This makes zero-element hash tables, which are common, smaller, and also avoids
unnecessary malloc/free pairs.
I did some measurements during some basic browsing of a few sites. I found that
35% of all live tables were empty with a few tabs open. And cumulatively, for
the whole session, 45% of tables never had an element added to them.
I kept all the existing PL_DHashTableAdd() calls fallible, in order to be
conservative, except for the ones in nsAtomTable.cpp which already were
followed immediately by an abort on failure.
I kept all the existing PL_DHashTableAdd() calls fallible, in order to be
conservative, except for the ones in nsAtomTable.cpp which already were
followed immediately by an abort on failure.
Because they are now just equivalent to |new PLDHashTable()| +
PL_DHashTableInit() and PL_DHashTableFinish(t) + |delete t|, respectively.
They're only used in a handful of places and obscure things more than they
clarify -- I only recently worked out exactly how they different from Init()
and Finish().
Because it's no longer needed now that entry storage isn't allocated there.
(The other possible causes of failures are much less interesting and simply
crashing is a reasonable thing to do for them.)
This also makes PL_DNewHashTable() infallible.
This makes zero-element hash tables, which are common, smaller, and also avoids
unnecessary malloc/free pairs.
I did some measurements during some basic browsing of a few sites. I found that
35% of all live tables were empty with a few tabs open. And cumulatively, for
the whole session, 45% of tables never had an element added to them.
There is more to be done w.r.t. simplifying initialization, which will occur in
the next patch.
Currently the setting of PLDHashTable::ops is very haphazard.
- PLDHashTable has no constructor, so it's not auto-nulled, so lots of places
null it themselves.
- In the fallible PLDHashTable::Init() function, if the entry storage
allocation fails we'll be left with a table that has |ops| set -- indicating
it's been initialized -- but has null entry storage. I'm not certain this can
cause problems but it feels unsafe, and some (but not all) callers of Init()
null it on failure.
- PLDHashTable does not null |ops| in Finish(), so some (but not all) callers
do this themselves.
This patch makes things simpler.
- It adds a constructor that zeroes |ops|.
- It modifies Init() so that it only sets |ops| once success is ensured.
- It zeroes |ops| in Finish().
- Finally, it removes all the now-unnecessary |ops| nulling done by the users
of PLDHashTable.
ReplaceSubstring() is an O(n*m) algorithm (n being the length of the
string and m being the number of occurrences of aTarget) because we have
to move the remainder of the string, search it again and potentially
memmove most of it again as we find more matches. This patch rewrites
that function to make it O(n+m).
Note that we currently don't build TestStrings.cpp, so the test case in
this patch is not run automatically, but the test case has been verified
to pass separately by moving the test function into Gecko and calling it
during startup and stepping through it in the debugger.
--HG--
extra : rebase_source : b020e17c1973330b0dbbd6bf956c073cfdcb775e
ReplaceSubstring() is an O(n*m) algorithm (n being the length of the
string and m being the number of occurrences of aTarget) because we have
to move the remainder of the string, search it again and potentially
memmove most of it again as we find more matches. This patch rewrites
that function to make it O(n+m).
Note that we currently don't build TestStrings.cpp, so the test case in
this patch is not run automatically, but the test case has been verified
to pass separately by moving the test function into Gecko and calling it
during startup and stepping through it in the debugger.
ReplaceSubstring() is an O(n*m) algorithm (n being the length of the
string and m being the number of occurrences of aTarget) because we have
to move the remainder of the string, search it again and potentially
memmove most of it again as we find more matches. This patch rewrites
that function to make it O(n+m).
Note that we currently don't build TestStrings.cpp, so the test case in
this patch is not run automatically, but the test case has been verified
to pass separately by moving the test function into Gecko and calling it
during startup and stepping through it in the debugger.
--HG--
extra : rebase_source : 0330c130520802392b92bd094dde85f57cfe6420
xpcom/tests/unit/test_nsIProcess.js and
xpcom/tests/unit/test_nsIProcess_stress.js were failing with this commit
applied. Backout out.
CLOSED TREE
--HG--
extra : amend_source : 79cda414c263d97e77309da6ec6d58718b91d199
This also effectively changes how DMD is enabled from requiring both
replace-malloc initialization and the DMD environment variable to
requiring only the former. The DMD environment variable can still be
used to specify options, but not to disable entirely.
This however doesn't touch all the parts that do enable DMD by setting
the DMD environment variable to 1, so the code to handle this value
is kept.
There are, sadly, many combinations of linkage in use throughout the tree.
The main differentiator, though, is between program/libraries related to
Gecko or not. Kind of. Some need mozglue, some don't. Some need dependent
linkage, some standalone.
Anyways, these new templates remove the need to manually define the
right dependencies against xpcomglue, nspr, mozalloc and mozglue
in most cases.
Places that build programs and were resetting MOZ_GLUE_PROGRAM_LDFLAGS
or that build libraries and were resetting MOZ_GLUE_LDFLAGS can now
just not use those Gecko-specific templates.
OS_LIBS for libraries that are not part of the gecko tree, EXTRA_LIBS for
libraries, such as NSPR, that are in the tree, but are not handled by
moz.build just yet. Those EXTRA_LIBS may also come from a system library.
However, in cases where the expanded variables are always empty for the
in-tree case, OS_LIBS is used (as for, e.g. MOZ_ZLIB_LIBS). OS_LDFLAGS is
used exclusively for non-library linker flags.
Always pass EXTRA_LIBS before OS_LIBS on linker command lines.
Forbid EXTRA_DSO_LDOPTS, SHARED_LIBRARY_LIBS and LIBS in Makefiles.
The -*- file variable lines -*- establish per-file settings that Emacs will
pick up. This patch makes the following changes to those lines (and touches
nothing else):
- Never set the buffer's mode.
Years ago, Emacs did not have a good JavaScript mode, so it made sense
to use Java or C++ mode in .js files. However, Emacs has had js-mode for
years now; it's perfectly serviceable, and is available and enabled by
default in all major Emacs packagings.
Selecting a mode in the -*- file variable line -*- is almost always the
wrong thing to do anyway. It overrides Emacs's default choice, which is
(now) reasonable; and even worse, it overrides settings the user might
have made in their '.emacs' file for that file extension. It's only
useful when there's something specific about that particular file that
makes a particular mode appropriate.
- Correctly propagate settings that establish the correct indentation
level for this file: c-basic-offset and js2-basic-offset should be
js-indent-level. Whatever value they're given should be preserved;
different parts of our tree use different indentation styles.
- We don't use tabs in Mozilla JS code. Always set indent-tabs-mode: nil.
Remove tab-width: settings, at least in files that don't contain tab
characters.
- Remove js2-mode settings that belong in the user's .emacs file, like
js2-skip-preprocessor-directives.
Now that bug 975295 removed the obsolete wrapper class, we can rename
nsTraceRefcntImpl back to its correct pre-XPCOM-glue name,
nsTraceRefcnt.
The best part is that the one place where indentation should have needed
fixing, nsTraceRefcnt::DemangleSymbol, never had its indentation fixed
for the previous renaming.
--HG--
rename : xpcom/base/nsTraceRefcntImpl.cpp => xpcom/base/nsTraceRefcnt.cpp
rename : xpcom/base/nsTraceRefcntImpl.h => xpcom/base/nsTraceRefcnt.h
It's just as easy to directly set the preprocessor macro in the moz.build
files. Using this variable doesn't really buy us anything.
This patch also removes unused code from rdf/tests/dsds.
