From edb332ed8705c72dd21274775336e5b5684384a4 Mon Sep 17 00:00:00 2001
From: Jan Steemann <jan@arangodb.com>
Date: Mon, 22 Oct 2012 10:19:49 +0200
Subject: [PATCH] issue #251: added --javascript.v8-options command line
 argument

---
 CHANGELOG                                     |  4 +++
 .../Documentation/command-line-options.dox    |  4 +++
 arangod/V8Server/ApplicationV8.cpp            | 10 ++++--
 arangod/V8Server/ApplicationV8.h              | 33 +++++++++++++++++++
 4 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index d00f0dbbe0..6301e4a529 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -32,6 +32,10 @@ v1.1.beta1 (2012-XX-XX)
   - if the length of the HTTP headers is greated than the maximum allowed size (1 MB),
     the server will fail with HTTP 431 (request header fields too large)
 
+* issue #251: allow passing arbitrary options to V8 engine using new command line option:
+  --javascript.v8-options. Using this option, the Harmony features or other settings in
+  v8 can be enabled if the end user requires them
+
 * issue #248: allow AQL optimiser to pull out completely uncorrelated subqueries to the
   top level, resulting in less repeated evaluation of the subquery
 
diff --git a/arangod/Documentation/command-line-options.dox b/arangod/Documentation/command-line-options.dox
index 321d094d27..53e70dc731 100644
--- a/arangod/Documentation/command-line-options.dox
+++ b/arangod/Documentation/command-line-options.dox
@@ -61,6 +61,7 @@
 ///      <li>@ref CommandLineArangoRemoveOnDrop "database.remove-on-compacted"</li>
 ///      <li>@ref CommandLineArangoJsGcFrequency "javascript.gc-frequency"</li>
 ///      <li>@ref CommandLineArangoJsGcInterval "javascript.gc-interval"</li>
+///      <li>@ref CommandLineArangoJsV8Options "javascript.v8-options"</li>
 ///     </ul>
 ///    </li>
 ///    <li>@ref CommandLineLogging
@@ -222,6 +223,9 @@
 /// @anchor CommandLineArangoJsGcInterval
 /// @copydetails triagens::arango::ApplicationV8::_gcInterval
 ///
+/// @anchor CommandLineArangoJsV8Options
+/// @copydetails triagens::arango::ApplicationV8::_v8Options;
+///
 /// @section CommandLineScheduler Command-Line Options for Communication
 ////////////////////////////////////////////////////////////////////////
 ///
diff --git a/arangod/V8Server/ApplicationV8.cpp b/arangod/V8Server/ApplicationV8.cpp
index 532fdbed2a..6d6c6ad58b 100644
--- a/arangod/V8Server/ApplicationV8.cpp
+++ b/arangod/V8Server/ApplicationV8.cpp
@@ -179,6 +179,7 @@ ApplicationV8::ApplicationV8 (string const& binaryPath)
     _useActions(true),
     _gcInterval(1000),
     _gcFrequency(10.0),
+    _v8Options(""),
     _startupLoader(),
     _actionLoader(),
     _vocbase(0),
@@ -485,12 +486,10 @@ void ApplicationV8::setupOptions (map<string, basics::ProgramOptionsDescription>
   options["JAVASCRIPT Options:help-admin"]
     ("javascript.gc-interval", &_gcInterval, "JavaScript request-based garbage collection interval (each x requests)")
     ("javascript.gc-frequency", &_gcFrequency, "JavaScript time-based garbage collection frequency (each x seconds)")
-  ;
-
-  options["JAVASCRIPT Options:help-admin"]
     ("javascript.action-directory", &_actionPath, "path to the JavaScript action directory")
     ("javascript.modules-path", &_startupModules, "one or more directories separated by (semi-) colons")
     ("javascript.startup-directory", &_startupPath, "path to the directory containing alternate JavaScript startup scripts")
+    ("javascript.v8-options", &_v8Options, "options to pass to v8")
   ;
 }
 
@@ -546,6 +545,11 @@ bool ApplicationV8::prepare () {
     }
   }
 
+  if (_v8Options.size() > 0) {
+    LOGGER_INFO << "using V8 options '" << _v8Options << "'";
+    v8::V8::SetFlagsFromString(_v8Options.c_str(), _v8Options.size());
+  }
+
   // setup instances
   _contexts = new V8Context*[_nrInstances];
 
diff --git a/arangod/V8Server/ApplicationV8.h b/arangod/V8Server/ApplicationV8.h
index b184688ff8..5d984f13b8 100644
--- a/arangod/V8Server/ApplicationV8.h
+++ b/arangod/V8Server/ApplicationV8.h
@@ -385,6 +385,39 @@ namespace triagens {
 
         double _gcFrequency;
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief optional arguments to pass to v8
+///
+/// @CMDOPT{\-\-javascript.v8-options @CA{options}}
+///
+/// Optional arguments to pass to the V8 Javascript engine. The V8 engine will
+/// run with default settings unless explicit options are specified using this
+/// option. The options passed will be forwarded to the V8 engine which will
+/// parse them on its own. Passing invalid options may result in an error being
+/// printed on stderr and the option being ignored.
+///
+/// Options need to be passed in one string, with V8 option names being prefixed
+/// with double dashes. Multiple options need to be separated by whitespace.
+/// To get a list of all available V8 options, you can use
+/// the value @LIT{"--help"} as follows:
+/// @code
+/// --javascript.v8-options "--help"
+/// @endcode
+///
+/// Another example of specific V8 options being set at startup:
+/// @code
+/// --javascript.v8-options "--harmony --log"
+/// @endcode
+///
+/// Names and features or usable options depend on the version of V8 being used,
+/// and might change in the future if a different version of V8 is being used
+/// in ArangoDB. Not all options offered by V8 might be sensible to use in the
+/// context of ArangoDB. Use the specific options only if you are sure that
+/// they are not harmful for the regular database operation.
+////////////////////////////////////////////////////////////////////////////////
+
+        string _v8Options;
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief V8 startup loader
 ////////////////////////////////////////////////////////////////////////////////