basic IPC working

.gitignore

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+cmake-build-debug
+.idea

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.28)
+project(ipcswaytest)
+
+set(CMAKE_CXX_STANDARD 17)
+
+find_package(nlohmann_json 3.2.0 REQUIRED)
+
+add_executable(ipcswaytest main.cpp
+        sway_bindings/swaymsg.h
+        sway_bindings/Sway.h
+        sway_bindings/Sway.cpp
+        sway_bindings/Formatter.h)
+
+target_link_libraries(ipcswaytest PRIVATE nlohmann_json::nlohmann_json)

main.cpp

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+#include <iostream>
+
+#include "sway_bindings/swaymsg.h"
+#include "sway_bindings/Sway.h"
+
+int main() {
+    auto sway = Sway();
+    auto resp = sway.sendIPC(SWAY_GET_TREE);
+    std::cout << resp.msg << "\n";
+
+    return 0;
+}

sway_bindings/Formatter.h

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+//
+// Created by grimmauld on 03.03.24.
+// https://stackoverflow.com/questions/12261915/how-to-throw-stdexceptions-with-variable-messages
+//
+
+#ifndef IPCSWAYTEST_FORMATTER_H
+#define IPCSWAYTEST_FORMATTER_H
+
+#include <stdexcept>
+#include <sstream>
+
+class Formatter
+{
+public:
+    Formatter() = default;
+    ~Formatter() = default;
+
+    template <typename Type>
+    Formatter & operator << (const Type & value)
+    {
+        stream_ << value;
+        return *this;
+    }
+
+    std::string str() const         { return stream_.str(); }
+    explicit operator std::string () const   { return stream_.str(); }
+
+    enum ConvertToString
+    {
+        to_str
+    };
+    std::string operator >> (ConvertToString) { return stream_.str(); }
+
+    Formatter(const Formatter &) = delete;
+
+private:
+    std::stringstream stream_;
+    // Formatter & operator = (Formatter &);
+};
+
+#endif //IPCSWAYTEST_FORMATTER_H

sway_bindings/Sway.cpp

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+//
+// Created by grimmauld on 03.03.24.
+//
+
+#include "Sway.h"
+
+swaymsg Sway::sendIPC(const swaymsg &query) const {
+    if (send(socketfd, query.asBuffer(), query.size(), 0) == -1) {
+        throw std::runtime_error("Swaysock: Error on send() call");
+    }
+
+    return swaymsg::fromSock(socketfd);
+}
+
+Sway::Sway() : socketfd(socket(AF_UNIX, SOCK_STREAM, 0)) {
+    initializeSocket();
+}
+
+void Sway::initializeSocket() const {
+    auto *sockaddr = std::getenv("SWAYSOCK");
+    if (sockaddr == nullptr) {
+        throw std::runtime_error("Binding socket: reading SWAYSOCK env var failed");
+    }
+
+    if (socketfd == -1) {
+        throw std::runtime_error("Binding socket: could not get file descriptor");
+    }
+
+    struct sockaddr_un swaysock{};
+    swaysock.sun_family = AF_UNIX;
+    strcpy(swaysock.sun_path, sockaddr);
+    auto dlen = strlen(swaysock.sun_path) + sizeof(swaysock.sun_family);
+
+    if (connect(socketfd, (struct sockaddr *) &swaysock, dlen) == -1) {
+        throw std::runtime_error("Binding socket: could not connect to socket");
+    }
+}

sway_bindings/Sway.h

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+//
+// Created by grimmauld on 03.03.24.
+//
+
+#ifndef IPCSWAYTEST_SWAY_H
+#define IPCSWAYTEST_SWAY_H
+
+#include "swaymsg.h"
+
+class Sway {
+protected:
+    const int socketfd;
+
+public:
+    explicit Sway();
+
+    void initializeSocket() const;
+
+    [[nodiscard]] swaymsg sendIPC(const swaymsg& query) const;
+};
+
+
+#endif //IPCSWAYTEST_SWAY_H

sway_bindings/swaymsg.h

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+//
+// Created by grimmauld on 03.03.24.
+//
+
+#ifndef IPCSWAYTEST_SWAYMSG_H
+#define IPCSWAYTEST_SWAYMSG_H
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <cstring>
+#include <cstdlib>
+#include "Formatter.h"
+
+struct swaymsg {
+    explicit swaymsg(const unsigned int payloadType, const char *msg) : swaymsg(payloadType, msg,
+                                                                                msg == nullptr ? 0 : strlen(msg)) {};
+
+    explicit swaymsg(const unsigned int payloadType, const char *msg, const unsigned int payload_len)
+            : payload_len(payload_len), payload_type(payloadType) {
+
+        this->msg = static_cast<char *>(std::malloc(payload_len));
+        std::memcpy(this->msg, msg, payload_len);
+
+        buff = static_cast<unsigned char *>(std::malloc(size()));
+        std::memcpy(buff, magic, strlen(magic));
+        std::memcpy(buff + (unsigned int) strlen(magic), &payload_len, sizeof(payload_len));
+        std::memcpy(buff + (unsigned int) strlen(magic) + sizeof(payload_len), &payload_type, sizeof(payload_type));
+        std::memcpy(buff + (unsigned int) strlen(magic) + sizeof(payload_len) + sizeof(payload_type), msg, payload_len);
+    }
+
+    explicit swaymsg(const unsigned int payloadType) : swaymsg(payloadType, nullptr) {}
+
+    [[nodiscard]] static swaymsg fromSock(const int sockfd) {
+        char buff[6];
+        size_t dlen;
+        if ((dlen = recv(sockfd, buff, 6, 0)) != 6) {
+            throw std::runtime_error(
+                    Formatter() << "Swaysock: Unexpected length on recv() call for magic: " << dlen
+                                >> Formatter::to_str);
+        }
+
+        if (strncmp(buff, magic, 6) != 0) {
+            throw std::runtime_error("Swaysock: magic did not match");
+        }
+
+        unsigned int payloadType;
+        unsigned int payloadLen;
+        static_assert(sizeof(payloadType) == 4);
+        static_assert(sizeof(payloadLen) == 4);
+
+        if ((dlen = recv(sockfd, &payloadLen, sizeof(payloadLen), 0)) != sizeof(payloadLen)) {
+            throw std::runtime_error(
+                    Formatter() << "Swaysock: Unexpected length on recv() call for len: " << dlen >> Formatter::to_str);
+        }
+
+        if ((dlen = recv(sockfd, &payloadType, sizeof(payloadType), 0)) != sizeof(payloadType)) {
+            throw std::runtime_error(
+                    Formatter() << "Swaysock: Unexpected length on recv() call for type: " << dlen
+                                >> Formatter::to_str);
+        }
+
+        char msgBuff[payloadLen];
+        if ((dlen = recv(sockfd, msgBuff, payloadLen, 0)) != payloadLen) {
+            throw std::runtime_error(
+                    Formatter() << "Swaysock: Unexpected length on recv() call for message: " << dlen
+                                >> Formatter::to_str);
+        }
+        return swaymsg(payloadType, msgBuff, payloadLen);
+    };
+
+    constexpr const static char *magic = "i3-ipc";
+    const unsigned int payload_len;
+    const unsigned int payload_type;
+    char *msg;
+    unsigned char *buff = nullptr;
+
+    static_assert(sizeof(payload_len) == 4);
+    static_assert(sizeof(payload_type) == 4);
+
+    [[nodiscard]] size_t size() const {
+        return (int) strlen(magic) + sizeof(payload_len) + sizeof(payload_type) + payload_len;
+    }
+
+    [[nodiscard]] void *asBuffer() const {
+        return buff;
+    }
+
+    ~swaymsg() {
+        delete buff;
+        delete msg;
+    }
+};
+
+static const swaymsg SWAY_EXIT = swaymsg(0, "exit");
+static const swaymsg SWAY_GET_WORKSPACES = swaymsg(1);
+static const swaymsg SWAY_GET_OUTPUTS = swaymsg(3);
+static const swaymsg SWAY_GET_TREE = swaymsg(4);
+static const swaymsg SWAY_GET_VERSION = swaymsg(7);
+static const swaymsg SWAY_GET_CONFIG = swaymsg(9);
+static const swaymsg SWAY_GET_INPUTS = swaymsg(100);
+
+
+#endif //IPCSWAYTEST_SWAYMSG_H