inspector: move options parsing #9691

eugeneo · 2016-11-19T00:50:33Z

Checklist

make -j8 test (UNIX), or vcbuild test nosign (Windows) passes
commit message follows commit guidelines

Affected core subsystem(s)

inspector, core - some code was copied from the core to the inspector.

Description of change

As inspector functionality expands, more options will need to be added.
Currently this requires changing adding function arguments, etc. This
change packs the veriables into a single class that can be extended
without changing APIs.

eugeneo · 2016-11-19T01:20:24Z

CI: https://ci.nodejs.org/job/node-test-commit-arm/5989/

thefourtheye · 2016-11-20T15:19:33Z

src/inspector_agent.cc

@@ -1,5 +1,9 @@
 #include "inspector_agent.h"

+#if !HAVE_INSPECTOR
+#error("This file can only be used when the inspector is enabled")


Can we do this in the header file?

I meant, inspector_agent.h

Since I changed the code to process both "debugger" and inspector properties, now it lives in a dedicated header - I restored the check in the inspector_agent.h

thefourtheye · 2016-11-20T15:29:05Z

src/inspector_agent.cc

+  bool consume = false;
+  const char* port = nullptr;
+
+  if (!strncmp(option, "--debug=", sizeof("--debug=") - 1)) {


I would prefer strlen over sizeof(..) - 1. Is sizeof better than strlen here?

It's what we use everywhere else for static strings so this looks alright me.

@thefourtheye strlen is evaluated dynamically while sizeof is evaluated at compile time. I don't think this yields any perceivable gains, just the force of habit :)

thefourtheye · 2016-11-20T15:29:36Z

src/inspector_agent.cc

+    port = option + sizeof("--debug-port=") - 1;
+  // Specifying both --inspect and --debug means debugging is on, using Chromium
+  // inspector.
+  } else if (!strcmp(option, "--inspect")) {


Why not strncmp here?

It's matching against the whole string instead of just a slice.

I redid the code.

bnoordhuis

Duplicating a sizable chunk of fairly subtle code from src/node.cc is not great, IMO. Is there a way to do better?

bnoordhuis · 2016-11-21T12:25:47Z

src/inspector_agent.cc

+  bool consume = false;
+  const char* port = nullptr;
+
+  if (!strncmp(option, "--debug=", sizeof("--debug=") - 1)) {


It's what we use everywhere else for static strings so this looks alright me.

bnoordhuis · 2016-11-21T12:26:17Z

src/inspector_agent.cc

+    port = option + sizeof("--debug-port=") - 1;
+  // Specifying both --inspect and --debug means debugging is on, using Chromium
+  // inspector.
+  } else if (!strcmp(option, "--inspect")) {


It's matching against the whole string instead of just a slice.

bnoordhuis · 2016-11-21T12:30:14Z

src/inspector_agent.h

+  bool InspectorEnabled() const { return HttpEnabled(); }
+  bool HttpEnabled() const { return http_enabled_; }
+  bool WaitForConnect() const { return wait_connect_; }
+  std::string HttpHost() const { return host_; }


I realize this follows existing convention but HttpHost() is something of a misnomer since it's an address, not a free-form host name.

Aside: simple getters are usually called after the property they encapsulate minus the trailing underscore.

eugeneo · 2016-11-22T00:54:00Z

@bnoordhuis Thank you for the review. I redid the change to avoid duplication, please take another look.

bnoordhuis · 2016-11-23T12:41:20Z

src/node_debug_options.cc

+  } else if (option_name == "--debug-port" && has_argument) {
+    // Do nothing - argument will be parsed below
+  // Specifying both --inspect and --debug means debugging is on, using Chromium
+  // inspector.


Indentation is off.

bnoordhuis · 2016-11-23T12:43:03Z

src/node_debug_options.cc

+    }
+  } else {
+    const int skip =
+        (colon > 0 && port[0] == '[' && port[colon - 1] == ']') ? 1 : 0;


The ternary is superfluous here, bools decay to ints, and it makes it harder to read, IMO.

I rearranged the code a bit.

bnoordhuis · 2016-11-23T12:45:12Z

src/node_debug_options.h

+      return DebugAgentType::kDebugger;
+    }
+    return DebugAgentType::kNone;
+  }


Can you add bool IsInspector() const convenience methods? That would let you simplify conditionals in other files.

bnoordhuis · 2016-11-23T12:46:52Z

src/node_debug_options.h

+  bool WaitForConnect() const { return wait_connect_; }
+  std::string HostName() const { return host_name_; }
+  int Port() const;
+  void SetPort(int port) { port_ = port; }


It's not a big thing but I would call these hostname(), port() and set_port(). The sort-of convention in core is that CamelCase methods imply computation or side effects whereas snake_case methods are simple getters and setters.

eugeneo · 2016-11-23T19:09:26Z

@bnoordhuis Thank you for the review. Uploaded a newer version of the patch, please take another look.

eugeneo · 2016-12-01T17:56:02Z

@bnoordhuis Please take a look. CI is passing: https://ci.nodejs.org/job/node-test-pull-request/5022/

bnoordhuis

Left some suggestions. Mostly LGTM except for the !host.empty() thing, that looks like a bug or at least a very subtle foot gun.

bnoordhuis · 2016-12-01T20:49:53Z

src/node_debug_options.cc

+#include "node_debug_options.h"
+
+#include <errno.h>
+#include <string.h>


You should also include stdlib.h for the definition of exit() and strtol() and stdio.h for fprintf().

bnoordhuis · 2016-12-01T20:50:38Z

src/node_debug_options.cc

+const int default_inspector_port = 9229;
+
+inline std::string remove_brackets(const std::string& host) {
+  if (host.front() == '[' && host.back() == ']')


!host.empty() first?

Done. Thanks for pointing this out.

bnoordhuis · 2016-12-01T20:53:21Z

src/node_debug_options.cc

+  } else {
+    return std::make_pair(remove_brackets(arg.substr(0, colon)),
+                          parse_and_validate_port(arg.substr(colon + 1)));
+  }


If you omit the else, you can save a level of indent here.

bnoordhuis · 2016-12-01T20:57:58Z

src/node_debug_options.cc

+  std::string argument;
+
+  auto pos = option.find("=");
+  if (pos != std::string::npos) {


I'd swap the clauses; x == y is infinitesimally easier to parse for most people and it puts the shortest block first.

eugeneo · 2016-12-01T21:57:28Z

@bnoordhuis Thank you for the review, I uploaded the new revision.

eugeneo · 2016-12-06T22:57:43Z

Rebased on top of recent changes. This code is now ready for the review.

eugeneo · 2016-12-09T17:10:42Z

Landed as f9aadfb

As inspector functionality expands, more options will need to be added. Currently this requires changing adding function arguments, etc. This change packs the veriables into a single class that can be extended without changing APIs. PR-URL: nodejs#9691 Reviewed-By: Ben Noordhuis <[email protected]>

As inspector functionality expands, more options will need to be added. Currently this requires changing adding function arguments, etc. This change packs the veriables into a single class that can be extended without changing APIs. PR-URL: #9691 Reviewed-By: Ben Noordhuis <[email protected]>

As inspector functionality expands, more options will need to be added. Currently this requires changing adding function arguments, etc. This change packs the veriables into a single class that can be extended without changing APIs. PR-URL: nodejs#9691 Reviewed-By: Ben Noordhuis <[email protected]>

nodejs-github-bot added the c++ Issues and PRs that require attention from people who are familiar with C++. label Nov 19, 2016

thefourtheye reviewed Nov 20, 2016

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bnoordhuis requested changes Nov 21, 2016

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bnoordhuis requested changes Nov 23, 2016

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bnoordhuis requested changes Dec 1, 2016

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bnoordhuis approved these changes Dec 7, 2016

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eugeneo closed this Dec 9, 2016

Fishrock123 added the dont-land-on-v7.x label Dec 9, 2016

eugeneo deleted the args branch December 9, 2016 17:10

eugeneo merged commit f9aadfb into nodejs:master Dec 9, 2016

MylesBorins added dont-land-on-v4.x labels Jan 16, 2017

targos removed the dont-land-on-v7.x label Jan 28, 2017

italoacasas mentioned this pull request Jan 29, 2017

v7.5.0 proposal #11062

Merged

bnoordhuis mentioned this pull request Feb 28, 2017

Chrome DevTools not able to connect to Node inspect since 7.5.0 #11591

Closed

mykmelez mentioned this pull request Mar 7, 2017

src: fix building --without-v8-platform (backport v7.x) #11157

Closed

2 tasks

inspector: move options parsing #9691

inspector: move options parsing #9691

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eugeneo commented Nov 19, 2016

Checklist

Affected core subsystem(s)

Description of change

eugeneo commented Nov 19, 2016

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eugeneo commented Nov 22, 2016

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eugeneo commented Nov 23, 2016

eugeneo commented Dec 1, 2016

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eugeneo commented Dec 1, 2016

eugeneo commented Dec 6, 2016

eugeneo commented Dec 9, 2016