Add API to set OS level file associations (#6615)

frontend/device/generic/device.lua

@@ -61,6 +61,7 @@ local Device = {
     canSuspend = yes,
     canReboot = no,
     canPowerOff = no,
+    canAssociateFileExtensions = no,
 
     -- use these only as a last resort. We should abstract the functionality
     -- and have device dependent implementations in the corresponting
@@ -311,6 +312,11 @@ end
 -- and only if allowed state is true at the time of waitForEvents() invocation.
 function Device:setAutoStandby(isAllowed) end
 
+-- Hardware specific method to set OS-level file associations to launch koreader. Expects boolean map.
+function Device:associateFileExtensions(exts)
+    logger.dbg("Device:associateFileExtensions():", util.tableSize(exts), "entries, OS handler missing")
+end
+
 -- Hardware specific method to handle usb plug in event
 function Device:usbPlugIn() end
 

frontend/document/documentregistry.lua

@@ -148,6 +148,18 @@ function DocumentRegistry:getProviders(file)
     end
 end
 
+--- Get mapping of file extensions to providers
+-- @treturn table mapping file extensions to a list of providers
+function DocumentRegistry:getExtensions()
+    local t = {}
+    for _, provider in ipairs(self.providers) do
+        local ext = provider.extension
+        t[ext] = t[ext] or {}
+        table.insert(t[ext], provider)
+    end
+    return t
+end
+
 --- Sets the preferred registered document handler.
 -- @string file
 -- @bool all

frontend/ui/elements/common_settings_menu_table.lua

@@ -48,6 +48,14 @@ if Device:canToggleMassStorage() then
     common_settings.mass_storage_actions = MassStorage:getActionsMenuTable()
 end
 
+-- Associate OS level file extensions (must be off by default, because we're not associated initially)
+if Device:canAssociateFileExtensions() then
+    common_settings.file_ext_assoc = {
+        text = _("Associate file extensions"),
+        sub_item_table = require("ui/elements/file_ext_assoc"):getSettingsMenuTable()
+    }
+end
+
 -- This affects the topmenu, we want to be able to access it even if !Device:setDateTime()
 common_settings.time = {
     text = _("Time and date"),

frontend/ui/elements/file_ext_assoc.lua

@@ -0,0 +1,71 @@
+local Device = require("device")
+local DocumentRegistry = require("document/documentregistry")
+local _ = require("gettext")
+
+local ExtAssoc = {
+    assoc = G_reader_settings:readSetting("file_ext_assoc") or {},
+}
+
+function ExtAssoc:commit()
+    G_reader_settings:saveSetting("file_ext_assoc", self.assoc):flush()
+    -- Translate the boolean map back to map of providers the OS backend can inquire further
+    local t = {}
+    for k, v in pairs(DocumentRegistry:getExtensions()) do
+        if self.assoc[k] then t[k] = v end
+    end
+    Device:associateFileExtensions(t)
+end
+
+function ExtAssoc:setAll(state)
+    for k, dummy in pairs(DocumentRegistry:getExtensions()) do
+        self:setOne(k, state)
+    end
+    self:commit()
+end
+
+function ExtAssoc:setOne(ext, state)
+    self.assoc[ext] = state and true or nil
+end
+
+function ExtAssoc:getSettingsMenuTable()
+    local ret = {
+        {
+            keep_menu_open = true,
+            text = _("Enable all"),
+            callback = function(menu)
+                self:setAll(true)
+                menu:updateItems()
+            end,
+        },
+        {
+            keep_menu_open = true,
+            text = _("Disable all"),
+            callback = function(menu)
+                self:setAll(false)
+                menu:updateItems()
+            end,
+            separator = true,
+        },
+    }
+    local exts = DocumentRegistry:getExtensions()
+    local keys = {}
+    for k, dummy in pairs(exts) do
+        table.insert(keys, k)
+    end
+    table.sort(keys)
+    for dummy, k in ipairs(keys) do
+        table.insert(ret, {
+            keep_menu_open = true,
+            text = k,
+            checked_func = function() return self.assoc[k] end,
+            callback = function()
+                self:setOne(k, not self.assoc[k])
+                self:commit()
+            end
+        })
+    end
+    return ret
+end
+
+return ExtAssoc
+

frontend/ui/elements/filemanager_menu_order.lua

@@ -47,6 +47,7 @@ local order = {
         "ignore_sleepcover",
         "ignore_open_sleepcover",
         "mass_storage_settings",
+        "file_ext_assoc",
         "screenshot",
     },
     navigation = {

frontend/ui/elements/reader_menu_order.lua

@@ -67,6 +67,7 @@ local order = {
         "ignore_sleepcover",
         "ignore_open_sleepcover",
         "mass_storage_settings",
+        "file_ext_assoc",
         "screenshot",
     },
     navigation = {