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333 lines
9.0 KiB
333 lines
9.0 KiB
/*
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* Node.js-like module loading framework for Duktape
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*
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* https://nodejs.org/api/modules.html
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*/
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#include "duktape.h"
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#include "duk_module_node.h"
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#if DUK_VERSION >= 19999
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static duk_int_t duk__eval_module_source(duk_context *ctx, void *udata);
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#else
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static duk_int_t duk__eval_module_source(duk_context *ctx);
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#endif
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static void duk__push_module_object(duk_context *ctx, const char *id, duk_bool_t main);
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static duk_bool_t duk__get_cached_module(duk_context *ctx, const char *id) {
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duk_push_global_stash(ctx);
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(void) duk_get_prop_string(ctx, -1, "\xff" "requireCache");
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if (duk_get_prop_string(ctx, -1, id)) {
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duk_remove(ctx, -2);
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duk_remove(ctx, -2);
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return 1;
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} else {
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duk_pop_3(ctx);
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return 0;
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}
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}
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/* Place a `module` object on the top of the value stack into the require cache
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* based on its `.id` property. As a convenience to the caller, leave the
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* object on top of the value stack afterwards.
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*/
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static void duk__put_cached_module(duk_context *ctx) {
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/* [ ... module ] */
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duk_push_global_stash(ctx);
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(void) duk_get_prop_string(ctx, -1, "\xff" "requireCache");
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duk_dup(ctx, -3);
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/* [ ... module stash req_cache module ] */
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(void) duk_get_prop_string(ctx, -1, "id");
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duk_dup(ctx, -2);
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duk_put_prop(ctx, -4);
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duk_pop_3(ctx); /* [ ... module ] */
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}
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static void duk__del_cached_module(duk_context *ctx, const char *id) {
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duk_push_global_stash(ctx);
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(void) duk_get_prop_string(ctx, -1, "\xff" "requireCache");
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duk_del_prop_string(ctx, -1, id);
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duk_pop_2(ctx);
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}
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static duk_ret_t duk__handle_require(duk_context *ctx) {
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/*
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* Value stack handling here is a bit sloppy but should be correct.
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* Call handling will clean up any extra garbage for us.
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*/
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const char *id;
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const char *parent_id;
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duk_idx_t module_idx;
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duk_idx_t stash_idx;
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duk_int_t ret;
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duk_push_global_stash(ctx);
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stash_idx = duk_normalize_index(ctx, -1);
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duk_push_current_function(ctx);
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(void) duk_get_prop_string(ctx, -1, "\xff" "moduleId");
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parent_id = duk_require_string(ctx, -1);
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(void) parent_id; /* not used directly; suppress warning */
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/* [ id stash require parent_id ] */
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id = duk_require_string(ctx, 0);
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(void) duk_get_prop_string(ctx, stash_idx, "\xff" "modResolve");
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duk_dup(ctx, 0); /* module ID */
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duk_dup(ctx, -3); /* parent ID */
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duk_call(ctx, 2);
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/* [ ... stash ... resolved_id ] */
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id = duk_require_string(ctx, -1);
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if (duk__get_cached_module(ctx, id)) {
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goto have_module; /* use the cached module */
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}
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duk__push_module_object(ctx, id, 0 /*main*/);
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duk__put_cached_module(ctx); /* module remains on stack */
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/*
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* From here on out, we have to be careful not to throw. If it can't be
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* avoided, the error must be caught and the module removed from the
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* require cache before rethrowing. This allows the application to
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* reattempt loading the module.
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*/
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module_idx = duk_normalize_index(ctx, -1);
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/* [ ... stash ... resolved_id module ] */
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(void) duk_get_prop_string(ctx, stash_idx, "\xff" "modLoad");
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duk_dup(ctx, -3); /* resolved ID */
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(void) duk_get_prop_string(ctx, module_idx, "exports");
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duk_dup(ctx, module_idx);
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ret = duk_pcall(ctx, 3);
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if (ret != DUK_EXEC_SUCCESS) {
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duk__del_cached_module(ctx, id);
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(void) duk_throw(ctx); /* rethrow */
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}
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if (duk_is_string(ctx, -1)) {
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duk_int_t ret;
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/* [ ... module source ] */
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#if DUK_VERSION >= 19999
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ret = duk_safe_call(ctx, duk__eval_module_source, NULL, 2, 1);
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#else
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ret = duk_safe_call(ctx, duk__eval_module_source, 2, 1);
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#endif
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if (ret != DUK_EXEC_SUCCESS) {
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duk__del_cached_module(ctx, id);
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(void) duk_throw(ctx); /* rethrow */
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}
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} else if (duk_is_undefined(ctx, -1)) {
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duk_pop(ctx);
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} else {
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duk__del_cached_module(ctx, id);
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(void) duk_type_error(ctx, "invalid module load callback return value");
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}
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/* fall through */
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have_module:
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/* [ ... module ] */
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(void) duk_get_prop_string(ctx, -1, "exports");
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return 1;
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}
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static void duk__push_require_function(duk_context *ctx, const char *id) {
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duk_push_c_function(ctx, duk__handle_require, 1);
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duk_push_string(ctx, "name");
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duk_push_string(ctx, "require");
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duk_def_prop(ctx, -3, DUK_DEFPROP_HAVE_VALUE);
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duk_push_string(ctx, id);
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duk_put_prop_string(ctx, -2, "\xff" "moduleId");
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/* require.cache */
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duk_push_global_stash(ctx);
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(void) duk_get_prop_string(ctx, -1, "\xff" "requireCache");
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duk_put_prop_string(ctx, -3, "cache");
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duk_pop(ctx);
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/* require.main */
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duk_push_global_stash(ctx);
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(void) duk_get_prop_string(ctx, -1, "\xff" "mainModule");
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duk_put_prop_string(ctx, -3, "main");
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duk_pop(ctx);
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}
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static void duk__push_module_object(duk_context *ctx, const char *id, duk_bool_t main) {
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duk_push_object(ctx);
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/* Set this as the main module, if requested */
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if (main) {
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duk_push_global_stash(ctx);
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duk_dup(ctx, -2);
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duk_put_prop_string(ctx, -2, "\xff" "mainModule");
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duk_pop(ctx);
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}
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/* Node.js uses the canonicalized filename of a module for both module.id
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* and module.filename. We have no concept of a file system here, so just
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* use the module ID for both values.
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*/
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duk_push_string(ctx, id);
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duk_dup(ctx, -1);
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duk_put_prop_string(ctx, -3, "filename");
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duk_put_prop_string(ctx, -2, "id");
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/* module.exports = {} */
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duk_push_object(ctx);
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duk_put_prop_string(ctx, -2, "exports");
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/* module.loaded = false */
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duk_push_false(ctx);
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duk_put_prop_string(ctx, -2, "loaded");
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/* module.require */
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duk__push_require_function(ctx, id);
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duk_put_prop_string(ctx, -2, "require");
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}
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#if DUK_VERSION >= 19999
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static duk_int_t duk__eval_module_source(duk_context *ctx, void *udata) {
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#else
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static duk_int_t duk__eval_module_source(duk_context *ctx) {
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#endif
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const char *src;
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/*
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* Stack: [ ... module source ]
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*/
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#if DUK_VERSION >= 19999
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(void) udata;
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#endif
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/* Wrap the module code in a function expression. This is the simplest
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* way to implement CommonJS closure semantics and matches the behavior of
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* e.g. Node.js.
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*/
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duk_push_string(ctx, "(function(exports,require,module,__filename,__dirname){");
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src = duk_require_string(ctx, -2);
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duk_push_string(ctx, (src[0] == '#' && src[1] == '!') ? "//" : ""); /* Shebang support. */
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duk_dup(ctx, -3); /* source */
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duk_push_string(ctx, "\n})"); /* Newline allows module last line to contain a // comment. */
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duk_concat(ctx, 4);
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/* [ ... module source func_src ] */
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(void) duk_get_prop_string(ctx, -3, "filename");
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duk_compile(ctx, DUK_COMPILE_EVAL);
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duk_call(ctx, 0);
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/* [ ... module source func ] */
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/* Set name for the wrapper function. */
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duk_push_string(ctx, "name");
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duk_push_string(ctx, "main");
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duk_def_prop(ctx, -3, DUK_DEFPROP_HAVE_VALUE | DUK_DEFPROP_FORCE);
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/* call the function wrapper */
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(void) duk_get_prop_string(ctx, -3, "exports"); /* exports */
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(void) duk_get_prop_string(ctx, -4, "require"); /* require */
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duk_dup(ctx, -5); /* module */
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(void) duk_get_prop_string(ctx, -6, "filename"); /* __filename */
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duk_push_undefined(ctx); /* __dirname */
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duk_call(ctx, 5);
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/* [ ... module source result(ignore) ] */
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/* module.loaded = true */
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duk_push_true(ctx);
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duk_put_prop_string(ctx, -4, "loaded");
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/* [ ... module source retval ] */
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duk_pop_2(ctx);
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/* [ ... module ] */
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return 1;
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}
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/* Load a module as the 'main' module. */
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duk_ret_t duk_module_node_peval_main(duk_context *ctx, const char *path) {
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/*
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* Stack: [ ... source ]
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*/
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duk__push_module_object(ctx, path, 1 /*main*/);
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/* [ ... source module ] */
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duk_dup(ctx, 0);
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/* [ ... source module source ] */
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#if DUK_VERSION >= 19999
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return duk_safe_call(ctx, duk__eval_module_source, NULL, 2, 1);
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#else
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return duk_safe_call(ctx, duk__eval_module_source, 2, 1);
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#endif
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}
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void duk_module_node_init(duk_context *ctx) {
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/*
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* Stack: [ ... options ] => [ ... ]
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*/
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duk_idx_t options_idx;
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duk_require_object_coercible(ctx, -1); /* error before setting up requireCache */
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options_idx = duk_require_normalize_index(ctx, -1);
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/* Initialize the require cache to a fresh object. */
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duk_push_global_stash(ctx);
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#if DUK_VERSION >= 19999
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duk_push_bare_object(ctx);
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#else
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duk_push_object(ctx);
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duk_push_undefined(ctx);
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duk_set_prototype(ctx, -2);
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#endif
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duk_put_prop_string(ctx, -2, "\xff" "requireCache");
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duk_pop(ctx);
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/* Stash callbacks for later use. User code can overwrite them later
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* on directly by accessing the global stash.
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*/
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duk_push_global_stash(ctx);
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duk_get_prop_string(ctx, options_idx, "resolve");
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duk_require_function(ctx, -1);
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duk_put_prop_string(ctx, -2, "\xff" "modResolve");
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duk_get_prop_string(ctx, options_idx, "load");
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duk_require_function(ctx, -1);
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duk_put_prop_string(ctx, -2, "\xff" "modLoad");
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duk_pop(ctx);
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/* Stash main module. */
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duk_push_global_stash(ctx);
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duk_push_undefined(ctx);
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duk_put_prop_string(ctx, -2, "\xff" "mainModule");
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duk_pop(ctx);
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/* register `require` as a global function. */
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duk_push_global_object(ctx);
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duk_push_string(ctx, "require");
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duk__push_require_function(ctx, "");
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duk_def_prop(ctx, -3, DUK_DEFPROP_HAVE_VALUE |
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DUK_DEFPROP_SET_WRITABLE |
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DUK_DEFPROP_SET_CONFIGURABLE);
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duk_pop(ctx);
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duk_pop(ctx); /* pop argument */
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}
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