#14725: suspicious code in file.cpp

[wxTrac]

Ticket URL: <http://trac.wxwidgets.org/ticket/14725>

#14725: suspicious code in file.cpp
------------------------------------------+---------------------------------
Reporter: ghostvoodooman | Owner:
Type: defect | Status: new
Priority: normal | Milestone:
Component: base | Version: 2.9-svn
Keywords: file wxFile loop for ReadAll | Blockedby:
Patch: 0 | Blocking:
------------------------------------------+---------------------------------
There is suspicious code in ReadAll() function:

http://svn.wxwidgets.org/viewvc/wx/wxWidgets/trunk/src/common/file.cpp?view=markup

RealAll() function:
{{{
for ( ;; )
{
static const unsigned READSIZE = 4096;

ssize_t nread = Read(p, length > READSIZE ? READSIZE : length);
if ( nread == wxInvalidOffset )
return false;

p += nread;
}

*p = 0;

wxString strTmp(buf, conv);
str->swap(strTmp);

return true;
}}}

compiler warns about line 314 saying non-reachable code
{{{
*p = 0;
}}}

the code is not reachable, since there is infinite loop [namely "for(;;)"
construct], and inside of it there is only conditional "return" statement,
but no "break" statement. It is assumed the loop either loops infinitely
or returns "false".


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Ticket URL: <http://trac.wxwidgets.org/ticket/14725>

[wxTrac]

Ticket URL: <http://trac.wxwidgets.org/ticket/14725#comment:1>

#14725: suspicious code in file.cpp
------------------------------------------+---------------------------------

Reporter: ghostvoodooman | Owner: vadz
Type: defect | Status: accepted

Priority: normal | Milestone:
Component: base | Version: 2.9-svn
Keywords: file wxFile loop for ReadAll | Blockedby:
Patch: 0 | Blocking:
------------------------------------------+---------------------------------

Changes (by vadz):

* owner: => vadz
* status: new => accepted


Comment:

This is worse than suspicious, it's totally wrong :-( I forgot to finish
writing this function before checking it in somehow. Fixing now, thanks
for noticing this.


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Ticket URL: <http://trac.wxwidgets.org/ticket/14725#comment:1>

[wxTrac]

Ticket URL: <http://trac.wxwidgets.org/ticket/14725#comment:2>

#14725: suspicious code in file.cpp

-----------------------------+----------------------------------------------
Reporter: ghostvoodooman | Owner: vadz
Type: defect | Status: closed

Priority: normal | Milestone:
Component: base | Version: 2.9-svn

Resolution: fixed | Keywords: file wxFile loop for ReadAll
Blockedby: | Patch: 0
Blocking: |
-----------------------------+----------------------------------------------
Changes (by VZ):

* status: accepted => closed
* resolution: => fixed


Comment:

(In [72614]) Fix fatal bug in the recently added wxFile::ReadAll().

Make sure we exit the loop when reading the file in chunks in
wxFile::ReadAll() and add a unit test for it to ensure that it's really
correct.

Closes #14725.


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Ticket URL: <http://trac.wxwidgets.org/ticket/14725#comment:2>