correct search order of dirs specified via 'sonar.cxx.includeDirectories'

[selltc]

Previously, the include directories specified via 'sonar.cxx.includeDirectories'
were not necessarily searched in the order specified. This patch corrects the
problem by storing the include paths as a list instead of a hash.

This toy project illustrates the problem, and verifies the fix:

[selltc@mac src]$ l
total 60
drwxr-xr-x  6 selltc selltc  4096 Jan  5 09:08 .
drwxrwxrwt 67 root   root   20480 Jan  5 09:08 ..
drwxr-xr-x  2 selltc selltc  4096 Jan  5 09:06 inc1
drwxr-xr-x  2 selltc selltc  4096 Jan  5 09:08 inc2
drwxr-xr-x  2 selltc selltc  4096 Jan  5 09:08 inc3
-rw-r--r--  1 selltc selltc   172 Jan  5 08:52 sonar-project.properties
-rw-r--r--  1 selltc selltc    30 Jan  5 09:08 x.c
[selltc@mac src]$ cat sonar-project.properties
sonar.projectKey=proj
sonar.projectName=proj
sonar.sources=x.c
sonar.log.level=DEBUG
sonar.cxx.cppcheck.reportPath=cppcheck.xml
sonar.cxx.includeDirectories=inc1,inc2,inc3
[selltc@mac src]$ cat x.c
#include "x.h"

int main() {}
[selltc@mac src]$ l inc1
total 8
drwxr-xr-x 2 selltc selltc 4096 Jan  5 09:06 .
drwxr-xr-x 6 selltc selltc 4096 Jan  5 09:08 ..
[selltc@mac src]$ l inc2
total 12
drwxr-xr-x 2 selltc selltc 4096 Jan  5 09:08 .
drwxr-xr-x 6 selltc selltc 4096 Jan  5 09:08 ..
-rw-r--r-- 1 selltc selltc   38 Jan  5 08:39 x.h
[selltc@mac src]$ l inc3
total 12
drwxr-xr-x 2 selltc selltc 4096 Jan  5 09:08 .
drwxr-xr-x 6 selltc selltc 4096 Jan  5 09:08 ..
-rw-r--r-- 1 selltc selltc   38 Jan  5 08:39 x.h
[selltc@mac src]$ cat inc2/x.h
int f2()
{
    char *p2;
    *p2=0;
}
[selltc@mac src]$ cat inc3/x.h
int f3()
{
    char *p3;
    *p3=0;
}
[selltc@mac src]$ cppcheck --enable=all --xml -Iinc1 -Iinc2 -Iinc3 x.c 2>cppcheck.xml
Checking x.c...
[selltc@mac src]$ cat cppcheck.xml
<?xml version="1.0" encoding="UTF-8"?>
<results>
    <error file="inc2/x.h" line="3" id="unassignedVariable" severity="style" msg="Variable &apos;p2&apos; is not assigned a value."/>
    <error file="inc2/x.h" line="4" id="uninitvar" severity="error" msg="Uninitialized variable: p2"/>
</results>

Running sonar-runner withOUT this patch yields the following output (note the expected search order of inc2 and inc3 is reversed):

...
09:10:46.583 INFO  - Sensor CxxSquidSensor
09:10:46.589 DEBUG - setIncludeDirectories() adding dir 'inc1'
09:10:46.589 DEBUG - setIncludeDirectories() adding dir 'inc2'
09:10:46.590 DEBUG - setIncludeDirectories() adding dir 'inc3'
09:10:46.644 DEBUG - storing include root: '/var/tmp/src/inc1'
09:10:46.645 DEBUG - storing include root: '/var/tmp/src/inc3'
09:10:46.645 DEBUG - storing include root: '/var/tmp/src/inc2'
09:10:46.704 DEBUG - [/var/tmp/src/x.c:1]: processing #include "x.h", resolved to file '/var/tmp/src/inc3/x.h'
09:10:46.720 DEBUG - finished preprocessing '/var/tmp/src/x.c'
...

This patch corrects the problem of the include directories being searched in
the wrong order (as the above example shows inc3 being searched before inc2).

Running sonar-runner WITH this patch yields the following output:

09:21:33.507 INFO  - Sensor CxxSquidSensor
09:21:33.510 DEBUG - setIncludeDirectories() adding dir 'inc1'
09:21:33.510 DEBUG - setIncludeDirectories() adding dir 'inc2'
09:21:33.510 DEBUG - setIncludeDirectories() adding dir 'inc3'
09:21:33.553 DEBUG - storing include root: '/var/tmp/src/inc1'
09:21:33.553 DEBUG - storing include root: '/var/tmp/src/inc2'
09:21:33.553 DEBUG - storing include root: '/var/tmp/src/inc3'
09:21:33.603 DEBUG - [/var/tmp/src/x.c:1]: processing #include "x.h", resolved to file '/var/tmp/src/inc2/x.h'

See also #745.

[guwirth]

Looks good. If impact on performance is not too high I would merge it.
👍