1 files changed, 66 insertions, 0 deletions
diff --git a/build.c b/build.c
new file mode 100644
index 0000000..f4b60ff
--- /dev/null
+++ b/build.c
@@ -0,0 +1,66 @@
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <time.h>
+#include <string.h>
+
+#define CC "gcc", "-O3"
+
+int status;
+
+#define RUN_CMD(...) do { \
+  if (fork() == 0) { \
+    char* args[] = __VA_ARGS__; \
+    print_cmd(args); \
+    execvp(args[0], args); \
+    return 0; \
+  } else { \
+    wait(&status); \
+  } \
+} while (0);
+
+void print_cmd(char** args) {
+  int i = 0;
+  while (args[i] != NULL) {
+    printf("%s ", args[i++]);
+  }
+  printf("\n");
+}
+
+
+// https://github.com/tsoding/nob.h/blob/0a08926d8094fc4ae678155c5d73ae21d1f96f3f/nob.h#L2413
+int needs_rebuild(char* bin_file, char* source_file) {
+  struct stat statbuf = {0};
+  if (stat(bin_file, &statbuf) < 0) {
+    if (errno == ENOENT) return 1;
+    return -1;
+  }
+  time_t output_path_time = statbuf.st_mtime;
+
+  if (stat(source_file, &statbuf) < 0) {
+    fprintf(stderr, "could not stat %s: %s", source_file, strerror(errno));
+    return -1;
+  }
+
+  time_t input_path_time = statbuf.st_mtime;
+  return input_path_time > output_path_time;
+}
+
+int main(int argc, char** argv) {
+  if (needs_rebuild(argv[0], __FILE__)) {
+    RUN_CMD({CC, __FILE__, "-o", argv[0], NULL});
+    if (status != 0) {
+      // cc error
+      return 0;
+    }
+    print_cmd(argv);
+    execvp(argv[0], argv);
+  }
+
+  RUN_CMD({CC, "src/main.c", "-o", "lorem", NULL});
+  char* args[] = {"./lorem", NULL};
+  print_cmd(args);
+  execvp(args[0], args);
+}