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Linux: Use a hash table to map cursors (flutter/engine#19561)

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Refactors the process of looking up system mouse cursor value, so that instead of a linear search it uses a hash table.
This commit is contained in:
Tong Mu 2020-07-13 13:32:13 -07:00 committed by GitHub
parent 70de7f832c
commit a7cf911b7e
1 changed files with 42 additions and 21 deletions
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63
engine/src/flutter/shell/platform/linux/fl_mouse_cursor_plugin.cc
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@ -14,16 +14,47 @@ static constexpr char kBadArgumentsError[] = "Bad Arguments";
static constexpr char kActivateSystemCursorMethod[] = "activateSystemCursor";
static constexpr char kKindKey[] = "kind";
static constexpr char kFallbackCursor[] = "default";
struct _FlMouseCursorPlugin {
GObject parent_instance;
FlMethodChannel* channel;
FlView* view;
GHashTable* system_cursor_table;
};
G_DEFINE_TYPE(FlMouseCursorPlugin, fl_mouse_cursor_plugin, G_TYPE_OBJECT)
// Insert a new entry into a hashtable from strings to strings.
//
// Returns whether the newly added value was already in the hash table or not.
static bool define_system_cursor(GHashTable* table,
const gchar* key,
const gchar* value) {
return g_hash_table_insert(
table, reinterpret_cast<gpointer>(const_cast<gchar*>(key)),
reinterpret_cast<gpointer>(const_cast<gchar*>(value)));
}
// Populate the hash table so that it maps from Flutter's cursor kinds to GTK's
// cursor values.
//
// The table must have been created as a hashtable from strings to strings.
static void populate_system_cursor_table(GHashTable* table) {
// The following mapping must be kept in sync with Flutter framework's
// mouse_cursor.dart.
define_system_cursor(table, "none", "none");
define_system_cursor(table, "click", "pointer");
define_system_cursor(table, "text", "text");
define_system_cursor(table, "forbidden", "not-allowed");
define_system_cursor(table, "grab", "grabbing");
define_system_cursor(table, "resizeLeftRight", "ew-resize");
define_system_cursor(table, "resizeUpDown", "ns-resize");
}
// Sets the mouse cursor.
FlMethodResponse* activate_system_cursor(FlMouseCursorPlugin* self,
FlValue* args) {
@ -37,27 +68,15 @@ FlMethodResponse* activate_system_cursor(FlMouseCursorPlugin* self,
if (fl_value_get_type(kind_value) == FL_VALUE_TYPE_STRING)
kind = fl_value_get_string(kind_value);
const gchar* cursor_name = nullptr;
if (g_strcmp0(kind, "none") == 0)
cursor_name = "none";
else if (g_strcmp0(kind, "basic") == 0)
cursor_name = "default";
else if (g_strcmp0(kind, "click") == 0)
cursor_name = "pointer";
else if (g_strcmp0(kind, "text") == 0)
cursor_name = "text";
else if (g_strcmp0(kind, "forbidden") == 0)
cursor_name = "not-allowed";
else if (g_strcmp0(kind, "grab") == 0)
cursor_name = "grab";
else if (g_strcmp0(kind, "grabbing") == 0)
cursor_name = "grabbing";
else if (g_strcmp0(kind, "resizeLeftRight") == 0)
cursor_name = "ew-resize";
else if (g_strcmp0(kind, "resizeUpDown") == 0)
cursor_name = "ns-resize";
else
cursor_name = "default";
if (self->system_cursor_table == nullptr) {
self->system_cursor_table = g_hash_table_new(g_str_hash, g_str_equal);
populate_system_cursor_table(self->system_cursor_table);
}
const gchar* cursor_name = reinterpret_cast<const gchar*>(
g_hash_table_lookup(self->system_cursor_table, kind));
if (cursor_name == nullptr)
cursor_name = kFallbackCursor;
GdkWindow* window =
gtk_widget_get_window(gtk_widget_get_toplevel(GTK_WIDGET(self->view)));
@ -102,6 +121,8 @@ static void fl_mouse_cursor_plugin_dispose(GObject* object) {
self->view = nullptr;
}
g_clear_pointer(&self->system_cursor_table, g_hash_table_unref);
G_OBJECT_CLASS(fl_mouse_cursor_plugin_parent_class)->dispose(object);
}