;
};
struct Line {
// Chunks to emit, split along $ and annotates as to whether it is a
// variable name.
std::vector<Chunk> chunks;
// The indentation for this chunk.
size_t indent;
};
std::vector<Line> lines;
// Whether this is a multiline raw string, according to internal heuristics.
bool is_raw_string = false;
};
Printer::Format Printer::TokenizeFormat(absl::string_view format_string, Printer::Format Printer::TokenizeFormat(absl::string_view format_string,
const PrintOptions& options) { const PrintOptions& options) {
Format format; Format format;
@ -668,7 +692,8 @@ void Printer::PrintImpl(absl::string_view format,
"substitution that resolves to callback cannot contain whitespace"); "substitution that resolves to callback cannot contain whitespace");
range_start = sink_.bytes_written(); range_start = sink_.bytes_written();
(*fnc)(); GOOGLE_ABSL_CHECK((*fnc)())
<< "recursive call encountered while evaluating \"" << var << "\"";
range_end = sink_.bytes_written(); range_end = sink_.bytes_written();
} }

700
src/google/protobuf/io/printer.h
Unescape View File

@ -417,159 +417,7 @@ class PROTOBUF_EXPORT Printer {
int line() { return 0; } int line() { return 0; }
}; };
struct AnnotationRecord { struct AnnotationRecord;
std::vector<int> path;
std::string file_path;
// AnnotationRecord's constructors are *not* marked as explicit,
// specifically so that it is possible to construct a
// map<string, AnnotationRecord> by writing
//
// {{"foo", my_cool_descriptor}, {"bar", "file.proto"}}
template <
typename String,
std::enable_if_t<std::is_convertible<const String&, std::string>::value,
int> = 0>
AnnotationRecord( // NOLINT(google-explicit-constructor)
const String& file_path)
: file_path(file_path) {}
template <typename Desc,
// This SFINAE clause excludes char* from matching this
// constructor.
std::enable_if_t<std::is_class<Desc>::value, int> = 0>
AnnotationRecord(const Desc* desc) // NOLINT(google-explicit-constructor)
: file_path(desc->file()->name()) {
desc->GetLocationPath(&path);
}
};
// Helper type for wrapping a variable substitution expansion result.
template <bool owned>
struct ValueImpl {
private:
template <typename T>
struct IsSubImpl : std::false_type {};
template <bool a>
struct IsSubImpl<ValueImpl<a>> : std::true_type {};
public:
using StringType =
std::conditional_t<owned, std::string, absl::string_view>;
// These callbacks return false if this is a recursive call.
using Callback = std::function<bool()>;
using StringOrCallback = absl::variant<StringType, Callback>;
ValueImpl() = default;
// This is a template to avoid colliding with the copy constructor below.
template <typename Value,
std::enable_if_t<!IsSubImpl<absl::remove_cvref_t<Value>>::value,
int> = 0>
ValueImpl(Value&& value) // NOLINT
: value(ToStringOrCallback(std::forward<Value>(value), Rank2{})) {
if (absl::holds_alternative<Callback>(this->value)) {
consume_after = ";,";
}
}
// Copy ctor/assign allow interconversion of the two template parameters.
template <bool that_owned>
ValueImpl(const ValueImpl<that_owned>& that) { // NOLINT
*this = that;
}
template <bool that_owned>
ValueImpl& operator=(const ValueImpl<that_owned>& that) {
// Cast to void* is required, since this and that may potentially be of
// different types (due to the `that_owned` parameter).
if (static_cast<const void*>(this) == static_cast<const void*>(&that)) {
return *this;
}
using ThatStringType = typename ValueImpl<that_owned>::StringType;
if (auto* str = absl::get_if<ThatStringType>(&that.value)) {
value = StringType(*str);
} else {
value = absl::get<Callback>(that.value);
}
consume_after = that.consume_after;
return *this;
}
const StringType* AsString() const {
return absl::get_if<StringType>(&value);
}
const Callback* AsCallback() const {
return absl::get_if<Callback>(&value);
}
StringOrCallback value;
std::string consume_after;
private:
// go/ranked-overloads
struct Rank0 {};
struct Rank1 : Rank0 {};
struct Rank2 : Rank1 {};
// Dummy template for delayed instantiation, which is required for the
// static assert below to kick in only when this function is called when it
// shouldn't.
//
// This is done to produce a better error message than the "candidate does
// not match" SFINAE errors.
template <typename Cb, typename = decltype(std::declval<Cb&&>()())>
StringOrCallback ToStringOrCallback(Cb&& cb, Rank2) {
return Callback(
[cb = std::forward<Cb>(cb), is_called = false]() mutable -> bool {
if (is_called) {
// Catch whether or not this function is being called recursively.
return false;
}
is_called = true;
cb();
is_called = false;
return true;
});
}
// Separate from the AlphaNum overload to avoid copies when taking strings
// by value when in `owned` mode.
StringOrCallback ToStringOrCallback(StringType s, Rank1) { return s; }
StringOrCallback ToStringOrCallback(const absl::AlphaNum& s, Rank0) {
return StringType(s.Piece());
}
};
using ValueView = ValueImpl</*owned=*/false>;
using Value = ValueImpl</*owned=*/true>;
// Provide a helper to use heterogeneous lookup when it's available.
template <class...>
using void_t = void;
template <typename Map, typename = void>
struct has_heterogeneous_lookup : std::false_type {};
template <typename Map>
struct has_heterogeneous_lookup<Map, void_t<decltype(std::declval<Map>().find(
std::declval<absl::string_view>()))>>
: std::true_type {};
template <typename Map,
std::enable_if_t<has_heterogeneous_lookup<Map>::value, int> = 0>
static absl::string_view ToStringKey(absl::string_view x) {
return x;
}
template <typename Map,
std::enable_if_t<!has_heterogeneous_lookup<Map>::value, int> = 0>
static std::string ToStringKey(absl::string_view x) {
return std::string(x);
}
public: public:
static constexpr char kDefaultVariableDelimiter = '$'; static constexpr char kDefaultVariableDelimiter = '$';
@ -577,42 +425,7 @@ class PROTOBUF_EXPORT Printer {
"PROTOC_CODEGEN_TRACE"; "PROTOC_CODEGEN_TRACE";
// Sink type for constructing substitutions to pass to WithVars() and Emit(). // Sink type for constructing substitutions to pass to WithVars() and Emit().
class Sub { class Sub;
public:
template <typename Value>
Sub(std::string key, Value&& value)
: key_(std::move(key)),
value_(std::forward<Value>(value)),
annotation_(absl::nullopt) {}
// NOTE: This is an overload rather than taking optional<AnnotationRecord>
// with a default argument of nullopt, because we want to pick up
// AnnotationRecord's user-defined conversions. Because going from
// e.g. Descriptor* -> optional<AnnotationRecord> requires two user-defined
// conversions, this does not work.
template <typename Key, typename Value>
Sub(Key&& key, Value&& value, AnnotationRecord annotation)
: key_(std::forward<Key>(key)),
value_(std::forward<Value>(value)),
annotation_(std::move(annotation)) {}
Sub Annotate(AnnotationRecord annotation) && {
annotation_ = std::move(annotation);
return std::move(*this);
}
Sub WithSuffix(std::string sub_suffix) && {
value_.consume_after = std::move(sub_suffix);
return std::move(*this);
}
private:
friend class Printer;
std::string key_;
Value value_;
absl::optional<AnnotationRecord> annotation_;
};
// Options for controlling how the output of a Printer is formatted. // Options for controlling how the output of a Printer is formatted.
struct Options { struct Options {
@ -666,39 +479,18 @@ class PROTOBUF_EXPORT Printer {
// //
// Returns an RAII object that pops the lookup frame. // Returns an RAII object that pops the lookup frame.
template <typename Map> template <typename Map>
auto WithVars(const Map* vars) { auto WithVars(const Map* vars);
var_lookups_.emplace_back(
[vars](absl::string_view var) -> absl::optional<ValueView> {
auto it = vars->find(ToStringKey<Map>(var));
if (it == vars->end()) {
return absl::nullopt;
}
return ValueView(it->second);
});
return absl::MakeCleanup([this] { var_lookups_.pop_back(); });
}
// Pushes a new variable lookup frame that stores `vars` by value. // Pushes a new variable lookup frame that stores `vars` by value.
// //
// When writing `WithVars({...})`, this is the overload that will be called,
// and it will synthesize an `absl::flat_hash_map`.
//
// Returns an RAII object that pops the lookup frame. // Returns an RAII object that pops the lookup frame.
template <typename Map = absl::flat_hash_map<std::string, std::string>, template <typename Map = absl::flat_hash_map<std::string, std::string>,
std::enable_if_t<!std::is_pointer<Map>::value, int> = 0> typename = std::enable_if_t<!std::is_pointer<Map>::value>>
auto WithVars(Map&& vars) { auto WithVars(Map&& vars);
var_lookups_.emplace_back(
[vars = std::forward<Map>(vars)](
absl::string_view var) -> absl::optional<ValueView> {
auto it = vars.find(ToStringKey<Map>(var));
if (it == vars.end()) {
return absl::nullopt;
}
return ValueView(it->second);
});
return absl::MakeCleanup([this] { var_lookups_.pop_back(); });
}
// Pushes a new variable lookup frame that stores `vars` by value.
//
// Returns an RAII object that pops the lookup frame.
auto WithVars(std::initializer_list<Sub> vars); auto WithVars(std::initializer_list<Sub> vars);
// Looks up a variable set with WithVars(). // Looks up a variable set with WithVars().
@ -712,17 +504,7 @@ class PROTOBUF_EXPORT Printer {
// //
// Returns an RAII object that pops the lookup frame. // Returns an RAII object that pops the lookup frame.
template <typename Map> template <typename Map>
auto WithAnnotations(const Map* vars) { auto WithAnnotations(const Map* vars);
annotation_lookups_.emplace_back(
[vars](absl::string_view var) -> absl::optional<AnnotationRecord> {
auto it = vars->find(ToStringKey<Map>(var));
if (it == vars->end()) {
return absl::nullopt;
}
return AnnotationRecord(it->second);
});
return absl::MakeCleanup([this] { annotation_lookups_.pop_back(); });
}
// Pushes a new variable lookup frame that stores `vars` by value. // Pushes a new variable lookup frame that stores `vars` by value.
// //
@ -731,18 +513,7 @@ class PROTOBUF_EXPORT Printer {
// //
// Returns an RAII object that pops the lookup frame. // Returns an RAII object that pops the lookup frame.
template <typename Map = absl::flat_hash_map<std::string, AnnotationRecord>> template <typename Map = absl::flat_hash_map<std::string, AnnotationRecord>>
auto WithAnnotations(Map&& vars) { auto WithAnnotations(Map&& vars);
annotation_lookups_.emplace_back(
[vars = std::forward<Map>(vars)](
absl::string_view var) -> absl::optional<AnnotationRecord> {
auto it = vars.find(ToStringKey<Map>(var));
if (it == vars.end()) {
return absl::nullopt;
}
return AnnotationRecord(it->second);
});
return absl::MakeCleanup([this] { annotation_lookups_.pop_back(); });
}
// Increases the indentation by `indent` spaces; when nullopt, increments // Increases the indentation by `indent` spaces; when nullopt, increments
// indentation by the configured default spaces_per_indent. // indentation by the configured default spaces_per_indent.
@ -759,9 +530,7 @@ class PROTOBUF_EXPORT Printer {
// //
// `format` MUST be a string constant. // `format` MUST be a string constant.
void Emit(absl::string_view format, void Emit(absl::string_view format,
SourceLocation loc = SourceLocation::current()) { SourceLocation loc = SourceLocation::current());
Emit({}, format, loc);
}
// Emits formatted source code to the underlying output, injecting // Emits formatted source code to the underlying output, injecting
// additional variables as a lookup frame for just this call. See the class // additional variables as a lookup frame for just this call. See the class
@ -788,31 +557,10 @@ class PROTOBUF_EXPORT Printer {
// TODO(b/242326974): Deprecate these APIs. // TODO(b/242326974): Deprecate these APIs.
template <typename Map = absl::flat_hash_map<std::string, std::string>> template <typename Map = absl::flat_hash_map<std::string, std::string>>
void Print(const Map& vars, absl::string_view text) { void Print(const Map& vars, absl::string_view text);
PrintOptions opts;
opts.checks_are_debug_only = true;
opts.use_substitution_map = true;
opts.allow_digit_substitutions = false;
auto pop = WithVars(&vars);
PrintImpl(text, {}, opts);
}
template <typename... Args> template <typename... Args>
void Print(absl::string_view text, const Args&... args) { void Print(absl::string_view text, const Args&... args);
static_assert(sizeof...(args) % 2 == 0, "");
// Include an extra arg, since a zero-length array is ill-formed, and
// MSVC complains.
absl::string_view vars[] = {args..., ""};
absl::flat_hash_map<absl::string_view, absl::string_view> map;
map.reserve(sizeof...(args) / 2);
for (size_t i = 0; i < sizeof...(args); i += 2) {
map.emplace(vars[i], vars[i + 1]);
}
Print(map, text);
}
// Link a substitution variable emitted by the last call to Print to the // Link a substitution variable emitted by the last call to Print to the
// object described by descriptor. // object described by descriptor.
@ -825,17 +573,9 @@ class PROTOBUF_EXPORT Printer {
// the last call to Print to the object described by descriptor. The range // the last call to Print to the object described by descriptor. The range
// begins at begin_varname's value and ends after the last character of the // begins at begin_varname's value and ends after the last character of the
// value substituted for end_varname. // value substituted for end_varname.
template <typename SomeDescriptor> template <typename Desc>
void Annotate(absl::string_view begin_varname, absl::string_view end_varname, void Annotate(absl::string_view begin_varname, absl::string_view end_varname,
const SomeDescriptor* descriptor) { const Desc* descriptor);
if (options_.annotation_collector == nullptr) {
return;
}
std::vector<int> path;
descriptor->GetLocationPath(&path);
Annotate(begin_varname, end_varname, descriptor->file()->name(), path);
}
// Link a substitution variable emitted by the last call to Print to the file // Link a substitution variable emitted by the last call to Print to the file
// with path file_name. // with path file_name.
@ -866,75 +606,41 @@ class PROTOBUF_EXPORT Printer {
// compiler::cpp::Formatter instead. // compiler::cpp::Formatter instead.
template <typename Map = absl::flat_hash_map<std::string, std::string>> template <typename Map = absl::flat_hash_map<std::string, std::string>>
void FormatInternal(absl::Span<const std::string> args, const Map& vars, void FormatInternal(absl::Span<const std::string> args, const Map& vars,
absl::string_view format) { absl::string_view format);
PrintOptions opts;
opts.use_curly_brace_substitutions = true;
opts.strip_spaces_around_vars = true;
auto pop = WithVars(&vars);
PrintImpl(format, args, opts);
}
private: private:
// Options for PrintImpl(). struct PrintOptions;
struct PrintOptions { struct Format;
// The callsite of the public entry-point. Only Emit() sets this.
absl::optional<SourceLocation> loc;
// If set, Validate() calls will not crash the program.
bool checks_are_debug_only = false;
// If set, the `substitutions_` map will be populated as variables are
// substituted.
bool use_substitution_map = false;
// If set, the ${1$ and $}$ forms will be substituted. These are used for
// a slightly janky annotation-insertion mechanism in FormatInternal, that
// requires that passed-in substitution variables be serialized protos.
bool use_curly_brace_substitutions = false;
// If set, the $n$ forms will be substituted, pulling from the `args`
// argument to PrintImpl().
bool allow_digit_substitutions = true;
// If set, when a variable substitution with spaces in it, such as $ var$,
// is encountered, the spaces are stripped, so that it is as if it was
// $var$. If $var$ substitutes to a non-empty string, the removed spaces are
// printed around the substituted value.
//
// See the class documentation for more information on this behavior.
bool strip_spaces_around_vars = true;
// If set, leading whitespace will be stripped from the format string to
// determine the "extraneous indentation" that is produced when the format
// string is a C++ raw string. This is used to remove leading spaces from
// a raw string that would otherwise result in erratic indentation in the
// output.
bool strip_raw_string_indentation = false;
// If set, the annotation lookup frames are searched, per the annotation
// semantics of Emit() described in the class documentation.
bool use_annotation_frames = true;
};
friend class FormatIterator;
struct Format { // Helper type for wrapping a variable substitution expansion result.
struct Chunk { template <bool owned>
// The chunk's text; if this is a variable, it does not include the $...$. struct ValueImpl;
absl::string_view text;
// Whether or not this is a variable name, i.e., a $...$. using ValueView = ValueImpl</*owned=*/false>;
bool is_var; using Value = ValueImpl</*owned=*/true>;
};
struct Line { // Provide a helper to use heterogeneous lookup when it's available.
// Chunks to emit, split along $ and annotates as to whether it is a template <typename...>
// variable name. using Void = void;
std::vector<Chunk> chunks;
// The indentation for this chunk. template <typename Map, typename = void>
size_t indent; struct HasHeteroLookup : std::false_type {};
}; template <typename Map>
struct HasHeteroLookup<Map, Void<decltype(std::declval<Map>().find(
std::declval<absl::string_view>()))>>
: std::true_type {};
std::vector<Line> lines; template <typename Map,
typename = std::enable_if_t<HasHeteroLookup<Map>::value>>
static absl::string_view ToStringKey(absl::string_view x) {
return x;
}
// Whether this is a multiline raw string, according to internal heuristics. template <typename Map,
bool is_raw_string = false; typename = std::enable_if_t<!HasHeteroLookup<Map>::value>>
}; static std::string ToStringKey(absl::string_view x) {
return std::string(x);
}
Format TokenizeFormat(absl::string_view format_string, Format TokenizeFormat(absl::string_view format_string,
const PrintOptions& options); const PrintOptions& options);
@ -1006,6 +712,328 @@ class PROTOBUF_EXPORT Printer {
std::vector<std::string> line_start_variables_; std::vector<std::string> line_start_variables_;
}; };
// Options for PrintImpl().
struct Printer::PrintOptions {
// The callsite of the public entry-point. Only Emit() sets this.
absl::optional<SourceLocation> loc;
// If set, Validate() calls will not crash the program.
bool checks_are_debug_only = false;
// If set, the `substitutions_` map will be populated as variables are
// substituted.
bool use_substitution_map = false;
// If set, the ${1$ and $}$ forms will be substituted. These are used for
// a slightly janky annotation-insertion mechanism in FormatInternal, that
// requires that passed-in substitution variables be serialized protos.
bool use_curly_brace_substitutions = false;
// If set, the $n$ forms will be substituted, pulling from the `args`
// argument to PrintImpl().
bool allow_digit_substitutions = true;
// If set, when a variable substitution with spaces in it, such as $ var$,
// is encountered, the spaces are stripped, so that it is as if it was
// $var$. If $var$ substitutes to a non-empty string, the removed spaces are
// printed around the substituted value.
//
// See the class documentation for more information on this behavior.
bool strip_spaces_around_vars = true;
// If set, leading whitespace will be stripped from the format string to
// determine the "extraneous indentation" that is produced when the format
// string is a C++ raw string. This is used to remove leading spaces from
// a raw string that would otherwise result in erratic indentation in the
// output.
bool strip_raw_string_indentation = false;
// If set, the annotation lookup frames are searched, per the annotation
// semantics of Emit() described in the class documentation.
bool use_annotation_frames = true;
};
// Helper type for wrapping a variable substitution expansion result.
template <bool owned>
struct Printer::ValueImpl {
private:
template <typename T>
struct IsSubImpl : std::false_type {};
template <bool a>
struct IsSubImpl<ValueImpl<a>> : std::true_type {};
public:
using StringType = std::conditional_t<owned, std::string, absl::string_view>;
// These callbacks return false if this is a recursive call.
using Callback = std::function<bool()>;
using StringOrCallback = absl::variant<StringType, Callback>;
ValueImpl() = default;
// This is a template to avoid colliding with the copy constructor below.
template <typename Value,
typename = std::enable_if_t<
!IsSubImpl<absl::remove_cvref_t<Value>>::value>>
ValueImpl(Value&& value) // NOLINT
: value(ToStringOrCallback(std::forward<Value>(value), Rank2{})) {
if (absl::holds_alternative<Callback>(this->value)) {
consume_after = ";,";
}
}
// Copy ctor/assign allow interconversion of the two template parameters.
template <bool that_owned>
ValueImpl(const ValueImpl<that_owned>& that) { // NOLINT
*this = that;
}
template <bool that_owned>
ValueImpl& operator=(const ValueImpl<that_owned>& that);
const StringType* AsString() const {
return absl::get_if<StringType>(&value);
}
const Callback* AsCallback() const { return absl::get_if<Callback>(&value); }
StringOrCallback value;
std::string consume_after;
private:
// go/ranked-overloads
struct Rank0 {};
struct Rank1 : Rank0 {};
struct Rank2 : Rank1 {};
// Dummy template for delayed instantiation, which is required for the
// static assert below to kick in only when this function is called when it
// shouldn't.
//
// This is done to produce a better error message than the "candidate does
// not match" SFINAE errors.
template <typename Cb, typename = decltype(std::declval<Cb&&>()())>
StringOrCallback ToStringOrCallback(Cb&& cb, Rank2);
// Separate from the AlphaNum overload to avoid copies when taking strings
// by value when in `owned` mode.
StringOrCallback ToStringOrCallback(StringType s, Rank1) { return s; }
StringOrCallback ToStringOrCallback(const absl::AlphaNum& s, Rank0) {
return StringType(s.Piece());
}
};
template <bool owned>
template <bool that_owned>
Printer::ValueImpl<owned>& Printer::ValueImpl<owned>::operator=(
const ValueImpl<that_owned>& that) {
// Cast to void* is required, since this and that may potentially be of
// different types (due to the `that_owned` parameter).
if (static_cast<const void*>(this) == static_cast<const void*>(&that)) {
return *this;
}
using ThatStringType = typename ValueImpl<that_owned>::StringType;
if (auto* str = absl::get_if<ThatStringType>(&that.value)) {
value = StringType(*str);
} else {
value = absl::get<Callback>(that.value);
}
consume_after = that.consume_after;
return *this;
}
template <bool owned>
template <typename Cb, typename /*Sfinae*/>
auto Printer::ValueImpl<owned>::ToStringOrCallback(Cb&& cb, Rank2)
-> StringOrCallback {
return Callback(
[cb = std::forward<Cb>(cb), is_called = false]() mutable -> bool {
if (is_called) {
// Catch whether or not this function is being called recursively.
return false;
}
is_called = true;
cb();
is_called = false;
return true;
});
}
struct Printer::AnnotationRecord {
std::vector<int> path;
std::string file_path;
// AnnotationRecord's constructors are *not* marked as explicit,
// specifically so that it is possible to construct a
// map<string, AnnotationRecord> by writing
//
// {{"foo", my_cool_descriptor}, {"bar", "file.proto"}}
template <
typename String,
std::enable_if_t<std::is_convertible<const String&, std::string>::value,
int> = 0>
AnnotationRecord( // NOLINT(google-explicit-constructor)
const String& file_path)
: file_path(file_path) {}
template <typename Desc,
// This SFINAE clause excludes char* from matching this
// constructor.
std::enable_if_t<std::is_class<Desc>::value, int> = 0>
AnnotationRecord(const Desc* desc) // NOLINT(google-explicit-constructor)
: file_path(desc->file()->name()) {
desc->GetLocationPath(&path);
}
};
class Printer::Sub {
public:
template <typename Value>
Sub(std::string key, Value&& value)
: key_(std::move(key)),
value_(std::forward<Value>(value)),
annotation_(absl::nullopt) {}
// NOTE: This is an overload rather than taking optional<AnnotationRecord>
// with a default argument of nullopt, because we want to pick up
// AnnotationRecord's user-defined conversions. Because going from
// e.g. Descriptor* -> optional<AnnotationRecord> requires two user-defined
// conversions, this does not work.
template <typename Key, typename Value>
Sub(Key&& key, Value&& value, AnnotationRecord annotation)
: key_(std::forward<Key>(key)),
value_(std::forward<Value>(value)),
annotation_(std::move(annotation)) {}
Sub Annotate(AnnotationRecord annotation) && {
annotation_ = std::move(annotation);
return std::move(*this);
}
Sub WithSuffix(std::string sub_suffix) && {
value_.consume_after = std::move(sub_suffix);
return std::move(*this);
}
private:
friend class Printer;
std::string key_;
Value value_;
absl::optional<AnnotationRecord> annotation_;
};
template <typename Map>
auto Printer::WithVars(const Map* vars) {
var_lookups_.emplace_back(
[vars](absl::string_view var) -> absl::optional<ValueView> {
auto it = vars->find(ToStringKey<Map>(var));
if (it == vars->end()) {
return absl::nullopt;
}
return ValueView(it->second);
});
return absl::MakeCleanup([this] { var_lookups_.pop_back(); });
}
template <typename Map, typename /*Sfinae*/>
auto Printer::WithVars(Map&& vars) {
var_lookups_.emplace_back(
[vars = std::forward<Map>(vars)](
absl::string_view var) -> absl::optional<ValueView> {
auto it = vars.find(ToStringKey<Map>(var));
if (it == vars.end()) {
return absl::nullopt;
}
return ValueView(it->second);
});
return absl::MakeCleanup([this] { var_lookups_.pop_back(); });
}
template <typename Map>
auto Printer::WithAnnotations(const Map* vars) {
annotation_lookups_.emplace_back(
[vars](absl::string_view var) -> absl::optional<AnnotationRecord> {
auto it = vars->find(ToStringKey<Map>(var));
if (it == vars->end()) {
return absl::nullopt;
}
return AnnotationRecord(it->second);
});
return absl::MakeCleanup([this] { annotation_lookups_.pop_back(); });
}
template <typename Map>
auto Printer::WithAnnotations(Map&& vars) {
annotation_lookups_.emplace_back(
[vars = std::forward<Map>(vars)](
absl::string_view var) -> absl::optional<AnnotationRecord> {
auto it = vars.find(ToStringKey<Map>(var));
if (it == vars.end()) {
return absl::nullopt;
}
return AnnotationRecord(it->second);
});
return absl::MakeCleanup([this] { annotation_lookups_.pop_back(); });
}
// In GCC older than GCC 9, this code (which constructs an empty
// std::initializer_list<Sub>) incorrectly fails to compile if it does not
// follow the definition of the type Sub; this is the only reason it is
// out-of-line.
//
// See https://godbolt.org/z/e4KnM3PE7.
inline void Printer::Emit(absl::string_view format, SourceLocation loc) {
Emit({}, format, loc);
}
template <typename Map>
void Printer::Print(const Map& vars, absl::string_view text) {
PrintOptions opts;
opts.checks_are_debug_only = true;
opts.use_substitution_map = true;
opts.allow_digit_substitutions = false;
auto pop = WithVars(&vars);
PrintImpl(text, {}, opts);
}
template <typename... Args>
void Printer::Print(absl::string_view text, const Args&... args) {
static_assert(sizeof...(args) % 2 == 0, "");
// Include an extra arg, since a zero-length array is ill-formed, and
// MSVC complains.
absl::string_view vars[] = {args..., ""};
absl::flat_hash_map<absl::string_view, absl::string_view> map;
map.reserve(sizeof...(args) / 2);
for (size_t i = 0; i < sizeof...(args); i += 2) {
map.emplace(vars[i], vars[i + 1]);
}
Print(map, text);
}
template <typename Desc>
void Printer::Annotate(absl::string_view begin_varname,
absl::string_view end_varname, const Desc* descriptor) {
if (options_.annotation_collector == nullptr) {
return;
}
std::vector<int> path;
descriptor->GetLocationPath(&path);
Annotate(begin_varname, end_varname, descriptor->file()->name(), path);
}
template <typename Map>
void Printer::FormatInternal(absl::Span<const std::string> args,
const Map& vars, absl::string_view format) {
PrintOptions opts;
opts.use_curly_brace_substitutions = true;
opts.strip_spaces_around_vars = true;
auto pop = WithVars(&vars);
PrintImpl(format, args, opts);
}
inline auto Printer::WithDefs(std::initializer_list<Sub> vars, inline auto Printer::WithDefs(std::initializer_list<Sub> vars,
bool allow_callbacks) { bool allow_callbacks) {
absl::flat_hash_map<std::string, Value> var_map; absl::flat_hash_map<std::string, Value> var_map;

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