author Henri Sivonen <>
Fri, 06 Jul 2018 10:44:43 +0300
changeset 489140 4ef0f163fdeb9afeddd87b37bfd987298c038542
parent 451980 8f74ddd39f610c992426a5e03158d89430788a31
child 524782 430cc48e530f25e83da279b8ad13ee1da2c24dbf
permissions -rw-r--r--
Bug 1402247 - Use encoding_rs for XPCOM string encoding conversions. r=Nika,erahm,froydnj. Correctness improvements: * UTF errors are handled safely per spec instead of dangerously truncating strings. * There are fewer converter implementations. Performance improvements: * The old code did exact buffer length math, which meant doing UTF math twice on each input string (once for length calculation and another time for conversion). Exact length math is more complicated when handling errors properly, which the old code didn't do. The new code does UTF math on the string content only once (when converting) but risks allocating more than once. There are heuristics in place to lower the probability of reallocation in cases where the double math avoidance isn't enough of a saving to absorb an allocation and memcpy. * Previously, in UTF-16 <-> UTF-8 conversions, an ASCII prefix was optimized but a single non-ASCII code point pessimized the rest of the string. The new code tries to get back on the fast ASCII path. * UTF-16 to Latin1 conversion guarantees less about handling of out-of-range input to eliminate an operation from the inner loop on x86/x86_64. * When assigning to a pre-existing string, the new code tries to reuse the old buffer instead of first releasing the old buffer and then allocating a new one. * When reallocating from the new code, the memcpy covers only the data that is part of the logical length of the old string instead of memcpying the whole capacity. (For old callers old excess memcpy behavior is preserved due to bogus callers. See bug 1472113.) * UTF-8 strings in XPConnect that are in the Latin1 range are passed to SpiderMonkey as Latin1. New features: * Conversion between UTF-8 and Latin1 is added in order to enable faster future interop between Rust code (or otherwise UTF-8-using code) and text node and SpiderMonkey code that uses Latin1. MozReview-Commit-ID: JaJuExfILM9

# This file is normally included by, but it is also used
# directly in python/mozbuild/mozbuild/ for gmake validation.
# We thus use INCLUDED_AUTOCONF_MK to enable/disable some parts depending
# whether a normal build is happening or whether the check is running.
installdir = $(libdir)/$(MOZ_APP_NAME)
ifeq (.,$(DEPTH))
DIST = dist
DIST = $(DEPTH)/dist
ABS_DIST = $(topobjdir)/dist

# We do magic with OBJ_SUFFIX in, the following ensures we don't
# manually use it before inclusion
OBJ_SUFFIX = $(error config/ needs to be included before using OBJ_SUFFIX)

# We only support building with a non-msys gnu make version
# strictly above 4.0.
ifdef .PYMAKE
$(error Pymake is no longer supported. Please upgrade to MozillaBuild 1.9 or newer and build with 'mach' or 'mozmake')

ifeq (a,$(firstword a$(subst /, ,$(abspath .))))
$(error MSYS make is not supported)
# 4.0- happens to be greater than 4.0, lower than the mozmake version,
# and lower than 4.0.1 or 4.1, whatever next version of gnu make will
# be released.
ifneq (4.0-,$(firstword $(sort 4.0- $(MAKE_VERSION))))
$(error Make version too old. Only versions strictly greater than 4.0 are supported.)

ifeq (a,$(firstword a$(subst /, ,$(srcdir))))
$(error MSYS-style srcdir are not supported for Windows builds.)
endif # WINNT

TIERS := $(if $(MOZ_ARTIFACT_BUILDS),artifact )pre-export export $(if $(COMPILE_ENVIRONMENT),compile )misc libs tools$(if $(filter check recurse_check,$(MAKECMDGOALS)), check)

# These defines are used to support the twin-topsrcdir model for comm-central.
  MOZILLA_DIR = $(topsrcdir)