Add interface method to get human readable option names

Pull request #2
Co-authored-by: Priydarshi Singh <dryairship@gmail.com>

Print attributes/options and their choices are usually defined in a machine-readable form which is more made for easy typing in a command line, not too long, no special characters, always in English and human-readable form for GUI (print dialogs), more verbose for easier understanding, with spaces and other special characters, translated, ...

This commit adds functionality to the library to poll the human-readable strings from the backends.

Older backends without human-readable strings can still be used. In such a case it is recommended that the dialog does either its own conversion or simply shows the machine-readable string as a last mean.

demo/print_frontend.c

@@ -251,6 +251,25 @@ gpointer parse_commands(gpointer user_data)
             PrinterObj *p = find_PrinterObj(f, printer_id, backend_name);
             pickle_printer_to_file(p, "/tmp/.printer-pickle", f);
         }
+        else if (strcmp(buf, "get-human-readable-option-name") == 0)
+        {
+            char printer_id[100];
+            char backend_name[100];
+            char option_name[100];
+            scanf("%s%s%s", printer_id, backend_name, option_name);
+            PrinterObj *p = find_PrinterObj(f, printer_id, backend_name);
+            printf("%s\n", get_human_readable_option_name(p, option_name));
+        }
+        else if (strcmp(buf, "get-human-readable-choice-name") == 0)
+        {
+            char printer_id[100];
+            char backend_name[100];
+            char option_name[100];
+            char choice_name[100];
+            scanf("%s%s%s%s", printer_id, backend_name, option_name, choice_name);
+            PrinterObj *p = find_PrinterObj(f, printer_id, backend_name);
+            printf("%s\n", get_human_readable_choice_name(p, option_name, choice_name));
+        }
     }
 }
 
@@ -278,6 +297,8 @@ void display_help()
     printf("%s\n", "get-current <option name> <printer id> <backend name>");
     printf("%s\n", "add-setting <option name> <option value> <printer id> <backend name>");
     printf("%s\n", "clear-setting <option name> <printer id> <backend name>");
+    printf("%s\n", "get-human-readable-option-name <printer id> <backend name> <option name>");
+    printf("%s\n", "get-human-readable-choice-name <printer id> <backend name> <option name> <choice name>");
 
     printf("pickle-printer <printer id> <backend name>\n");
 }

lib/frontend_helper.c

@@ -612,6 +612,34 @@ PrinterObj *resurrect_printer_from_file(const char *filename)
     return p;
 }
 
+char *get_human_readable_option_name(PrinterObj *p, char *option_name)
+{
+    char *human_readable_name;
+    GError *error = NULL;
+    print_backend_call_get_human_readable_option_name_sync(p->backend_proxy, option_name,
+                                                           &human_readable_name, NULL, &error);
+    if(error) {
+        DBG_LOG("Error getting human readable option name", ERR);
+        return option_name;
+    } else {
+        return human_readable_name;
+    }
+}
+
+char *get_human_readable_choice_name(PrinterObj *p, char *option_name, char* choice_name)
+{
+    char *human_readable_name;
+    GError *error = NULL;
+    print_backend_call_get_human_readable_choice_name_sync(p->backend_proxy, option_name, choice_name,
+                                                           &human_readable_name, NULL, &error);
+    if(error) {
+        DBG_LOG("Error getting human readable choice name", ERR);
+        return choice_name;
+    } else {
+        return human_readable_name;
+    }
+}
+
 /**
 ________________________________________________ Settings __________________________________________
 **/

lib/frontend_helper.h

@@ -324,6 +324,22 @@ void pickle_printer_to_file(PrinterObj *p, const char *filename , const Frontend
  * NULL otherwise
  */
 PrinterObj *resurrect_printer_from_file(const char *filename);
+
+/**
+ * Finds the human readable English name of the setting.
+ *
+ * @param option_name : name of the setting
+ */
+char *get_human_readable_option_name(PrinterObj *p, char *option_name);
+
+/**
+ * Finds the human readable English name of the choice for the given setting.
+ *
+ * @param option_name : name of the setting
+ * @param choice_name : value of the choice
+ */
+char *get_human_readable_choice_name(PrinterObj *p, char *option_name, char *choice_name);
+
 /************************************************************************************************/
 /**
 ______________________________________ Settings __________________________________________

lib/interface/org.openprinting.Backend.xml

@@ -25,6 +25,15 @@
             <arg name="printer_id" direction="in" type="s"/>
             <arg name="state" direction="out" type="s"/>
         </method>
+        <method name="getHumanReadableOptionName">
+            <arg name="option_name" direction="in" type="s"/>
+            <arg name="human_readable_name" direction="out" type="s"/>
+        </method>
+        <method name="getHumanReadableChoiceName">
+            <arg name="option_name" direction="in" type="s"/>
+            <arg name="choice_name" direction="in" type="s"/>
+            <arg name="human_readable_name" direction="out" type="s"/>
+        </method>
         <method name="isAcceptingJobs">
             <arg name="printer_id" direction="in" type="s"/>
             <arg name="is_accepting" direction="out" type="b"/>