204503 - Uninitialized variable in mozilla/netwerk/protocol/jar/src/nsJARChannel.cpp

Status: VERIFIED FIXED

(Core :: Networking, defect)

Description

[tenthumbs]

Gcc says:
 nsJARChannel.cpp:465: warning: `nsresult rv' might be used \
 uninitialized in this function

The relevant code is: 

     488     if (ext) {
     489         nsIMIMEService *mimeServ = gJarHandler->MimeService();
     490         if (mimeServ) {
     491             nsXPIDLCString mimeType;
     492             rv = mimeServ->GetTypeFromExtension(ext,
                          getter_Copies(mimeType));
     493             if (NS_SUCCEEDED(rv))
     494                 mContentType = mimeType;
     495         }
     496     }
     497     else
     498         rv = NS_ERROR_NOT_AVAILABLE;
     499 
     500     if (NS_FAILED(rv) || mContentType.IsEmpty())
     501         mContentType = NS_LITERAL_CSTRING(UNKNOWN_CONTENT_TYPE);

Not that if (ext && !mimeServ) then rv is not set.

Comment 1

[tenthumbs]

That should say: Note that if (ext && !mimeServ) the rv is not set.

Comment 2

[Darin Fisher]

pushing out since not critical that we run without a mime service...

Comment 3

[Darin Fisher]

-> suresh

Comment 4

[Alfred Kayser]

Attachment: Quick & Simple patch

Make sure that rv is initialised ok, and 
change flow in function so that it is more clear that mContentType is always
set:
if (mContentType is empty) {
    // Try to set the mContentType

    // If still empty or error set mContentType to 'UNKNOWN_CONTENT_TYPE'
}
return mContentType

This also saves a couple of code bytes

Comment 5

[Alfred Kayser]

Attachment: Even better, use only rv where needed

if (mContentType is empty) {
    // Try to set the mContentType

    if (mContent is still empty) set mContentType to 'UNKNOWN_CONTENT_TYPE'
}
return mContentType

Comment 6

[Darin Fisher]

Comment on attachment 135175 [details] [diff] [review]
Even better, use only rv where needed

r=darin

Comment 7

[Darin Fisher]

-> me (for checkin)

Comment 8

[Darin Fisher]

fixed-on-trunk

Comment 9

[benc]

http://bonsai.mozilla.org/cvsview2.cgi?diff_mode=context&whitespace_mode=show&file=nsJARChannel.cpp&branch=&root=/cvsroot&subdir=mozilla/netwerk/protocol/jar/src&command=DIFF_FRAMESET&rev1=1.105&rev2=1.106