Invalidate component freshness by source generation

src/lib/compiler.cpp

@@ -385,6 +385,11 @@ String compiler_priority_file_name(Request* context)
 	return(context->server->config["BIN_DIRECTORY"] + "/proactive-priority.txt");
 }
 
+String compiler_source_generation_file_name(Request* context)
+{
+	return(context->server->config["BIN_DIRECTORY"] + "/source-generation.txt");
+}
+
 int compiler_open_lock_file(String file_name, String purpose, bool nonblocking = false)
 {
 	(void)purpose;
@@ -906,6 +911,7 @@ void compile_shared_unit(Request* context, SharedUnit* su)
 		file_put_contents(su->compile_output_file_name, su->compiler_messages + "\n");
 		compiler_untrack_known_unit(context, su->file_name);
 		compiler_record_compile_result(su, time_precise() - comp_start, false, "missing_source", su->compiler_messages);
+		compiler_mark_source_generation(context);
 		return;
 	}
 	struct stat source_info;
@@ -922,6 +928,7 @@ void compile_shared_unit(Request* context, SharedUnit* su)
 		file_unlink(su->wasm_name);
 		compiler_record_compile_result(su, time_precise() - comp_start, false, "compile_error", su->compiler_messages);
 		printf("%s \n", compiler_format_source_read_failure(context, su, su->compiler_messages).c_str());
+		compiler_mark_source_generation(context);
 		return;
 	}
 
@@ -982,6 +989,7 @@ void compile_shared_unit(Request* context, SharedUnit* su)
 			(su->pre_path + "/" + su->pre_file_name).c_str(),
 			time_precise() - comp_start);
 	}
+	compiler_mark_source_generation(context);
 }
 
 SharedUnit* compiler_get_shared_unit_internal(Request* context, String file_name, bool force_recompile)
@@ -1074,6 +1082,25 @@ SharedUnit* get_shared_unit(Request* context, String file_name)
 	return(compiler_get_shared_unit_internal(context, file_name, false));
 }
 
+String compiler_source_generation(Request* context)
+{
+	if(!context || !context->server)
+		return("");
+	return(trim(file_get_contents(compiler_source_generation_file_name(context))));
+}
+
+void compiler_mark_source_generation(Request* context)
+{
+	if(!context || !context->server)
+		return;
+	String file_name = compiler_source_generation_file_name(context);
+	int fdlock = compiler_open_lock_file(file_name + ".lock", "source-generation");
+	if(fdlock < 0)
+		return;
+	file_put_contents(file_name, std::to_string(getpid()) + ":" + std::to_string((u64)(time_precise() * 1000000.0)) + "\n");
+	compiler_close_lock_file(fdlock);
+}
+
 String compiler_error_page_unit(Request* context, String config_key)
 {
 	if(!context || !context->server)