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Date: Sun, 04 May 2003 02:53:30 +0200
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Subject: exceptions instead of errors
From: marcus.boerger@t-online.de ((Marcus =?iso-8859-1?Q?B=F6rger?=))

The following patch:
http://marcus-boerger.de/php/ext/exception.diff

allows in a short, straight forward and easy way to suppress errors and
optionally throw exceptions instead. This is supposed to be automated
by the try opcode (but that is another discussion).

The problem:
During development of SQLite i found the problem that i had to inform
the user about an error inside a constructor. This can only be done by
throwing an exception. (Repeat: this cannot be done otherwise). The
main problem herin is that we have many little utility functions that may
raise errors (like safe mode and such).

This means we had to rewrite the whole api, pass information around
or find a generic solution.

Ok here goes:

First i fixed the "ignore repeated errors" feature. Then i added some control
information to struct _php_core_globals:
         error_handling_t  error_handling;
         zend_class_entry *exception_class;

error_handling can be one of EH_NORMAL, EH_SUPPRESS and EH_THROW
- EH_NORMAL is the normal way errors are handled
- EH_SUPPRESS means the error is stored but not shown (suppressed even)
- EH_THROW throws an exception of type PG(exception_class) or the default
   exception class if PG(exception_class) is NULL.

To manually change the mode or class there is the following function:
         PHPAPI void php_set_error_handling(error_handling_t 
error_handling, zend_class_entry *exception_class TSRMLS_DC)

The mechanism itself is located in the function php_error_cb which is called
during all error calls. So every error, warning or notice is catched. BUT of
corse the mechanism doesn't work with E_ERROR, E_PARSE or such. These
are real errors and are errors even after the patch.

The reason the exception class can be set is to easily support exception 
inheritance
for the lazy programmers.

The reason to support EH_SUPPRESS is for more sophisticated problems...

When the mechanismn throws an error it automatically sets these exception
properties:
- message        the error message
- file           the filename
- line           the line number in the file

Further more i suggest we add the severity to the default exception.

Some help of the engine would be good:
- automatically set EH_THROW mode at "try"
- automatically set EH_NORMAL mode at "catch" (first outmost catch)

If noone objects i will commit this on monday evening.

Unfortunately there is a memory leak in the exception handling itself but
that is another story...and will hopefully soon be fixed by somebody else.

Anybody interested can try the patch with my patched SQLite:
http://marcus-boerger.de/html/php/ext/sqlite/
and especially look into test sqlite_oo_020.phpt

regards
marcus


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