Enable compatibility with libconfig older than v1.5

[abraha2d]

libconfig v1.4.9 is the latest version available in the RHEL / CentOS 7 repos, but Setting.lookup() was only added in v1.5.
This PR allows logiops to be compiled on these operating systems.

[PixlOne]

Thanks, I didn't know this was incompatible with older versions.

[JMoerman]

This PR broke compatibility with Ubuntu 18.04:

build_dir/src/logid/features/ThumbWheel.cpp: In static member function ‘static std::shared_ptr<logid::actions::Action> logid::features::ThumbWheel::Config::_genAction(logid::Device*, libconfig::Setting&, const string&)’:
build_dir/src/logid/features/ThumbWheel.cpp:230:36: error: no match for ‘operator[]’ (operand types are ‘libconfig::Setting’ and ‘const string {aka const std::__cxx11::basic_string<char>}’)
         auto& a_group = config_root[name];
                                    ^
In file included from build_dir/src/logid/features/../actions/gesture/../Action.h:22:0,
                 from build_dir/src/logid/features/../actions/gesture/Gesture.h:21,
                 from build_dir/src/logid/features/ThumbWheel.h:23,
                 from build_dir/src/logid/features/ThumbWheel.cpp:19:
/usr/include/libconfig.h++:223:13: note: candidate: libconfig::Setting& libconfig::Setting::operator[](const char*) const
   Setting & operator[](const char *name) const;
             ^~~~~~~~
/usr/include/libconfig.h++:223:13: note:   no known conversion for argument 1 from ‘const string {aka const std::__cxx11::basic_string<char>}’ to ‘const char*’
/usr/include/libconfig.h++:224:13: note: candidate: libconfig::Setting& libconfig::Setting::operator[](int) const
   Setting & operator[](int index) const;
             ^~~~~~~~
/usr/include/libconfig.h++:224:13: note:   no known conversion for argument 1 from ‘const string {aka const std::__cxx11::basic_string<char>}’ to ‘int’
build_dir/src/logid/features/ThumbWheel.cpp: In static member function ‘static std::shared_ptr<logid::actions::Gesture> logid::features::ThumbWheel::Config::_genGesture(logid::Device*, libconfig::Setting&, const string&)’:
build_dir/src/logid/features/ThumbWheel.cpp:247:36: error: no match for ‘operator[]’ (operand types are ‘libconfig::Setting’ and ‘const string {aka const std::__cxx11::basic_string<char>}’)
         auto& g_group = config_root[name];
                                    ^
In file included from build_dir/src/logid/features/../actions/gesture/../Action.h:22:0,
                 from build_dir/src/logid/features/../actions/gesture/Gesture.h:21,
                 from build_dir/src/logid/features/ThumbWheel.h:23,
                 from build_dir/src/logid/features/ThumbWheel.cpp:19:
/usr/include/libconfig.h++:223:13: note: candidate: libconfig::Setting& libconfig::Setting::operator[](const char*) const
   Setting & operator[](const char *name) const;
             ^~~~~~~~
/usr/include/libconfig.h++:223:13: note:   no known conversion for argument 1 from ‘const string {aka const std::__cxx11::basic_string<char>}’ to ‘const char*’
/usr/include/libconfig.h++:224:13: note: candidate: libconfig::Setting& libconfig::Setting::operator[](int) const
   Setting & operator[](int index) const;
             ^~~~~~~~

[PixlOne]

@abraha2d I'm looking at libconfig 1.4.9 on the CentOS repos and it appears that it does have support for .lookup(). Can you post the errors you were getting when compiling before this PR?

Also, because of bug #158, I'm going to have to revert this change.

[abraha2d]

This is the error I was encountering:

logiops/src/logid/Configuration.cpp: In constructor ‘logid::Configuration::Configuration(const string&)’:
logiops/src/logid/Configuration.cpp:101:29: error: ‘const class libconfig::Setting’ has no member named ‘lookup’
  101 |         auto& ignore = root.lookup("ignore");
      |                             ^~~~~~
logiops/src/logid/Configuration.cpp:119:33: error: ‘const class libconfig::Setting’ has no member named ‘lookup’
  119 |             auto& ignore = root.lookup("blacklist");
      |                                 ^~~~~~
make[2]: *** [src/logid/CMakeFiles/logid.dir/build.make:161: src/logid/CMakeFiles/logid.dir/Configuration.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:114: src/logid/CMakeFiles/logid.dir/all] Error 2
make: *** [Makefile:150: all] Error 2

[abraha2d]

libconfig v1.4.9 has Config.lookup(), but it does not have Setting.lookup(). Setting.lookup() was added in v1.5 to unify the lookup API between Config and Setting: hyperrealm/libconfig@1ff9b7f.

The issue that's occurring with my PR is a mismatch between const char* and const string when trying to find the [] operator (which for some reason my compiler isn't complaining about). I'll see if I can fix and update the PR.

[PixlOne]

Alright, thanks.

[abraha2d]

I committed a fix over on abraha2d/logiops, but I don't currently have access to an Ubuntu system to verify that it fixes the issue... It compiles fine on RHEL 7 with GCC 9.3.1.

diff --git a/src/logid/features/ThumbWheel.cpp b/src/logid/features/ThumbWheel.cpp
index 5e00926..0017080 100644
--- a/src/logid/features/ThumbWheel.cpp
+++ b/src/logid/features/ThumbWheel.cpp
@@ -227,7 +227,7 @@ std::shared_ptr<actions::Action> ThumbWheel::Config::_genAction(Device* dev,
         libconfig::Setting& config_root, const std::string& name)
 {
     try {
-        auto& a_group = config_root[name];
+        auto& a_group = config_root[name.c_str()];
         try {
             return actions::Action::makeAction(dev, a_group);
         } catch(actions::InvalidAction& e) {
@@ -244,7 +244,7 @@ std::shared_ptr<actions::Gesture> ThumbWheel::Config::_genGesture(Device* dev,
         libconfig::Setting& config_root, const std::string& name)
 {
     try {
-        auto& g_group = config_root[name];
+        auto& g_group = config_root[name.c_str()];
         try {
             auto g = actions::Gesture::makeGesture(dev, g_group);
             if(g->wheelCompatibility()) {

[PixlOne]

@ightnapovial Could you test out the fix on https://github.com/abraha2d/logiops?

[abraha2d]

fwiw I was able to test that it compiles successfully on KDE neon 5.19 (based on Ubuntu 18.04) with GCC 10.1.0.

[abraha2d]

@PixlOne Any updates on this? I've got some more PRs that are in draft (#160 and #161) pending resolution of this.