Start on rpc, open existing instances ui when trying to launch gsr-ui a second time

src/Rpc.cpp

@@ -0,0 +1,133 @@
+#include "../include/Rpc.hpp"
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <limits.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/fcntl.h>
+
+namespace gsr {
+    static void get_runtime_filepath(char *buffer, size_t buffer_size, const char *filename) {
+        char dir[PATH_MAX];
+
+        const char *runtime_dir = getenv("XDG_RUNTIME_DIR");
+        if(runtime_dir)
+            snprintf(dir, sizeof(dir), "%s", runtime_dir);
+        else
+            snprintf(dir, sizeof(dir), "/run/user/%d", geteuid());
+
+        if(access(dir, F_OK) != 0)
+            snprintf(dir, sizeof(dir), "/tmp");
+
+        snprintf(buffer, buffer_size, "%s/%s", dir, filename);
+    }
+
+    Rpc::~Rpc() {
+        if(fd > 0)
+            close(fd);
+
+        if(file)
+            fclose(file);
+
+        if(!fifo_filepath.empty())
+            remove(fifo_filepath.c_str());
+    }
+
+    bool Rpc::create(const char *name) {
+        if(file) {
+            fprintf(stderr, "Error: Rpc::create: already created/opened\n");
+            return false;
+        }
+
+        char fifo_filepath_tmp[PATH_MAX];
+        get_runtime_filepath(fifo_filepath_tmp, sizeof(fifo_filepath_tmp), name);
+        fifo_filepath = fifo_filepath_tmp;
+        remove(fifo_filepath.c_str());
+
+        if(mkfifo(fifo_filepath.c_str(), 0600) != 0) {
+            fprintf(stderr, "Error: mkfifo failed, error: %s, %s\n", strerror(errno), fifo_filepath.c_str());
+            return false;
+        }
+
+        if(!open_filepath(fifo_filepath.c_str())) {
+            remove(fifo_filepath.c_str());
+            fifo_filepath.clear();
+            return false;
+        }
+
+        return true;
+    }
+
+    bool Rpc::open(const char *name) {
+        if(file) {
+            fprintf(stderr, "Error: Rpc::open: already created/opened\n");
+            return false;
+        }
+
+        char fifo_filepath_tmp[PATH_MAX];
+        get_runtime_filepath(fifo_filepath_tmp, sizeof(fifo_filepath_tmp), name);
+        return open_filepath(fifo_filepath_tmp);
+    }
+
+    bool Rpc::open_filepath(const char *filepath) {
+        fd = ::open(filepath, O_RDWR | O_NONBLOCK);
+        if(fd <= 0)
+            return false;
+
+        file = fdopen(fd, "r+");
+        if(!file) {
+            close(fd);
+            fd = 0;
+            return false;
+        }
+        fd = 0;
+        return true;
+    }
+
+    bool Rpc::write(const char *str, size_t size) {
+        if(!file) {
+            fprintf(stderr, "Error: Rpc::write: fifo not created/opened yet\n");
+            return false;
+        }
+
+        ssize_t offset = 0;
+        while(offset < (ssize_t)size) {
+            const ssize_t bytes_written = fwrite(str + offset, 1, size - offset, file);
+            fflush(file);
+            if(bytes_written > 0)
+                offset += bytes_written;
+        }
+        return true;
+    }
+
+    void Rpc::poll() {
+        if(!file) {
+            //fprintf(stderr, "Error: Rpc::poll: fifo not created/opened yet\n");
+            return;
+        }
+
+        std::string name;
+        char line[1024];
+        while(fgets(line, sizeof(line), file)) {
+            int line_len = strlen(line);
+            if(line_len == 0)
+                continue;
+
+            if(line[line_len - 1] == '\n') {
+                line[line_len - 1] = '\0';
+                --line_len;
+            }
+
+            name = line;
+            auto it = handlers_by_name.find(name);
+            if(it != handlers_by_name.end())
+                it->second(name);
+        }
+    }
+
+    bool Rpc::add_handler(const std::string &name, RpcCallback callback) {
+        return handlers_by_name.insert(std::make_pair(name, std::move(callback))).second;
+    }
+}