RTL_CONSTASCII_(U)STRINGPARAM officially obsolete

[Lubos Lunak]

 Hello,

 I've committed all changes related to the macros and all the different 
tinderbox compilers have already compiled fine, so I consider the experiment 
successful.

 As of now, there should be no need to use either of these macros. 
OString/OUString now have overloads that handle string literals, and string 
literals convert automatically to OString/OUString, which means it should be 
fine to just use string literals without any additional stuff.

 In other words, either of these

if (foo.equalsAsciiL(RTL_CONSTASCII_STRINGPARAM("XXXXX")))
if (foo.equals(rtl::OUString(RTL_CONSTASCII_USTRINGPARAM("XXXXX"))))

can be written as

if( foo == "XXXXX" )

, this

rtl::OUString foo(RTL_CONSTASCII_USTRINGPARAM("XXXXX"));

can be written simply as

rtl::OUString foo("XXXXX");

and

functionFoo( rtl::OUString(RTL_CONSTASCII_USTRINGPARAM("XXXXX")))

can be written as

functionFoo( "XXXXX" );


 There are even more horrible multiline constructs in the code that can be 
converted to a simple one-liner, but I don't want to scare anybody :).


 I don't know if we want to encourage mass converts for this or create an Easy 
Hack, we have thousands of instances of the macros in the source, so this 
might lead to an unwanted flood.

 There are few small catches when writting new code or converting existing 
code:

- return "foo"; does not work for OUString return values 
(http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41426)

- extern const char foo[]; (i.e. extern without a size given) does not work 
with MSVC (and it's probably allowed to reject that), but this should be very 
rare and can be fixed by converting to const char* const foo or specifying 
the size

- embedded \0 in string literals is undefined, it cannot be detected at 
compile time, but there will be runtime warnings. The reason for this is this

struct foo { const char s[ 3 ]; };
const foo foos[] = { "a", "bc" };

where foos[0] is actually "a\0" (i.e. 'a', '\0', '\0' ).


 On a somewhat related note, I've also added macro SAL_DEBUG, which is like 
SAL_INFO, except that it is meant in place of the usual debug-style printf() 
calls that some people put temporarily in the code while debugging. Moreover 
I've included rtl/oustringostreaminserter.hxx directly into rtl/ustring.hxx 
(hopefully I'm right that it won't break anything in practice), so if you now 
need to know what 'foo' is, just do

SAL_DEBUG( "foo is " << foo );

 The git commit hook will reject commits with these debug outputs left in 
code.


 I have also updated 
https://wiki.documentfoundation.org/Development/String_Classes accordingly.

-- 
 Lubos Lunak
 l.lunak at suse.cz