qobject: introduce qobject_get_try_str()

A quick way to fetch string from qobject when it's a QString.

Backports commit b26ae1cb8eb0756524e322169138830b9b542311 from qemu

qemu/aarch64.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_aarch64
 #define qlit_equal_qobject qlit_equal_qobject_aarch64
 #define qobject_from_qlit qobject_from_qlit_aarch64
+#define qobject_get_try_str qobject_get_try_str_aarch64
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_aarch64
 #define qobject_input_end_list qobject_input_end_list_aarch64
 #define qobject_input_end_struct qobject_input_end_struct_aarch64

qemu/aarch64eb.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_aarch64eb
 #define qlit_equal_qobject qlit_equal_qobject_aarch64eb
 #define qobject_from_qlit qobject_from_qlit_aarch64eb
+#define qobject_get_try_str qobject_get_try_str_aarch64eb
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_aarch64eb
 #define qobject_input_end_list qobject_input_end_list_aarch64eb
 #define qobject_input_end_struct qobject_input_end_struct_aarch64eb

qemu/arm.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_arm
 #define qlit_equal_qobject qlit_equal_qobject_arm
 #define qobject_from_qlit qobject_from_qlit_arm
+#define qobject_get_try_str qobject_get_try_str_arm
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_arm
 #define qobject_input_end_list qobject_input_end_list_arm
 #define qobject_input_end_struct qobject_input_end_struct_arm

qemu/armeb.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_armeb
 #define qlit_equal_qobject qlit_equal_qobject_armeb
 #define qobject_from_qlit qobject_from_qlit_armeb
+#define qobject_get_try_str qobject_get_try_str_armeb
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_armeb
 #define qobject_input_end_list qobject_input_end_list_armeb
 #define qobject_input_end_struct qobject_input_end_struct_armeb

qemu/header_gen.py

@@ -2210,6 +2210,7 @@ symbols = (
     'qlist_type',
     'qlit_equal_qobject',
     'qobject_from_qlit',
+    'qobject_get_try_str',
     'qobject_input_end_implicit_struct',
     'qobject_input_end_list',
     'qobject_input_end_struct',

qemu/include/qapi/qmp/qstring.h

@@ -29,6 +29,7 @@ QString *qstring_from_substr(const char *str, int start, int end);
 size_t qstring_get_length(const QString *qstring);
 const char *qstring_get_str(const QString *qstring);
 const char *qstring_get_try_str(const QString *qstring);
+const char *qobject_get_try_str(const QObject *qstring);
 void qstring_append_int(QString *qstring, int64_t value);
 void qstring_append(QString *qstring, const char *str);
 void qstring_append_chr(QString *qstring, int c);

qemu/m68k.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_m68k
 #define qlit_equal_qobject qlit_equal_qobject_m68k
 #define qobject_from_qlit qobject_from_qlit_m68k
+#define qobject_get_try_str qobject_get_try_str_m68k
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_m68k
 #define qobject_input_end_list qobject_input_end_list_m68k
 #define qobject_input_end_struct qobject_input_end_struct_m68k

qemu/mips.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_mips
 #define qlit_equal_qobject qlit_equal_qobject_mips
 #define qobject_from_qlit qobject_from_qlit_mips
+#define qobject_get_try_str qobject_get_try_str_mips
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_mips
 #define qobject_input_end_list qobject_input_end_list_mips
 #define qobject_input_end_struct qobject_input_end_struct_mips

qemu/mips64.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_mips64
 #define qlit_equal_qobject qlit_equal_qobject_mips64
 #define qobject_from_qlit qobject_from_qlit_mips64
+#define qobject_get_try_str qobject_get_try_str_mips64
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_mips64
 #define qobject_input_end_list qobject_input_end_list_mips64
 #define qobject_input_end_struct qobject_input_end_struct_mips64

qemu/mips64el.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_mips64el
 #define qlit_equal_qobject qlit_equal_qobject_mips64el
 #define qobject_from_qlit qobject_from_qlit_mips64el
+#define qobject_get_try_str qobject_get_try_str_mips64el
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_mips64el
 #define qobject_input_end_list qobject_input_end_list_mips64el
 #define qobject_input_end_struct qobject_input_end_struct_mips64el

qemu/mipsel.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_mipsel
 #define qlit_equal_qobject qlit_equal_qobject_mipsel
 #define qobject_from_qlit qobject_from_qlit_mipsel
+#define qobject_get_try_str qobject_get_try_str_mipsel
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_mipsel
 #define qobject_input_end_list qobject_input_end_list_mipsel
 #define qobject_input_end_struct qobject_input_end_struct_mipsel

qemu/powerpc.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_powerpc
 #define qlit_equal_qobject qlit_equal_qobject_powerpc
 #define qobject_from_qlit qobject_from_qlit_powerpc
+#define qobject_get_try_str qobject_get_try_str_powerpc
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_powerpc
 #define qobject_input_end_list qobject_input_end_list_powerpc
 #define qobject_input_end_struct qobject_input_end_struct_powerpc

qemu/qobject/qstring.c

@@ -134,6 +134,17 @@ bool qstring_is_equal(const QObject *x, const QObject *y)
                    qobject_to(QString, y)->string);
 }
 
+/**
+ * qobject_get_try_str(): Return a pointer to the corresponding string
+ *
+ * NOTE: the string will only be returned if the object is valid, and
+ * its type is QString, otherwise NULL is returned.
+ */
+const char *qobject_get_try_str(const QObject *qstring)
+{
+    return qstring_get_try_str(qobject_to(QString, qstring));
+}
+
 /**
  * qstring_destroy_obj(): Free all memory allocated by a QString
  * object

qemu/sparc.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_sparc
 #define qlit_equal_qobject qlit_equal_qobject_sparc
 #define qobject_from_qlit qobject_from_qlit_sparc
+#define qobject_get_try_str qobject_get_try_str_sparc
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_sparc
 #define qobject_input_end_list qobject_input_end_list_sparc
 #define qobject_input_end_struct qobject_input_end_struct_sparc

qemu/sparc64.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_sparc64
 #define qlit_equal_qobject qlit_equal_qobject_sparc64
 #define qobject_from_qlit qobject_from_qlit_sparc64
+#define qobject_get_try_str qobject_get_try_str_sparc64
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_sparc64
 #define qobject_input_end_list qobject_input_end_list_sparc64
 #define qobject_input_end_struct qobject_input_end_struct_sparc64

qemu/x86_64.h

@@ -2204,6 +2204,7 @@
 #define qlist_type qlist_type_x86_64
 #define qlit_equal_qobject qlit_equal_qobject_x86_64
 #define qobject_from_qlit qobject_from_qlit_x86_64
+#define qobject_get_try_str qobject_get_try_str_x86_64
 #define qobject_input_end_implicit_struct qobject_input_end_implicit_struct_x86_64
 #define qobject_input_end_list qobject_input_end_list_x86_64
 #define qobject_input_end_struct qobject_input_end_struct_x86_64