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// Copyright 2021 Benjamin Barenblat
//
// 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
//
// https://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.
// Parses and interprets terminfo string capabilities. These are written in a
// simple stack-based programming language whose semantics are documented in
// terminfo(5).
#ifndef EC_GOLDFISHTERM_INTERNAL_STRING_CAPABILITY_H_
#define EC_GOLDFISHTERM_INTERNAL_STRING_CAPABILITY_H_
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "goldfishterm/internal/emit.h"
#include "goldfishterm/terminfo.h"
#include "third_party/abseil/absl/types/optional.h"
#include "third_party/abseil/absl/types/variant.h"
namespace goldfishterm_internal {
using StringCapabilityParameter = absl::variant<int, std::string>;
struct InterpretStringCapabilityInput {
std::string capability;
std::vector<StringCapabilityParameter> parameters;
// The number of lines affected by this operation.
int lines_affected;
// The minimum baud rate at which padding should be expanded.
int padding_baud_rate;
// The padding character, or absl::nullopt if the terminal doesn't support
// padding.
absl::optional<char> pad_char;
// True iff the terminal supports XON/XOFF handshaking.
bool has_xon_xoff;
// The baud rate of the terminal.
int baud;
// The number of extra bits sent per character. For a terminal emulator, this
// is generally 0; for an RS-232 line, it's generally 2 or 3 (one start bit,
// one stop bit, and possibly one parity bit).
int extra_bits_per_character;
// Constructs an InterpretStringCapabilityInput with fail-safe defaults.
explicit InterpretStringCapabilityInput() noexcept
: lines_affected(1),
padding_baud_rate(0),
pad_char('\0'),
has_xon_xoff(false),
baud(9600),
extra_bits_per_character(0) {}
// Constructs an InterpretStringCapabilityInput from a terminfo entry.
explicit InterpretStringCapabilityInput(
const goldfishterm::TerminfoEntry& terminfo, std::string capability_,
std::vector<StringCapabilityParameter> parameters_, int baud_,
int lines_affected_) noexcept
: capability(std::move(capability_)),
parameters(std::move(parameters_)),
lines_affected(lines_affected_),
padding_baud_rate(
terminfo.get(goldfishterm::NumericCapability::kPaddingBaudRate)
.value_or(0)),
pad_char(terminfo.get(goldfishterm::StringCapability::kCharPadding)
.value_or(std::string(1, '\0'))[0]),
has_xon_xoff(terminfo.get(goldfishterm::BooleanCapability::kXonXoff)),
baud(baud_),
extra_bits_per_character(0) {}
};
struct InterpretStringCapabilityResult {
// Terms in the emitter EDSL (see emit.h).
std::vector<std::shared_ptr<const EmitTerm>> terms;
// The expected cost of emitting these terms. This is a unitless, arbitrarily
// scaled real number; it will be at least 0, but you should not rely on any
// absolute semantics.
float cost;
};
// Interprets a terminfo string capability, expanding parameters and inserting
// padding and delays as appropriate. Throws std::runtime_error if parsing or
// interpretation fails.
InterpretStringCapabilityResult InterpretStringCapability(
const InterpretStringCapabilityInput&);
} // namespace goldfishterm_internal
#endif // EC_GOLDFISHTERM_INTERNAL_STRING_CAPABILITY_H_
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