Everything that goes in a PLDHashtable (and its derivatives, like
nsTHashtable) needs to inherit from PLDHashEntryHdr. But through a lack
of enforcement, copy constructors for these derived classes didn't
explicitly invoke the copy constructor for PLDHashEntryHdr (and the
compiler didn't invoke the copy constructor for us). Instead,
PLDHashTable explicitly copied around the bits that the copy constructor
would have.
The current setup has two problems:
1) Derived classes should be using move construction, not copy
construction, since anything that's shuffling hash table keys/entries
around will be using move construction.
2) Derived classes should take responsibility for transferring bits of
superclass state around, and not rely on something else to handle that.
The second point is not a huge problem for PLDHashTable (PLDHashTable
only has to copy PLDHashEntryHdr's bits in a single place), but future
hash table implementations that might move entries around more
aggressively would have to insert compensation code all over the
place. Additionally, if moving entries is implemented via memcpy (which
is quite common), PLDHashTable copying around bits *again* is
inefficient.
Let's fix all these problems in one go, by:
1) Explicitly declaring the set of constructors that PLDHashEntryHdr
implements (and does not implement). In particular, the copy
constructor is deleted, so any derived classes that attempt to make
themselves copyable will be detected at compile time: the compiler
will complain that the superclass type is not copyable.
This change on its own will result in many compiler errors, so...
2) Change any derived classes to implement move constructors instead of
copy constructors. Note that some of these move constructors are,
strictly speaking, unnecessary, since the relevant classes are moved
via memcpy in nsTHashtable and its derivatives.
The 'x' prefix makes it clearer that these are infallible.
A couple of nsJSID methods are now also infallible.
--HG--
extra : rebase_source : fcce44a00212d6d341afbf3827b31bd4f7355ad5
Our factory registrations already require that we store nsID pointers, which
we generally handle by using pointers to static data, or arena allocating a
copy of a dynamic ID.
Since we already have viable pointers to these IDs, there's no reason to store
an entire second copy for our hash key. We can use the pointer, instead, which
saves 16 bytes per entry.
MozReview-Commit-ID: 6MgKrXRSHv4
--HG--
extra : source : 5fb0b7746a5d56563b471e3061ccca124ea45485
extra : absorb_source : 275f5d4dc2c02e3d0391ed16e8690dac1e601758
Our factory registrations already require that we store nsID pointers, which
we generally handle by using pointers to static data, or arena allocating a
copy of a dynamic ID.
Since we already have viable pointers to these IDs, there's no reason to store
an entire second copy for our hash key. We can use the pointer, instead, which
saves 16 bytes per entry.
MozReview-Commit-ID: 6MgKrXRSHv4
--HG--
extra : rebase_source : 8d41a3fc5bc1ffe88af998bf9a0ba9ac3331a085
This removes an unnecessary level of indirection by replacing all
nsStringGlue.h instances with just nsString.h.
--HG--
extra : rebase_source : 340989240af4018f3ebfd92826ae11b0cb46d019
Bug 1134923 removed the use of those functions in gecko, and left some
for the XPCOM standalone glue. The XPCOM standalone glue was severely
stripped down in bug 1306327, with the effect of removing the
implementation for those functions.
The remains in nsXPCOM.h are:
XPCOM_API(void*) NS_Alloc(size_t aSize);
XPCOM_API(void*) NS_Realloc(void* aPtr, size_t aSize);
XPCOM_API(void) NS_Free(void* aPtr);
With no implementation left, the first arm is never actually used, and
the second arm means every remaining use of those functions in the tree
is a macro expansion to one of moz_xmalloc, moz_xrealloc or free.
--HG--
extra : rebase_source : fd1669abc5a25d8edbd5c3a8522e22a5c3f558e2
nsTHashtable::RawRemove. Add a hashtable test-suite, and
clean up some codesize issues. Also fixes bug 203030 and
hopefully SunOS build bustage. r=jkeiser sr=alecf a=asa
Boris Zbarsky
Sylvestre Ledru
Nathan Froyd
Nicholas Nethercote
Kris Maglione
Brindusan Cristian
Eric Rahm
Mike Hommey
Benjamin Smedberg
bsmedberg%covad.net
darin%meer.net
bzbarsky%mit.edu
jshin%mailaps.org
jkeiser%netscape.com