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1f0de66ea2
Use the flex %option reentrant and the bison option %pure-parser to make the generated scanner and parser pure, reentrant, and thread-safe. Make the generated scanner use palloc() etc. instead of malloc() etc. Previously, we only used palloc() for the buffer, but flex would still use malloc() for its internal structures. As a result, there could be some small memory leaks in case of uncaught errors. (We do catch normal syntax errors as soft errors.) Now, all the memory is under palloc() control, so there are no more such issues. Simplify flex scan buffer management: Instead of constructing the buffer from pieces and then using yy_scan_buffer(), we can just use yy_scan_string(), which does the same thing internally. The previous code was necessary because we allocated the buffer with palloc() and the rest of the state was handled by malloc(). But this is no longer the case; everything is under palloc() now. (We could even get rid of the yylex_destroy() call and just let the memory context cleanup handle everything. But for now, we preserve the existing behavior.) Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> Reviewed-by: Andreas Karlsson <andreas@proxel.se> Discussion: https://www.postgresql.org/message-id/flat/eb6faeac-2a8a-4b69-9189-c33c520e5b7b@eisentraut.org
The PostgreSQL contrib tree
---------------------------
This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree. This does not preclude their
usefulness.
User documentation for each module appears in the main SGML
documentation.
When building from the source distribution, these modules are not
built automatically, unless you build the "world" target. You can
also build and install them all by running "make all" and "make
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.
Some directories supply new user-defined functions, operators, or
types. To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command. In a fresh database,
you can simply do
CREATE EXTENSION module_name;
See the PostgreSQL documentation for more information about this
procedure.