To report the capacity of the underlying buffer. The method mirrors
bytes.Buffer.Cap.
The method can be useful to know whether or not calling write or grow
methods will result in an allocation, or to know how much memory has
been allocated so far.
Fixes#26269.
Change-Id: I391db45ae825011566b594836991e28135369a78
Reviewed-on: https://go-review.googlesource.com/122835
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Despite the existing test that locks in the allocation behavior, people
really want a benchmark. So:
BenchmarkBuildString_Builder/1Write_NoGrow-4 20000000 60.4 ns/op 48 B/op 1 allocs/op
BenchmarkBuildString_Builder/3Write_NoGrow-4 10000000 230 ns/op 336 B/op 3 allocs/op
BenchmarkBuildString_Builder/3Write_Grow-4 20000000 102 ns/op 112 B/op 1 allocs/op
BenchmarkBuildString_ByteBuffer/1Write_NoGrow-4 10000000 125 ns/op 160 B/op 2 allocs/op
BenchmarkBuildString_ByteBuffer/3Write_NoGrow-4 5000000 339 ns/op 400 B/op 3 allocs/op
BenchmarkBuildString_ByteBuffer/3Write_Grow-4 5000000 316 ns/op 336 B/op 3 allocs/op
I don't think these allocate-as-fast-as-you-can benchmarks are very
interesting because they're effectively just GC benchmarks, but sure.
If one wants to see that there's 1 fewer allocation, there it is. The
ns/op and B/op numbers will change as the built string size changes.
Updates #18990
Change-Id: Ifccf535bd396217434a0e6989e195105f90132ae
Reviewed-on: https://go-review.googlesource.com/96980
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
All credit and blame goes to Ian for this suggestion, copied from the
runtime.
Fixes#23382
Updates #7921
Change-Id: I3d5a9ee4ab730c87e0f3feff3e7fceff9bcf9e18
Reviewed-on: https://go-review.googlesource.com/86976
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The Builder's ReadFrom method allows the underlying unsafe slice to
escape, and for callers to subsequently modify memory that had been
unsafely converted into an immutable string.
In the original proposal for Builder (#18990), I'd noted there should
be no Read methods:
> There would be no Reset or Bytes or Truncate or Read methods.
> Nothing that could mutate the []byte once it was unsafely converted
> to a string.
And in my prototype (https://golang.org/cl/37767), I handled ReadFrom
properly, but when https://golang.org/cl/74931 arrived, I missed that
it had a ReadFrom method and approved it.
Because we're so close to the Go 1.10 release, just remove the
ReadFrom method rather than think about possible fixes. It has
marginal utility in a Builder anyway.
Also, fix a separate bug that also allowed mutation of a slice's
backing array after it had been converted into a slice by disallowing
copies of the Builder by value.
Updates #18990Fixes#23083Fixes#23084
Change-Id: Id1f860f8a4f5f88b32213cf85108ebc609acb95f
Reviewed-on: https://go-review.googlesource.com/83255
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is like a write-only subset of bytes.Buffer with an
allocation-free String method.
Fixes#18990.
Change-Id: Icdf7240f4309a52924dc3af04a39ecd737a210f4
Reviewed-on: https://go-review.googlesource.com/74931
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
David Benjamin
Brad Fitzpatrick
Daniel Martí
Caleb Spare