no SIGTERM handling

ddmitov · ddmitov · commit 8aa1630c6b7e · 2019-09-01T11:07:21.000+03:00
diff --git a/README.md b/README.md
@@ -82,7 +82,7 @@ in the documentation of this project are to be interpreted as described in [RFC
 
 ## Features
 
-* [PEB can be started from any folder without installation procedure.](./doc/CONSTANTS.md)
+* [PEB can be started from any folder without installation procedure.](./doc/CONSTANTS.md#files-and-folders)
 * [Perl script output is seamlessly inserted in a nice HTML user interface.](./doc/SETTINGS.md#perl-scripts-api)
 * [Event-driven interactive Perl scripts can be repeatedly fed with data.](./doc/SETTINGS.md#interactive-perl-scripts)
 * [Any version of Perl 5 can be used.](./doc/REQUIREMENTS.md#runtime-requirements)
diff --git a/doc/SETTINGS.md b/doc/SETTINGS.md
@@ -157,18 +157,10 @@ A PEB interactive Perl script should have the following features:
 * **No buffering**  
   PEB interactive scripts should have ``$|=1;`` among their first lines to disable the built-in buffering of the Perl interpreter, which prevents any output before the script has ended.
 
-* **SIGTERM handling**  
-  PEB sends the ``SIGTERM`` signal to all interactive scripts on exit for a graceful shutdown and to prevent them from becoming zombie processes. All interactive scripts must exit in 3 seconds after the ``SIGTERM`` signal is given by PEB. All unresponsive scripts are killed before PEB exits. The  ``SIGTERM`` signal may be handled by any interactive script for a graceful shutdown using the following code:
-
-  ```perl
-  $SIG{TERM} = sub {
-    # your shutdown code goes here...
-    exit();
-  };
-  ```
-
 * **Failsafe print**  
-  If a PEB instance crashes, it can still leave its interactive scripts as zombie processes consuming large amounts of memory. To prevent this scenario, all interactive scripts should test for a successful ``print`` on the STDOUT. This could be implemented using the following code:
+  Failsafe print is necessary for a graceful shutdown of Perl scripts on normal PEB exit and when PEB unexpectedly crashes. PEB closes the STDOUT and STDERR channels of all running Perl scripts when the close button is pressed - they must exit in 3 seconds or any unresponsive scripts are killed.
+
+  Failsafe print could be implemented using the following code:
 
   ```perl
   print "output string" or shutdown_procedure();
@@ -198,6 +190,7 @@ The following code shows how to start a PEB interactive Perl script right after
       interactive_script.inputData = function() {
         return document.getElementById('interactive-script-input').value;
       }
+
       interactive_script.stdoutFunction = function (stdout) {
         var container = document.getElementById('interactive-script-output');
         container.innerText = stdout;
@@ -216,7 +209,7 @@ The following code shows how to start a PEB interactive Perl script right after
 </html>
 ```
 
-The [index.htm](https://github.com/ddmitov/perl-executing-browser/blob/master/resources/app/index.html) page of the demo package demonstrates how to start one script in two instances immediately after local page is loaded.  
+The [index.htm of the demo package](https://github.com/ddmitov/perl-executing-browser/blob/master/resources/app/index.html) shows how to start one Perl script in two instances right after the PEB index page is loaded.  
 
 The [interactive.pl](https://github.com/ddmitov/perl-executing-browser/blob/master/resources/app/perl/interactive.pl) script of the demo package is an example of a Perl interactive script for PEB.
 
diff --git a/resources/app/perl-scripts/interactive.pl b/resources/app/perl-scripts/interactive.pl
@@ -79,8 +79,3 @@ sub get_input {
 sub shutdown_procedure {
   exit(0);
 }
-
-# Exit on SIGTERM signal from PEB:
-$SIG{TERM} = sub {
-  exit(0);
-};
diff --git a/src/webengine-page.h b/src/webengine-page.h
@@ -42,6 +42,7 @@ class QPage : public QWebEnginePage
 
 signals:
     void pageLoadedSignal();
+    void hideWindowSignal();
     void closeWindowSignal();
 
 public slots:
@@ -372,14 +373,10 @@ public slots:
                 QScriptHandler *handler = iterator.value();
 
                 if (handler->scriptProcess.isOpen()) {
-#ifndef Q_OS_WIN
-                    handler->scriptProcess.terminate();
-#endif
-
-#ifdef Q_OS_WIN
-                    handler->scriptProcess.kill();
-                    runningScripts.remove(iterator.key());
-#endif
+                    handler->scriptProcess
+                            .closeReadChannel(QProcess::StandardOutput);
+                    handler->scriptProcess
+                            .closeReadChannel(QProcess::StandardError);
                 }
 
                 if (!handler->scriptProcess.isOpen()) {
@@ -388,22 +385,21 @@ public slots:
             }
         }
 
-#ifndef Q_OS_WIN
         if (!runningScripts.isEmpty()) {
             int maximumTimeMilliseconds = 3000;
             QTimer::singleShot(maximumTimeMilliseconds,
                                this, SLOT(qScriptsTimeoutSlot()));
         }
-#endif
 
         if (runningScripts.isEmpty()) {
             emit closeWindowSignal();
+        } else {
+            emit hideWindowSignal();
         }
     }
 
     void qScriptsTimeoutSlot()
     {
-#ifndef Q_OS_WIN
         if (!runningScripts.isEmpty()) {
             QHash<QString, QScriptHandler*>::iterator iterator;
             for (iterator = runningScripts.begin();
@@ -418,7 +414,6 @@ public slots:
         }
 
         emit closeWindowSignal();
-#endif
     }
 
 protected:
diff --git a/src/webengine-view.cpp b/src/webengine-view.cpp
@@ -41,6 +41,9 @@ QViewWidget::QViewWidget()
     QObject::connect(this, SIGNAL(startWindowClosingSignal()),
                      mainPage, SLOT(qStartWindowClosingSlot()));
 
+    QObject::connect(mainPage, SIGNAL(hideWindowSignal()),
+                     this, SLOT(qHideWindowSlot()));
+
     QObject::connect(mainPage, SIGNAL(closeWindowSignal()),
                      this, SLOT(qCloseWindowSlot()));
 
diff --git a/src/webengine-view.h b/src/webengine-view.h
@@ -138,6 +138,14 @@ public slots:
         QViewWidget::triggerPageAction(QWebEnginePage::SelectAll);
     }
 
+    // ==============================
+    // Hide window:
+    // ==============================
+    void qHideWindowSlot()
+    {
+        this->parentWidget()->hide();
+    }
+
     // ==============================
     // Close window:
     // ==============================
diff --git a/src/webkit-page.h b/src/webkit-page.h
@@ -45,6 +45,7 @@ class QPage : public QWebPage
 
 signals:
     void pageLoadedSignal();
+    void hideWindowSignal();
     void closeWindowSignal();
 
 public slots:
@@ -385,14 +386,10 @@ public slots:
                 QScriptHandler *handler = iterator.value();
 
                 if (handler->scriptProcess.isOpen()) {
-#ifndef Q_OS_WIN
-                    handler->scriptProcess.terminate();
-#endif
-
-#ifdef Q_OS_WIN
-                    handler->scriptProcess.kill();
-                    runningScripts.remove(iterator.key());
-#endif
+                    handler->scriptProcess
+                            .closeReadChannel(QProcess::StandardOutput);
+                    handler->scriptProcess
+                            .closeReadChannel(QProcess::StandardError);
                 }
 
                 if (!handler->scriptProcess.isOpen()) {
@@ -401,22 +398,21 @@ public slots:
             }
         }
 
-#ifndef Q_OS_WIN
         if (!runningScripts.isEmpty()) {
             int maximumTimeMilliseconds = 3000;
             QTimer::singleShot(maximumTimeMilliseconds,
                                this, SLOT(qScriptsTimeoutSlot()));
         }
-#endif
 
         if (runningScripts.isEmpty()) {
             emit closeWindowSignal();
+        } else {
+            emit hideWindowSignal();
         }
     }
 
     void qScriptsTimeoutSlot()
     {
-#ifndef Q_OS_WIN
         if (!runningScripts.isEmpty()) {
             QHash<QString, QScriptHandler*>::iterator iterator;
             for (iterator = runningScripts.begin();
@@ -431,7 +427,6 @@ public slots:
         }
 
         emit closeWindowSignal();
-#endif
     }
 
 protected:
diff --git a/src/webkit-view.cpp b/src/webkit-view.cpp
@@ -49,6 +49,9 @@ QViewWidget::QViewWidget()
     QObject::connect(this, SIGNAL(startWindowClosingSignal()),
                      mainPage, SLOT(qStartWindowClosingSlot()));
 
+    QObject::connect(mainPage, SIGNAL(hideWindowSignal()),
+                     this, SLOT(qHideWindowSlot()));
+
     QObject::connect(mainPage, SIGNAL(closeWindowSignal()),
                      this, SLOT(qCloseWindowSlot()));
 
diff --git a/src/webkit-view.h b/src/webkit-view.h
@@ -143,6 +143,14 @@ public slots:
         inspector->showMaximized();
     }
 
+    // ==============================
+    // Hide window:
+    // ==============================
+    void qHideWindowSlot()
+    {
+        this->parentWidget()->hide();
+    }
+
     // ==============================
     // Close window:
     // ==============================

Original file line number	Diff line number	Diff line change
`@@ -79,8 +79,3 @@ sub get_input {`
`79`	`79`	`sub shutdown_procedure {`
`80`	`80`	`exit(0);`
`81`	`81`	`}`
`82`		`-`
`83`		`-# Exit on SIGTERM signal from PEB:`
`84`		`-$SIG{TERM} = sub {`
`85`		`- exit(0);`
`86`		`-};`
Original file line number	Diff line number	Diff line change
`@@ -42,6 +42,7 @@ class QPage : public QWebEnginePage`
`42`	`42`
`43`	`43`	`signals:`
`44`	`44`	`void pageLoadedSignal();`
	`45`	`+ void hideWindowSignal();`
`45`	`46`	`void closeWindowSignal();`
`46`	`47`
`47`	`48`	`public slots:`
`@@ -372,14 +373,10 @@ public slots:`
`372`	`373`	`QScriptHandler *handler = iterator.value();`
`373`	`374`
`374`	`375`	`if (handler->scriptProcess.isOpen()) {`
`375`		`-#ifndef Q_OS_WIN`
`376`		`- handler->scriptProcess.terminate();`
`377`		`-#endif`
`378`		`-`
`379`		`-#ifdef Q_OS_WIN`
`380`		`- handler->scriptProcess.kill();`
`381`		`- runningScripts.remove(iterator.key());`
`382`		`-#endif`
	`376`	`+ handler->scriptProcess`
	`377`	`+ .closeReadChannel(QProcess::StandardOutput);`
	`378`	`+ handler->scriptProcess`
	`379`	`+ .closeReadChannel(QProcess::StandardError);`
`383`	`380`	`}`
`384`	`381`
`385`	`382`	`if (!handler->scriptProcess.isOpen()) {`
`@@ -388,22 +385,21 @@ public slots:`
`388`	`385`	`}`
`389`	`386`	`}`
`390`	`387`
`391`		`-#ifndef Q_OS_WIN`
`392`	`388`	`if (!runningScripts.isEmpty()) {`
`393`	`389`	`int maximumTimeMilliseconds = 3000;`
`394`	`390`	`QTimer::singleShot(maximumTimeMilliseconds,`
`395`	`391`	`this, SLOT(qScriptsTimeoutSlot()));`
`396`	`392`	`}`
`397`		`-#endif`
`398`	`393`
`399`	`394`	`if (runningScripts.isEmpty()) {`
`400`	`395`	`emit closeWindowSignal();`
	`396`	`+ } else {`
	`397`	`+ emit hideWindowSignal();`
`401`	`398`	`}`
`402`	`399`	`}`
`403`	`400`
`404`	`401`	`void qScriptsTimeoutSlot()`
`405`	`402`	`{`
`406`		`-#ifndef Q_OS_WIN`
`407`	`403`	`if (!runningScripts.isEmpty()) {`
`408`	`404`	`QHash<QString, QScriptHandler*>::iterator iterator;`
`409`	`405`	`for (iterator = runningScripts.begin();`
`@@ -418,7 +414,6 @@ public slots:`
`418`	`414`	`}`
`419`	`415`
`420`	`416`	`emit closeWindowSignal();`
`421`		`-#endif`
`422`	`417`	`}`
`423`	`418`
`424`	`419`	`protected:`
Original file line number	Diff line number	Diff line change
`@@ -45,6 +45,7 @@ class QPage : public QWebPage`
`45`	`45`
`46`	`46`	`signals:`
`47`	`47`	`void pageLoadedSignal();`
	`48`	`+ void hideWindowSignal();`
`48`	`49`	`void closeWindowSignal();`
`49`	`50`
`50`	`51`	`public slots:`
`@@ -385,14 +386,10 @@ public slots:`
`385`	`386`	`QScriptHandler *handler = iterator.value();`
`386`	`387`
`387`	`388`	`if (handler->scriptProcess.isOpen()) {`
`388`		`-#ifndef Q_OS_WIN`
`389`		`- handler->scriptProcess.terminate();`
`390`		`-#endif`
`391`		`-`
`392`		`-#ifdef Q_OS_WIN`
`393`		`- handler->scriptProcess.kill();`
`394`		`- runningScripts.remove(iterator.key());`
`395`		`-#endif`
	`389`	`+ handler->scriptProcess`
	`390`	`+ .closeReadChannel(QProcess::StandardOutput);`
	`391`	`+ handler->scriptProcess`
	`392`	`+ .closeReadChannel(QProcess::StandardError);`
`396`	`393`	`}`
`397`	`394`
`398`	`395`	`if (!handler->scriptProcess.isOpen()) {`
`@@ -401,22 +398,21 @@ public slots:`
`401`	`398`	`}`
`402`	`399`	`}`
`403`	`400`
`404`		`-#ifndef Q_OS_WIN`
`405`	`401`	`if (!runningScripts.isEmpty()) {`
`406`	`402`	`int maximumTimeMilliseconds = 3000;`
`407`	`403`	`QTimer::singleShot(maximumTimeMilliseconds,`
`408`	`404`	`this, SLOT(qScriptsTimeoutSlot()));`
`409`	`405`	`}`
`410`		`-#endif`
`411`	`406`
`412`	`407`	`if (runningScripts.isEmpty()) {`
`413`	`408`	`emit closeWindowSignal();`
	`409`	`+ } else {`
	`410`	`+ emit hideWindowSignal();`
`414`	`411`	`}`
`415`	`412`	`}`
`416`	`413`
`417`	`414`	`void qScriptsTimeoutSlot()`
`418`	`415`	`{`
`419`		`-#ifndef Q_OS_WIN`
`420`	`416`	`if (!runningScripts.isEmpty()) {`
`421`	`417`	`QHash<QString, QScriptHandler*>::iterator iterator;`
`422`	`418`	`for (iterator = runningScripts.begin();`
`@@ -431,7 +427,6 @@ public slots:`
`431`	`427`	`}`
`432`	`428`
`433`	`429`	`emit closeWindowSignal();`
`434`		`-#endif`
`435`	`430`	`}`
`436`	`431`
`437`	`432`	`protected:`