Check the validity of pointers before they are utilized

The cause of this issue is that there is an indirect object like '112 0 R' but no its direct object '112 0 object' in the test pdf file. Without checking the validity, it causes a null pointer when trying to get the direct object by an indirect object.


BUG=390781
R=tsepez@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/4cf36954a1676e103f899bee0138610c76500b42

[jun_fang, 2014-09-07 09:33:27]

jun_fang@foxitsoftware.com changed reviewers:
+ bo_xu@foxitsoftware.com, tsepez@chromium.org

[Bo Xu, 2014-09-08 00:47:26]

On 2014/09/07 09:33:27, jun_fang wrote:
> mailto:jun_fang@foxitsoftware.com changed reviewers:
> + mailto:bo_xu@foxitsoftware.com, mailto:tsepez@chromium.org

Should add the title line to the first line of the description.

[Bo Xu, 2014-09-08 00:54:24]

https://codereview.chromium.org/553613003/diff/1/fpdfsdk/src/fpdfppo.cpp
File fpdfsdk/src/fpdfppo.cpp (right):

https://codereview.chromium.org/553613003/diff/1/fpdfsdk/src/fpdfppo.cpp#newc...
fpdfsdk/src/fpdfppo.cpp:317: if (pRef) {
No need to check pRef since line 303 already check

[jun_fang, 2014-09-08 17:34:20]

On 2014/09/08 00:54:24, Bo Xu wrote:
> https://codereview.chromium.org/553613003/diff/1/fpdfsdk/src/fpdfppo.cpp
> File fpdfsdk/src/fpdfppo.cpp (right):
> 
>
https://codereview.chromium.org/553613003/diff/1/fpdfsdk/src/fpdfppo.cpp#newc...
> fpdfsdk/src/fpdfppo.cpp:317: if (pRef) {
> No need to check pRef since line 303 already check

It has been updated in the patch 3. Thanks.

[Tom Sepez, 2014-09-08 17:36:20]

lgtm

https://codereview.chromium.org/553613003/diff/20001/fpdfsdk/src/fpdfppo.cpp
File fpdfsdk/src/fpdfppo.cpp (right):

https://codereview.chromium.org/553613003/diff/20001/fpdfsdk/src/fpdfppo.cpp#...
fpdfsdk/src/fpdfppo.cpp:316: CPDF_Object* pClone  = NULL;
nit: maybe this reads clearer.  Your call.

CPDF_Object* pDirect = pRef->GetDirect();
if (!pDirect) {
  return 0;
}
CPDF_Object* pClone = pDirect->Clone();
if (!pClone) {
  return 0;
}

[jun_fang, 2014-09-08 17:51:19]

On 2014/09/08 17:36:20, Tom Sepez wrote:
> lgtm
> 
> https://codereview.chromium.org/553613003/diff/20001/fpdfsdk/src/fpdfppo.cpp
> File fpdfsdk/src/fpdfppo.cpp (right):
> 
>
https://codereview.chromium.org/553613003/diff/20001/fpdfsdk/src/fpdfppo.cpp#...
> fpdfsdk/src/fpdfppo.cpp:316: CPDF_Object* pClone  = NULL;
> nit: maybe this reads clearer.  Your call.
> 
> CPDF_Object* pDirect = pRef->GetDirect();
> if (!pDirect) {
>   return 0;
> }
> CPDF_Object* pClone = pDirect->Clone();
> if (!pClone) {
>   return 0;
> }

Updated in patch 4. Keep the same code format as in this file. 
In the other files, we use
if (!pClone) {
    ...
}

In this file, we use this:
if(!pClone)
{
    ...
}

[Tom Sepez, 2014-09-08 17:58:34]

Still LGTM.

https://codereview.chromium.org/553613003/diff/60001/fpdfsdk/src/fpdfppo.cpp
File fpdfsdk/src/fpdfppo.cpp (right):

https://codereview.chromium.org/553613003/diff/60001/fpdfsdk/src/fpdfppo.cpp#...
fpdfsdk/src/fpdfppo.cpp:322: CPDF_Object* pClone  = pDirect->Clone();
nit: stray space before equals.

[jun_fang, 2014-09-08 18:27:30]

Committed patchset #5 (id:80001) manually as 4cf3695 (presubmit successful).