This commit makes it possible to use multiple V8 execution contexts
within a single event loop. Put another way, handle and request wrap
objects now "remember" the context they belong to and switch back to
that context when the time comes to call into JS land.
This could have been done in a quick and hacky way by calling
v8::Object::GetCreationContext() on the wrap object right before
making a callback but that leaves a fairly wide margin for bugs.
Instead, we make the context explicit through a new Environment class
that encapsulates everything (or almost everything) that belongs to
the context. Variables that used to be a static or a global are now
members of the aforementioned class. An additional benefit is that
this approach should make it relatively straightforward to add full
isolate support in due course.
There is no JavaScript API yet but that will be added in the near
future.
This work was graciously sponsored by GitHub, Inc.
Buffer(<String>) used to pass the string to js where it would then be
passed back to cpp for processing. Now only the buffer object
instantiation is done in js and the string is processed in cpp.
Also added a Buffer api that also accepts the encoding.
Memory allocations are now done through smalloc. The Buffer cc class has
been removed completely, but for backwards compatibility have left the
namespace as Buffer.
The .parent attribute is only set if the Buffer is a slice of an
allocation. Which is then set to the alloc object (not a Buffer).
The .offset attribute is now a ReadOnly set to 0, for backwards
compatibility. I'd like to remove it in the future (pre v1.0).
A few alterations have been made to how arguments are either coerced or
thrown. All primitives will now be coerced to their respective values,
and (most) all out of range index requests will throw.
The indexes that are coerced were left for backwards compatibility. For
example: Buffer slice operates more like Array slice, and coerces
instead of throwing out of range indexes. This may change in the future.
The reason for wanting to throw for out of range indexes is because
giving js access to raw memory has high potential risk. To mitigate that
it's easier to make sure the developer is always quickly alerted to the
fact that their code is attempting to access beyond memory bounds.
Because SlowBuffer will be deprecated, and simply returns a new Buffer
instance, all tests on SlowBuffer have been removed.
Heapdumps will now show usage under "smalloc" instead of "Buffer".
ParseArrayIndex was added to node_internals to support proper uint
argument checking/coercion for external array data indexes.
SlabAllocator had to be updated since handle_ no longer exists.
This also templatizes the Buffer::*Slice functions, and the template
function probably cannot be safely used outside of Node. However, it
also SHOULD not be used outside of Node, so this is arguably a feature
as well as a caveat.
Move the implementation to C++ land. This is similar to commit 3f65916
but this time for the write() function and the Buffer(s, 'hex')
constructor.
Speeds up the benchmark below about 24x (2.6s vs 1:02m).
var s = 'f';
for (var i = 0; i < 26; ++i) s += s; // 64 MB
Buffer(s, 'hex');
Move the implementation to C++ land. The old JS implementation used
string concatenation, was dog slow and consumed copious amounts of
memory for large buffers. Example:
var buf = Buffer(0x1000000); // 16 MB
buf.toString('hex') // Used 3+ GB of memory.
The new implementation operates in O(n) time and space.
Fixes#4700.
Improvements:
* floating point operations are approx 4x's faster
* Now write quiet NaN's
* all read/write on floating point now done in C, so no more need for
lib/buffer_ieee754.js
* float values have more accurate min/max value checks
* add additional benchmarks for buffers read/write
* created benchmark/_bench_timer.js which is a simple library that
can be included into any benchmark and provides an intelligent tracker
for sync and async tests
* add benchmarks for DataView set methods
* add checks and tests to make sure offset is greater than 0
Use static_cast instead of reinterpret_cast when casting from void*
to another type.
This is mostly an aesthetic change but may help catch bugs when the
affected code is modified.
Work around an issue with the glibc malloc() implementation where memory blocks
are never returned to the operating system when they are allocated with brk()
and have overlapping lifecycles.
Fixes#4283.
Throw, don't abort. `new Buffer(0x3fffffff + 1)` used to bring down the process
with the following error message:
FATAL ERROR: v8::Object::SetIndexedPropertiesToExternalArrayData() length
exceeds max acceptable value
Fixes#2280.
It was decided that the performance benefits that isolates offer (faster spin-up
times for worker processes, faster inter-worker communication, possibly a lower
memory footprint) are not actual bottlenecks for most people and do not outweigh
the potential stability issues and intrusive changes to the code base that
first-class support for isolates requires.
Hence, this commit backs out all isolates-related changes.
Good bye, isolates. We hardly knew ye.
In order to do this, buffer data management was moved out of the
JS entry-point New, and into Replace.
Secondly, the constructor makes an immediate call to Replace, and
in order for ArrayData calls to work, wrapping must already be set
up. Now, the constructor takes the wrappee as a parameter.
Fedor Indutny