Add (build, clean, run) subcommands for nob

nob.c

@@ -167,37 +167,73 @@ bool build_bootable_image(Nob_Cmd *cmd) {
     return true;
 }
 
+bool runQemu(Nob_Cmd *cmd) {
+    nob_cmd_append(cmd, "qemu-system-i386", "-cdrom", BUILD_FOLDER "kernel.iso");
+    if (!nob_cmd_run(cmd))
+        return false;
+    return true;
+}
+
 int main(int argc, char **argv) {
     NOB_GO_REBUILD_URSELF(argc, argv);
+    const char *program_name = shift(argv, argc);
+    bool clean = false;
+    bool run = false; // starts qemu
+    bool build = false;
+    while (argc > 0) {
+        const char *arg = shift(argv, argc);
+        if (strcmp(arg, "clean") == 0)
+            clean = true;
+        if (strcmp(arg, "run") == 0)
+            run = true;
+        if (strcmp(arg, "build") == 0)
+            build = true;
+    }
 
-    if (argc >= 2) {
-        if (strcmp(argv[1], "clean") == 0) {
+    if (clean) {
+        const char *dir_path = BUILD_FOLDER;
+
+        Nob_Dir_Entry dir = {0};
+        if (!nob_dir_entry_open(dir_path, &dir)) {
+            nob_log(NOB_INFO, "No build directory to clean. Skipping...");
+        } else {
             if (!clean_dir(BUILD_FOLDER))
                 return 1;
-        } else {
-            nob_log(NOB_INFO, "Usage: %s (clean)", argv[0]);
-            return 1;
+            nob_delete_file(BUILD_FOLDER);
         }
     }
 
-    if (!nob_mkdir_if_not_exists(BUILD_FOLDER))
-        return 1;
+    if (build) {
+        if (!nob_mkdir_if_not_exists(BUILD_FOLDER))
+            return 1;
 
-    Nob_Cmd cmd = {0};
+        Nob_Cmd cmd = {0};
 
-    if (!render_clangd_config())
-        return 1;
+        if (!render_clangd_config())
+            return 1;
 
-    if (!build_assembly(&cmd))
-        return 1;
-    if (!build_c(&cmd))
-        return 1;
-    if (!link_everything(&cmd))
-        return 1;
-    if (!check_kernel(&cmd))
-        return 1;
-    if (!build_bootable_image(&cmd))
+        if (!build_assembly(&cmd))
+            return 1;
+        if (!build_c(&cmd))
+            return 1;
+        if (!link_everything(&cmd))
+            return 1;
+        if (!check_kernel(&cmd))
+            return 1;
+        if (!build_bootable_image(&cmd))
+            return 1;
+    }
+
+    if (run) {
+        Nob_Cmd cmd = {0};
+        if (!runQemu(&cmd))
+            return 1;
+    }
+
+    if (!clean && !build && !run) {
+        nob_log(NOB_INFO, "Usage: %s (build || clean || run)", program_name);
         return 1;
+    }
 
     return 0;
 }