runtime: put white gloves on when touching clojure.browser.repl/boots…

…trap

@bendlas

src/implant/dirac/implant/eval.cljs

@@ -135,8 +135,8 @@
 
 ; -- code templates ---------------------------------------------------------------------------------------------------------
 
-(defn installation-test-template []
-  (str "dirac.runtime.installed_QMARK_()"))
+(defn ^:dynamic installation-test-template []
+  (str "(dirac.runtime.installed_QMARK_() && dirac.runtime.repl.bootstrapped_QMARK_())"))
 
 (defn ^:dynamic output-template [job-id kind text]
   (str "dirac.runtime.repl.present_output(" job-id ", '" kind "', " (code-as-string text) ")"))
@@ -148,7 +148,7 @@
        "  dirac.runtime.repl.postprocess_unsuccessful_eval(e)"
        "}"))
 
-(defn console-log-template [method & args]
+(defn ^:dynamic console-log-template [method & args]
   (str "console." method "(" (string/join (interpose "," (map code-as-string args))) ")"))
 
 ; -- message templates ------------------------------------------------------------------------------------------------------

src/implant/dirac/implant/intercom.cljs

@@ -20,7 +20,7 @@
             [goog.functions :as gfns])
   (:import goog.net.WebSocket.ErrorEvent))
 
-(defonce required-repl-api-version 4)
+(defonce required-repl-api-version 5)
 
 (defonce ^:dynamic *debugger-events-subscribed* false)
 (defonce ^:dynamic *repl-connected* false)

src/runtime/dirac/runtime/bootstrap.cljs

@@ -0,0 +1,57 @@
+(ns dirac.runtime.bootstrap
+  (:require [clojure.browser.repl :as brepl]))
+
+; boostrap must be called after document finishes loading, because there may be some code coming after the bootstrap call
+; which expects goog.require to work synchronously, like @bendlas discovered
+
+(def ^:dynamic *boostrapped?* false)
+(def ^:dynamic *boostrap-timeout* 100)
+(def ^:dynamic *boostrap-listeners* (array))                                                                                  ; a native array of plain functions
+
+; -- async bootstrap wrapper ------------------------------------------------------------------------------------------------
+
+(defn notify-listeners! [listeners]
+  (doseq [listener listeners]
+    (listener)))
+
+(defn boostrap-if-needed! []
+  (when-not *boostrapped?*
+    (brepl/bootstrap)
+    (set! *boostrapped?* true))
+  (notify-listeners! *boostrap-listeners*)
+  (set! *boostrap-listeners* (array)))
+
+(defn call-after-document-finished-loading [f timeout]
+  ; Our strategy:
+  ;   If document is already loaded, we simply execute our function.
+  ;   If not, we try to schedule another check with timeout 0ms (fast path).
+  ;   If still not loaded, we repeatedly schedule future checks with timeout 100ms (until loaded).
+  ;   The magic constant *boostrap-timeout* (100ms) should be good enough for our bootstrapping use-case:
+  ;     1. we don't want to starve event queue in case of slow loading, hence non-zero timeouts
+  ;     2. but we also want to minimize the risk of potentially missing first eval request expecting bootstrapped env
+  ;        note: our own `evaluate-javascript` has a guard, but there could be some other code doing their own evals
+  ;
+  ; We use polling here because we cannot assume anything about user's code.
+  ; We do not want to hook DOMContentLoaded or onreadystatechange events which could interfere with user's own handlers.
+  ;
+  (if (= (.-readyState js/document) "loading")
+    (js/setTimeout #(call-after-document-finished-loading f *boostrap-timeout*) timeout)
+    (f)))
+
+(defn bootstrap!
+  "Reusable browser REPL bootstrapping. Patches the essential functions
+  in goog.base to support re-loading of namespaces after page load.
+
+  Note that this function might do its job asynchronously if at the time of calling the document is still loading.
+  You may provide a callback which will be called immediatelly after bootstrapping happens.
+  It has no effect if called after bootstrapping has been already done. Only the callback is called immediatelly."
+  ([] (bootstrap! nil))
+  ([callback]
+    ; patching goog methods before document finished loading can unexpectedly break following goog.require code:
+    ; `<script>goog.require("foo.bar");</script><script>foo.bar.some()</script>`
+    ; It doesn't work as expected any more, as described here: https://developers.google.com/closure/library/docs/gettingstarted#wha
+   (when (some? callback)
+     (assert (fn? callback) (str "The callback parameter to clojure.browser.repl/bootstrap expected to be a function."
+                                 "Got " (type callback) " instead."))
+     (.push *boostrap-listeners* callback))
+   (call-after-document-finished-loading boostrap-if-needed! 0)))

src/runtime/dirac/runtime/repl.cljs

@@ -1,8 +1,8 @@
 (ns dirac.runtime.repl
   (:require-macros [dirac.runtime.repl :refer [with-safe-printing]])
   (:require [goog.object]
-            [clojure.browser.repl :as brepl]
             [dirac.runtime.prefs :refer [get-prefs pref]]
+            [dirac.runtime.bootstrap :refer [bootstrap!]]
             [clojure.string :as string]
             [goog.object :as gobject]
             [goog.labs.userAgent.browser :as ua]))
@@ -20,6 +20,7 @@
   (and (ua/isChrome) (ua/isVersionOrHigher 47)))                                                                              ; Chrome 47+
 
 (def ^:dynamic *installed?* false)
+(def ^:dynamic *bootstrapped?* false)
 
 ; keep in mind that we want to avoid any state at all
 ; javascript running this code can be reloaded anytime, same with devtools front-end
@@ -111,7 +112,7 @@
 
 ; -- REPL API ---------------------------------------------------------------------------------------------------------------
 
-(def api-version 4)                                                                                                           ; version of REPL API
+(def api-version 5)                                                                                                           ; version of REPL API
 
 (defn ^:export get-api-version []
   api-version)
@@ -169,17 +170,21 @@
   (assert (string? code) "Code passed for evaluation must be a string")
   (call-dirac "eval-js" code))
 
+(defn ^:export bootstrapped? []
+  *bootstrapped?*)
+
 ; -- install/uninstall ------------------------------------------------------------------------------------------------------
 
-(defn installed? []
+(defn ^:export installed? []
   *installed?*)
 
-(defn install! []
+(defn ^:export install! []
   (when (not (installed?))
-    (brepl/bootstrap)
+    (bootstrap! #(set! *bootstrapped?* true))
     (set! *installed?* true)
     true))
 
-(defn uninstall! []
+(defn ^:export uninstall! []
   (when (installed?)
     (set! *installed?* false)))
+

test/browser/transcripts/expected/suite01-version-checks.txt

@@ -139,7 +139,7 @@ devtools #5      init-repl!
 devtools #5      setDiracPromptStatusContent('Checking for Dirac Runtime presence in your app...')
 devtools #5      setDiracPromptStatusStyle('info')
 devtools #5      setDiracPromptStatusContent('Dirac REPL API version mismatch detected.
-                 Dirac DevTools requires Dirac Runtime REPL API v4, but your version is v0.
+                 Dirac DevTools requires Dirac Runtime REPL API v5, but your version is v0.
                  Please <a href="https://github.com/binaryage/dirac/blob/master/docs/upgrading.md">upgrade Dirac Runtime</a> in your app.')
 devtools #5      setDiracPromptStatusStyle('error')
 automate #5      close-devtools!
@@ -168,7 +168,7 @@ devtools #6      init-repl!
 devtools #6      setDiracPromptStatusContent('Checking for Dirac Runtime presence in your app...')
 devtools #6      setDiracPromptStatusStyle('info')
 devtools #6      setDiracPromptStatusContent('Dirac REPL API version mismatch detected.
-                 Dirac DevTools requires Dirac Runtime REPL API v4, but your version is v1000.
+                 Dirac DevTools requires Dirac Runtime REPL API v5, but your version is v1000.
                  Please <a href="https://github.com/binaryage/dirac/blob/master/docs/upgrading.md">upgrade Dirac Runtime</a> in your app.')
 devtools #6      setDiracPromptStatusStyle('error')
 automate #6      close-devtools!