This commit improves module loading performance by at least ~25-35%
in the module-loader benchmarks.
Some optimization strategies include:
* Try-finally/try-catch isolation
* Replacing regular expressions with manual parsing
* Avoiding unnecessary string and array creation
* Avoiding constant recompilation of anonymous functions and
function definitions within functions
PR-URL: https://github.com/nodejs/node/pull/5172
Reviewed-By: James M Snell <jasnell@gmail.com>
As documented in #3042 and in [1], the existing vm implementation has
many problems. All of these are solved by @brianmcd's [contextify][2]
package. This commit uses contextify as a conceptual base and its code
core to overhaul the vm module and fix its many edge cases and caveats.
Functionally, this fixes#3042. In particular:
- A context is now indistinguishable from the object it is based on
(the "sandbox"). A context is simply a sandbox that has been marked
by the vm module, via `vm.createContext`, with special internal
information that allows scripts to be run inside of it.
- Consequently, items added to the context from anywhere are
immediately visible to all code that can access that context, both
inside and outside the virtual machine.
This commit also smooths over the API very slightly:
- Parameter defaults are now uniformly triggered via `undefined`, per
ES6 semantics and previous discussion at [3].
- Several undocumented and problematic features have been removed, e.g.
the conflation of `vm.Script` with `vm` itself, and the fact that
`Script` instances also had all static `vm` methods. The API is now
exactly as documented (although arguably the existence of the
`vm.Script` export is not yet documented, just the `Script` class
itself).
In terms of implementation, this replaces node_script.cc with
node_contextify.cc, which is derived originally from [4] (see [5]) but
has since undergone extensive modifications and iterations to expose
the most useful C++ API and use the coding conventions and utilities of
Node core.
The bindings exposed by `process.binding('contextify')`
(node_contextify.cc) replace those formerly exposed by
`process.binding('evals')` (node_script.cc). They are:
- ContextifyScript(code, [filename]), with methods:
- runInThisContext()
- runInContext(sandbox, [timeout])
- makeContext(sandbox)
From this, the vm.js file builds the entire documented vm module API.
node.js and module.js were modified to use this new native binding, or
the vm module itself where possible. This introduces an extra line or
two into the stack traces of module compilation (and thus into most
stack traces), explaining the changed tests.
The tests were also updated slightly, with all vm-related simple tests
consolidated as test/simple/test-vm-* (some of them were formerly
test/simple/test-script-*). At the same time they switched from
`common.debug` to `console.error` and were updated to use
`assert.throws` instead of rolling their own error-testing methods.
New tests were also added, of course, demonstrating the new
capabilities and fixes.
[1]: http://nodejs.org/docs/v0.10.16/api/vm.html#vm_caveats
[2]: https://github.com/brianmcd/contextify
[3]: https://github.com/joyent/node/issues/5323#issuecomment-20250726
[4]: bf123f3ef9/src/contextify.cc
[5]: https://gist.github.com/domenic/6068120
Not necessary, since we can handle the error properly on the first tick
now, even if there are event listeners, etc.
Additionally, this removes the unnecessary "_needTickCallback" from
startup, since Module.loadMain() will kick off a nextTick callback right
after it runs the main module.
Fix#4856
* Callbacks from spinner now calls its own function, separate from the
tickCallback logic
* MakeCallback will call a domain specific function if a domain is
detected
* _tickCallback assumes no domains, until nextTick receives a callback
with a domain. After that _tickCallback is overridden with the domain
specific implementation.
* _needTickCallback runs in startup() instead of nextTick (isaacs)
* Fix bug in _fatalException where exit would be called twice (isaacs)
* Process.domain has a default value of null
* Manually track nextTickQueue.length (will be useful later)
* Update tests to reflect internal api changes
So instead of:
node.js:201
throw e; // process.nextTick error, or 'error' event on first tick
^
You will now see:
path/to/foo.js:1
throw new Error('bar');
^
This is a sub-set of isaacs patch here:
https://github.com/joyent/node/issues/3235
The difference is that this patch purely adresses the exception output,
but does not try to make any behavior changes / improvements.
This patch now reports the proper throw call site for exceptions
triggered within process.nextTick. So instead of this:
node.js:201
throw e; // process.nextTick error, or 'error' event on first tick
^
You will now see:
mydir/myscript.js:15
throw new Error('My Error');
^
From my testing this patch causes no performance regressions, but does
greatly simplify processing the nextTickQueue.
V8 3.4.12.1 changed exception log format.
3.14.10:
node.js:189
throw e; // process.nextTick error, or 'error' event on first tick
^
3.4.12.1:
node.js:189
throw e; // process.nextTick error, or 'error' event on first tick
^
The caret was moved.
There are a few kinds of errors that are very confusing.
1. Errors raised in nextTick
2. Errors emitted on the "error" event
3. RangeErrors that crash the program (or anything without a stack trace)
Long traces will make make these better, of course. In the meantime, this
adds a few handy signposts (in the form of better error reporting and
comments on the otherwise inscrutable code printed to the terminal) that can
help new users find the cause, or at least, ask for help more effectively.
This patch removes require.async from nodejs.
1. It complicated the code unnecessarily.
2. Everyone uses sync require anyway.
3. It's got a lot of weird edge cases when mixed with sync require.
4. It is many months behind the commonjs spec anyhow.
Brian White
Domenic Denicola
isaacs
Trevor Norris
Bert Belder
Felix Geisendörfer
koichik
Ryan Dahl
Daniel Ennis
Jorge Chamorro Bieling
Herbert Vojčík