doc: add code samples from uvbook (unadapted)

PR-URL: libuv#1246
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

Author: saghul

docs/code/cgi/main.c

@@ -0,0 +1,81 @@
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <uv.h>
+
+uv_loop_t *loop;
+uv_process_t child_req;
+uv_process_options_t options;
+
+void cleanup_handles(uv_process_t *req, int64_t exit_status, int term_signal) {
+    fprintf(stderr, "Process exited with status %" PRId64 ", signal %d\n", exit_status, term_signal);
+    uv_close((uv_handle_t*) req->data, NULL);
+    uv_close((uv_handle_t*) req, NULL);
+}
+
+void invoke_cgi_script(uv_tcp_t *client) {
+    size_t size = 500;
+    char path[size];
+    uv_exepath(path, &size);
+    strcpy(path + (strlen(path) - strlen("cgi")), "tick");
+
+    char* args[2];
+    args[0] = path;
+    args[1] = NULL;
+
+    /* ... finding the executable path and setting up arguments ... */
+
+    options.stdio_count = 3;
+    uv_stdio_container_t child_stdio[3];
+    child_stdio[0].flags = UV_IGNORE;
+    child_stdio[1].flags = UV_INHERIT_STREAM;
+    child_stdio[1].data.stream = (uv_stream_t*) client;
+    child_stdio[2].flags = UV_IGNORE;
+    options.stdio = child_stdio;
+
+    options.exit_cb = cleanup_handles;
+    options.file = args[0];
+    options.args = args;
+
+    // Set this so we can close the socket after the child process exits.
+    child_req.data = (void*) client;
+    int r;
+    if ((r = uv_spawn(loop, &child_req, &options))) {
+        fprintf(stderr, "%s\n", uv_strerror(r));
+        return;
+    }
+}
+
+void on_new_connection(uv_stream_t *server, int status) {
+    if (status == -1) {
+        // error!
+        return;
+    }
+
+    uv_tcp_t *client = (uv_tcp_t*) malloc(sizeof(uv_tcp_t));
+    uv_tcp_init(loop, client);
+    if (uv_accept(server, (uv_stream_t*) client) == 0) {
+        invoke_cgi_script(client);
+    }
+    else {
+        uv_close((uv_handle_t*) client, NULL);
+    }
+}
+
+int main() {
+    loop = uv_default_loop();
+
+    uv_tcp_t server;
+    uv_tcp_init(loop, &server);
+
+    struct sockaddr_in bind_addr;
+    uv_ip4_addr("0.0.0.0", 7000, &bind_addr);
+    uv_tcp_bind(&server, (const struct sockaddr *)&bind_addr, 0);
+    int r = uv_listen((uv_stream_t*) &server, 128, on_new_connection);
+    if (r) {
+        fprintf(stderr, "Listen error %s\n", uv_err_name(r));
+        return 1;
+    }
+    return uv_run(loop, UV_RUN_DEFAULT);
+}

docs/code/cgi/tick.c

@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main() {
+    int i;
+    for (i = 0; i < 10; i++) {
+        printf("tick\n");
+        fflush(stdout);
+        sleep(1);
+    }
+    printf("BOOM!\n");
+    return 0;
+}

docs/code/detach/main.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+
+#include <uv.h>
+
+uv_loop_t *loop;
+uv_process_t child_req;
+uv_process_options_t options;
+
+int main() {
+    loop = uv_default_loop();
+
+    char* args[3];
+    args[0] = "sleep";
+    args[1] = "100";
+    args[2] = NULL;
+
+    options.exit_cb = NULL;
+    options.file = "sleep";
+    options.args = args;
+    options.flags = UV_PROCESS_DETACHED;
+
+    int r;
+    if ((r = uv_spawn(loop, &child_req, &options))) {
+        fprintf(stderr, "%s\n", uv_strerror(r));
+        return 1;
+    }
+    fprintf(stderr, "Launched sleep with PID %d\n", child_req.pid);
+    uv_unref((uv_handle_t*) &child_req);
+
+    return uv_run(loop, UV_RUN_DEFAULT);
+}

docs/code/dns/main.c

@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <uv.h>
+
+uv_loop_t *loop;
+
+void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
+  buf->base = malloc(suggested_size);
+  buf->len = suggested_size;
+}
+
+void on_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf) {
+    if (nread < 0) {
+        if (nread != UV_EOF)
+            fprintf(stderr, "Read error %s\n", uv_err_name(nread));
+        uv_close((uv_handle_t*) client, NULL);
+        free(buf->base);
+        free(client);
+        return;
+    }
+
+    char *data = (char*) malloc(sizeof(char) * (nread+1));
+    data[nread] = '\0';
+    strncpy(data, buf->base, nread);
+
+    fprintf(stderr, "%s", data);
+    free(data);
+    free(buf->base);
+}
+
+void on_connect(uv_connect_t *req, int status) {
+    if (status < 0) {
+        fprintf(stderr, "connect failed error %s\n", uv_err_name(status));
+        free(req);
+        return;
+    }
+
+    uv_read_start((uv_stream_t*) req->handle, alloc_buffer, on_read);
+    free(req);
+}
+
+void on_resolved(uv_getaddrinfo_t *resolver, int status, struct addrinfo *res) {
+    if (status < 0) {
+        fprintf(stderr, "getaddrinfo callback error %s\n", uv_err_name(status));
+        return;
+    }
+
+    char addr[17] = {'\0'};
+    uv_ip4_name((struct sockaddr_in*) res->ai_addr, addr, 16);
+    fprintf(stderr, "%s\n", addr);
+
+    uv_connect_t *connect_req = (uv_connect_t*) malloc(sizeof(uv_connect_t));
+    uv_tcp_t *socket = (uv_tcp_t*) malloc(sizeof(uv_tcp_t));
+    uv_tcp_init(loop, socket);
+
+    uv_tcp_connect(connect_req, socket, (const struct sockaddr*) res->ai_addr, on_connect);
+
+    uv_freeaddrinfo(res);
+}
+
+int main() {
+    loop = uv_default_loop();
+
+    struct addrinfo hints;
+    hints.ai_family = PF_INET;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_protocol = IPPROTO_TCP;
+    hints.ai_flags = 0;
+
+    uv_getaddrinfo_t resolver;
+    fprintf(stderr, "irc.freenode.net is... ");
+    int r = uv_getaddrinfo(loop, &resolver, on_resolved, "irc.freenode.net", "6667", &hints);
+
+    if (r) {
+        fprintf(stderr, "getaddrinfo call error %s\n", uv_err_name(r));
+        return 1;
+    }
+    return uv_run(loop, UV_RUN_DEFAULT);
+}

docs/code/helloworld/main.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <uv.h>
+
+int main() {
+    uv_loop_t *loop = malloc(sizeof(uv_loop_t));
+    uv_loop_init(loop);
+
+    printf("Now quitting.\n");
+    uv_run(loop, UV_RUN_DEFAULT);
+
+    uv_loop_close(loop);
+    free(loop);
+    return 0;
+}

docs/code/idle-basic/main.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <uv.h>
+
+int64_t counter = 0;
+
+void wait_for_a_while(uv_idle_t* handle) {
+    counter++;
+
+    if (counter >= 10e6)
+        uv_idle_stop(handle);
+}
+
+int main() {
+    uv_idle_t idler;
+
+    uv_idle_init(uv_default_loop(), &idler);
+    uv_idle_start(&idler, wait_for_a_while);
+
+    printf("Idling...\n");
+    uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+
+    uv_loop_close(uv_default_loop());
+    return 0;
+}

docs/code/idle-compute/main.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+
+#include <uv.h>
+
+uv_loop_t *loop;
+uv_fs_t stdin_watcher;
+uv_idle_t idler;
+char buffer[1024];
+
+void crunch_away(uv_idle_t* handle) {
+    // Compute extra-terrestrial life
+    // fold proteins
+    // computer another digit of PI
+    // or similar
+    fprintf(stderr, "Computing PI...\n");
+    // just to avoid overwhelming your terminal emulator
+    uv_idle_stop(handle);
+}
+
+void on_type(uv_fs_t *req) {
+    if (stdin_watcher.result > 0) {
+        buffer[stdin_watcher.result] = '\0';
+        printf("Typed %s\n", buffer);
+
+        uv_buf_t buf = uv_buf_init(buffer, 1024);
+        uv_fs_read(loop, &stdin_watcher, 0, &buf, 1, -1, on_type);
+        uv_idle_start(&idler, crunch_away);
+    }
+    else if (stdin_watcher.result < 0) {
+        fprintf(stderr, "error opening file: %s\n", uv_strerror(req->result));
+    }
+}
+
+int main() {
+    loop = uv_default_loop();
+
+    uv_idle_init(loop, &idler);
+
+    uv_buf_t buf = uv_buf_init(buffer, 1024);
+    uv_fs_read(loop, &stdin_watcher, 0, &buf, 1, -1, on_type);
+    uv_idle_start(&idler, crunch_away);
+    return uv_run(loop, UV_RUN_DEFAULT);
+}

docs/code/interfaces/main.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <uv.h>
+
+int main() {
+    char buf[512];
+    uv_interface_address_t *info;
+    int count, i;
+
+    uv_interface_addresses(&info, &count);
+    i = count;
+
+    printf("Number of interfaces: %d\n", count);
+    while (i--) {
+        uv_interface_address_t interface = info[i];
+
+        printf("Name: %s\n", interface.name);
+        printf("Internal? %s\n", interface.is_internal ? "Yes" : "No");
+        
+        if (interface.address.address4.sin_family == AF_INET) {
+            uv_ip4_name(&interface.address.address4, buf, sizeof(buf));
+            printf("IPv4 address: %s\n", buf);
+        }
+        else if (interface.address.address4.sin_family == AF_INET6) {
+            uv_ip6_name(&interface.address.address6, buf, sizeof(buf));
+            printf("IPv6 address: %s\n", buf);
+        }
+
+        printf("\n");
+    }
+
+    uv_free_interface_addresses(info, count);
+    return 0;
+}

docs/code/locks/main.c

@@ -0,0 +1,57 @@
+#include <stdio.h>
+#include <uv.h>
+
+uv_barrier_t blocker;
+uv_rwlock_t numlock;
+int shared_num;
+
+void reader(void *n)
+{
+    int num = *(int *)n;
+    int i;
+    for (i = 0; i < 20; i++) {
+        uv_rwlock_rdlock(&numlock);
+        printf("Reader %d: acquired lock\n", num);
+        printf("Reader %d: shared num = %d\n", num, shared_num);
+        uv_rwlock_rdunlock(&numlock);
+        printf("Reader %d: released lock\n", num);
+    }
+    uv_barrier_wait(&blocker);
+}
+
+void writer(void *n)
+{
+    int num = *(int *)n;
+    int i;
+    for (i = 0; i < 20; i++) {
+        uv_rwlock_wrlock(&numlock);
+        printf("Writer %d: acquired lock\n", num);
+        shared_num++;
+        printf("Writer %d: incremented shared num = %d\n", num, shared_num);
+        uv_rwlock_wrunlock(&numlock);
+        printf("Writer %d: released lock\n", num);
+    }
+    uv_barrier_wait(&blocker);
+}
+
+int main()
+{
+    uv_barrier_init(&blocker, 4);
+
+    shared_num = 0;
+    uv_rwlock_init(&numlock);
+
+    uv_thread_t threads[3];
+
+    int thread_nums[] = {1, 2, 1};
+    uv_thread_create(&threads[0], reader, &thread_nums[0]);
+    uv_thread_create(&threads[1], reader, &thread_nums[1]);
+
+    uv_thread_create(&threads[2], writer, &thread_nums[2]);
+
+    uv_barrier_wait(&blocker);
+    uv_barrier_destroy(&blocker);
+
+    uv_rwlock_destroy(&numlock);
+    return 0;
+}