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use onError for common error-processing, and a new write which process error by itself #6

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use onError for common error-processing, and a new write which process error by itself #6

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1b0f127
`onError` for common error-processing logic
ImpleLee May 7, 2021
d2fa120
`unsigned` -> `size_t` for array length
ImpleLee May 7, 2021
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65 changes: 36 additions & 29 deletions terminal/src/terminal.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,31 @@
#include <sstream>
#include <cstring>
#include <stdexcept>
#include <string>

namespace {
struct charSpan {
const char *content;
std::size_t len;
charSpan(const char *content, const std::size_t len):
content(content), len(len) {}
template <std::size_t N>
charSpan(const char (&content)[N]): charSpan(content, N) {}
};
void onError(int return_code, const charSpan error_prefix) {
if (return_code < 0) {
std::string error_message{error_prefix.content, error_prefix.len};
error_message += strerror(errno);
throw std::runtime_error(std::move(error_message));
}
}
void write(int term, const charSpan content, const charSpan error_prefix) {
onError(
::write(term, content.content, content.len) != content.len ? -1 : 0,
error_prefix
);
}
}

namespace hacktile {
namespace terminal {
Expand All @@ -31,12 +56,8 @@ initializedTerminal::initializedTerminal(int term):
term(term) {
// Retrieve the original flag of terminal, so that they
// could be recovered once the program has exit.
if(tcgetattr(term, &terminalMode) < 0) {
std::stringstream error;
error << "cannot fetch terminal attribute: "
<< strerror(errno);
throw std::runtime_error(error.str());
}
onError(tcgetattr(term, &terminalMode),
"cannot fetch terminal attribute: ");
}
initializedTerminal::~initializedTerminal() {
// Reset the screen display mode.
Expand All @@ -53,29 +74,19 @@ newTerminal::newTerminal(int term): initializedTerminal(term) {
newTerminalMode.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
newTerminalMode.c_cc[VMIN] = 1;
newTerminalMode.c_cc[VTIME] = 0;
if(tcsetattr(term, TCSANOW, &newTerminalMode) < 0) {
std::stringstream error;
error << "cannot initialize terminal: "
<< strerror(errno);
throw std::runtime_error(error.str());
}
onError(tcsetattr(term, TCSANOW, &newTerminalMode),
"cannot initialize terminal: ");
}

clearScreen::clearScreen(int term): newTerminal(term) {
// Initialize the current screen for printing.
char initScreen[] = control "2J" control "0;0H" control "?25l";
size_t lenInitScreen = sizeof(initScreen);
if(write(term, initScreen, lenInitScreen) != lenInitScreen) {
std::stringstream error;
error << "cannot setup terminal screen: "
<< strerror(errno);
throw std::runtime_error(error.str());
}
write(term, control "2J" control "0;0H" control "?25l",
"cannot setup terminal screen: ");
}
clearScreen::~clearScreen() {
// Clear screen data and reset the pointer.
char resetPointer[] = control "0;0H" control "?25h" control "2J";
write(term, resetPointer, sizeof(resetPointer));
write(term, control "0;0H" control "?25h" control "2J",
"cannot reset pointer: ");
}
}

Expand Down Expand Up @@ -191,13 +202,9 @@ void terminal::append(const char* s, size_t length) {
}

void terminal::flush() {
if(write(term, buffer.data(), buffer.size()) != buffer.size()) {
std::stringstream error;
error << "cannot write to terminal: " << strerror(errno);
throw std::runtime_error(error.str());
} else {
buffer = std::vector<char>();
}
write(term, charSpan{buffer.data(), buffer.size()},
"cannot write to terminal: ");
buffer = std::vector<char>();
}

} // namespace hacktile::terminal
Expand Down