Static API Specification Mining: Exploiting Source Code Model Checking - Mining Software Specifications: Methodologies and Applications - page 138

~/X11-R6.9.0/x11perf/do_text.c
#include <X11/Xft/Xft.h> 1

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...
static XftFont *aafont;
static XftDraw *aadraw;
static XftColor aacolor;
...
int InitAAText (XParms xp, Parms p, int reps){

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int InitAAText (XParms xp, Parms p, int reps){
...
aafont = XftFontOpenName (...);
if (aafont == NULL) {
...
return 0;
} 13

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}
aadraw = XftDrawCreate (...);
if (! XftColorAllocValue (..., &aacolor)){
...
XftFontClose (xp->d, aafont);
XftDrawDestroy (aadraw);

...
return 0;
}

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}

...

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void EndAAText (XParms xp, Parms p){
...
XftDrawDestroy (aadraw);
XftFontClose (xp->d, aafont);
XftColorFree (..., &aacolor);
...

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FIGURE 5.17: Code snippet from x11perf-R6.9.0.

if there were multiple socket calls in Figure 5.16, then each socket call, along
with its corresponding related APIs, forms a different scenario.
API error-handling specifications. We identify two types of API error-
handling specifications that dictate correct error handling along all paths in
a program: error-check specifications and multiple-API specifications. Error-
check specifications dictate that correct AEC( a )'s (API-Error Checks) exist
for each API a (which can fail), before the API's return value is used or
the main procedure returns. For a given API a , absence of AEC( a ) causes
an error-check violation. Multiple-API specifications dictate that the right
clean up APIs are called along all paths. Clean up APIs are APIs called,
generally before a procedure return or program exit, to free resources such
as memory, sockets, pipes, and files or to rollback the state of a global
resource such as the system registry and databases. For example, in Fig-
ure 5.17, XftFontColose (Line 17) and XftDrawDestroy (Line 18) are the clean
up APIs in EB( XftColorAllocValue ). In Figure 5.17, one error-check specifica-
tion (the return value of XftColorAllocValue should be checked against NULL )
and two multiple-API specifications ( XftFontOpenName should be followed by