There are two useful macros that can be defined before including glib.h that are related to the min required glib version - GLIB_VERSION_MIN_REQUIRED When this is defined, if code uses an API that was deprecated in this version, or older, a compiler warning will be emitted. This alerts maintainers to update their code to whatever new replacement API is now recommended best practice. - GLIB_VERSION_MAX_ALLOWED When this is defined, if code uses an API that was introduced in a version that is newer than the declared version, a compiler warning will be emitted. This alerts maintainers if new code accidentally uses functionality that won't be available on some supported platforms. The GLIB_VERSION_MAX_ALLOWED constant makes it a bit harder to opt in to using specific new APIs with a GLIB_CHECK_VERSION conditional. To workaround this Pragmas can be used to temporarily turn off the -Wdeprecated-declarations compiler warning, while a static inline compat function is implemented. This workaround is illustrated with the implementation of the g_strv_contains method to satisfy the test suite. Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
		
			
				
	
	
		
			117 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			117 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * GLIB Compatibility Functions
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 *
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 * Copyright IBM, Corp. 2013
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 *
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 * Authors:
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 *  Anthony Liguori   <aliguori@us.ibm.com>
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 *  Michael Tokarev   <mjt@tls.msk.ru>
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 *  Paolo Bonzini     <pbonzini@redhat.com>
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2 or later.
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 * See the COPYING file in the top-level directory.
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 *
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 */
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#ifndef QEMU_GLIB_COMPAT_H
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#define QEMU_GLIB_COMPAT_H
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/* Ask for warnings for anything that was marked deprecated in
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 * the defined version, or before. It is a candidate for rewrite.
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 */
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#define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_40
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/* Ask for warnings if code tries to use function that did not
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 * exist in the defined version. These risk breaking builds
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 */
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#define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_40
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
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#include <glib.h>
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/*
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 * Note that because of the GLIB_VERSION_MAX_ALLOWED constant above, allowing
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 * use of functions from newer GLib via this compat header needs a little
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 * trickery to prevent warnings being emitted.
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 *
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 * Consider a function from newer glib-X.Y that we want to use
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 *
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 *    int g_foo(const char *wibble)
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 *
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 * We must define a static inline function with the same signature that does
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 * what we need, but with a "_qemu" suffix e.g.
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 *
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 * static inline void g_foo_qemu(const char *wibble)
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 * {
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 *     #if GLIB_CHECK_VERSION(X, Y, 0)
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 *        g_foo(wibble)
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 *     #else
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 *        g_something_equivalent_in_older_glib(wibble);
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 *     #endif
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 * }
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 *
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 * The #pragma at the top of this file turns off -Wdeprecated-declarations,
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 * ensuring this wrapper function impl doesn't trigger the compiler warning
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 * about using too new glib APIs. Finally we can do
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 *
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 *   #define g_foo(a) g_foo_qemu(a)
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 *
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 * So now the code elsewhere in QEMU, which *does* have the
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 * -Wdeprecated-declarations warning active, can call g_foo(...) as normal,
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 * without generating warnings.
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 */
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static inline gboolean g_strv_contains_qemu(const gchar *const *strv,
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                                            const gchar *str)
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{
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#if GLIB_CHECK_VERSION(2, 44, 0)
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    return g_strv_contains(strv, str);
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#else
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    g_return_val_if_fail(strv != NULL, FALSE);
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    g_return_val_if_fail(str != NULL, FALSE);
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    for (; *strv != NULL; strv++) {
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        if (g_str_equal(str, *strv)) {
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            return TRUE;
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        }
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    }
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    return FALSE;
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#endif
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}
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#define g_strv_contains(a, b) g_strv_contains_qemu(a, b)
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#if defined(_WIN32) && !GLIB_CHECK_VERSION(2, 50, 0)
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/*
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 * g_poll has a problem on Windows when using
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 * timeouts < 10ms, so use wrapper.
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 */
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#define g_poll(fds, nfds, timeout) g_poll_fixed(fds, nfds, timeout)
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gint g_poll_fixed(GPollFD *fds, guint nfds, gint timeout);
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#endif
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#ifndef g_assert_cmpmem
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#define g_assert_cmpmem(m1, l1, m2, l2)                                        \
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    do {                                                                       \
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        gconstpointer __m1 = m1, __m2 = m2;                                    \
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        int __l1 = l1, __l2 = l2;                                              \
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        if (__l1 != __l2) {                                                    \
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            g_assertion_message_cmpnum(                                        \
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                G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC,                   \
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                #l1 " (len(" #m1 ")) == " #l2 " (len(" #m2 "))", __l1, "==",   \
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                __l2, 'i');                                                    \
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        } else if (memcmp(__m1, __m2, __l1) != 0) {                            \
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            g_assertion_message(G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC,   \
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                                "assertion failed (" #m1 " == " #m2 ")");      \
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        }                                                                      \
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    } while (0)
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#endif
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#pragma GCC diagnostic pop
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#endif
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