[config] Process config.d files in alnum order

Each configuration file is kept in separate QSettings object and lookup
for values is done in load order - which is reverse from convention
where 10-something.conf can be overridden with 20-something-else.conf.

Change evaluation so that latter files can override earlier ones under
assumption that so far there have been no devices that would actually
employ more than one config.d file and thus glitches are unlikely.

Also merge data from all settings files into a single QSettings object
i.e. trade a bit more complex startup for simpler lookups during runtime.

The primary config file, if specified, still overrides any settings made
from config.d files.

Rename 90-sensord-default.conf to 10-sensord-default.conf so that it
still is 10 points up from the minimum priority.

Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

core/config.cpp

@@ -39,94 +39,68 @@ Config::Config() {
 }
 
 Config::~Config() {
-    clearConfig();
 }
 
 void Config::clearConfig() {
-    foreach(QSettings* setting, settings)
-        delete setting;
-    settings.clear();
+    m_settings.clear();
 }
 
 bool Config::loadConfig(const QString &defConfigPath, const QString &configDPath) {
-    Config *config = NULL;
+    /* Not having config files is ok, failing to load one that exists is not */
     bool ret = true;
-
-    /* Check/create new static config */
-    if (static_configuration) {
-        config = static_configuration;
-    } else {
-        config = new Config();
+    if (!static_configuration) {
+        static_configuration = new Config();
     }
-
-    if (!config->loadConfigFile(defConfigPath))
-        ret = false;
-
-    /* Scan config.d dir */
-    QStringList fileList;
-    if(!configDPath.isEmpty())
-    {
+    /* Process config.d dir in alnum order */
+    if (!configDPath.isEmpty()) {
         QDir dir(configDPath, "*.conf", QDir::Name, QDir::Files);
-        fileList = dir.entryList();
-        foreach(const QString& file, fileList)
-        {
-            if (!config->loadConfigFile(dir.absoluteFilePath(file)))
+        foreach(const QString &file, dir.entryList()) {
+            if (!static_configuration->loadConfigFile(dir.absoluteFilePath(file))) {
                 ret = false;
+            }
         }
     }
-
-    static_configuration = config;
-
+    /* Primary config file overrides config.d */
+    if (!defConfigPath.isEmpty() && QFile::exists(defConfigPath) ) {
+        if (!static_configuration->loadConfigFile(defConfigPath))
+            ret = false;
+    }
     return ret;
 }
 
 bool Config::loadConfigFile(const QString &configFileName) {
-    if(!QFile::exists(configFileName))
-    {
+    /* Success means the file was loaded and processed without hiccups */
+    bool loaded = false;
+    if (!QFile::exists(configFileName)) {
         sensordLogW() << "File does not exists \"" << configFileName <<  "\"";
-        return false;
-    }
-    QSettings* setting = new QSettings(configFileName, QSettings::IniFormat);
-    if(setting->status() == QSettings::NoError) {
-        settings.append(setting);
-        sensordLogD() << "Config file \"" << configFileName << "\" successfully loaded";
-        return true;
+    } else {
+        QSettings merge(configFileName, QSettings::IniFormat);
+        QSettings::Status status(merge.status());
+        if (status == QSettings::FormatError ) {
+            sensordLogW() << "Configuration file \"" << configFileName <<  "\" is in wrong format";
+        } else if (status != QSettings::NoError) {
+            sensordLogW() << "Unable to open \"" << configFileName <<  "\" configuration file";
+        } else {
+            foreach (const QString &key, merge.allKeys()) {
+                m_settings.setValue(key, merge.value(key));
+            }
+            loaded = true;
+        }
     }
-    else if(setting->status() == QSettings::AccessError)
-        sensordLogW() << "Unable to open \"" << configFileName <<  "\" configuration file";
-    else if(setting->status() == QSettings::FormatError)
-        sensordLogW() << "Configuration file \"" << configFileName <<  "\" is in wrong format";
-    else
-        sensordLogW() << "Configuration file \"" << configFileName <<  "\" parsing failed to unknown error: " << setting->status();
-    delete setting;
-    return false;
+    return loaded;
 }
 
 QVariant Config::value(const QString &key) const {
-    /* Iterate through configs so that keys in the first files
-     * have preference over the last.
-     */
-    foreach(QSettings* setting, settings) {
-        if(setting->contains(key))
-        {
-            QVariant var = setting->value(key, QVariant());
-            if(var.isValid())
-                sensordLogD() << "Value for key '" << key << "': " << var.toString();
-            return var;
-        }
+    QVariant var = m_settings.value(key, QVariant());
+    if(var.isValid()) {
+        sensordLogT() << "Value for key" << key << ":" << var.toString();
     }
-    return QVariant();
+    return var;
 }
 
 QStringList Config::groups() const
 {
-    QStringList groups;
-    foreach(QSettings* setting, settings) {
-        foreach(const QString& group, setting->childGroups()) {
-            if(!groups.contains(group))
-                groups << group;
-        }
-    }
+    QStringList groups = m_settings.childGroups();
     return groups;
 }
 

core/config.h

@@ -136,7 +136,7 @@ class Config
      */
     void clearConfig();
 
-    QList<QSettings*> settings; /**< parsed QSettings */
+    QSettings m_settings; /**< parsed QSettings */
 };
 
 template<typename T>

doc/PLUGIN-GUIDE

@@ -221,7 +221,8 @@ Sensorfw supports multiple configuration files. There are two locations:
   (1) /etc/sensorfw/sensord.conf
   (2) /etc/sensorfw/sensord.conf.d/
 
-Any option set in (1) will override options set in any of the files in (2). Files in (2) are given priority based on alphanumeric order. Using double-digits as the beginning of the filename for clarity is encouraged.
+Any option set in (1) will override options set in any of the files in (2). Files in (2) are processed in alpha-numerical order, and later files can override settings from earlier files. Using double-digits as the beginning of the filename for clarity is encouraged.
+
 
 Configuration files contain sections for different HW. These sections should connect plugin metanames (sampleadaptor) with the real plugin that should be used (sampleadaptor-inputdev). The configuration file also contains option 'deviceId', which specifies which section should be used. This will be removed once we have automatic detection of underlying HW in place.
 

doc/mainpage.h

@@ -694,9 +694,9 @@ Sensorfw supports multiple configuration files. There are two locations:
   (1) /etc/sensorfw/sensord.conf
   (2) /etc/sensorfw/sensord.conf.d/
 
-Any option set in (1) will override options set in any of the files in (2). Files in (2) are given
-priority based on alphanumeric order. Using double-digits as the beginning of the filename for
-clarity is encouraged.
+Any option set in (1) will override options set in any of the files in (2). Files in (2) are
+processed in alpha-numerical order, and later files can override settings from earlier files.
+Using double-digits as the beginning of the filename for clarity is encouraged.
 
 Configuration files contain sections for different HW. These sections should connect plugin
 metanames (sampleadaptor) with the real plugin that should be used (sampleadaptor-inputdev).

sensorfw.pro

@@ -104,7 +104,7 @@ equals(QT_MAJOR_VERSION, 5):  {
         DBUSCONFIGFILES.path = /etc/dbus-1/system.d
         INSTALLS += DBUSCONFIGFILES
 
-        SENSORDCONFIGFILES.files = config/90-sensord-default.conf
+        SENSORDCONFIGFILES.files = config/10-sensord-default.conf
         SENSORDCONFIGFILES.path = /etc/sensorfw/sensord.conf.d
         INSTALLS += SENSORDCONFIGFILES