Code drop from //branches/cupcake/...@124589

1 files changed, 107 insertions, 0 deletions

diff --git a/dynlink.h b/dynlink.h
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+/* Copyright (c) 2008 The Android Open Source Project
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/*
+ * Lazy Dynamic Linking Support
+ *
+ * This header file is meant to be included multiple times.
+ *
+ * It is used to define function pointers to symbols in external
+ * shared objects (Unix dynamic libraries) which will be lazily resolved
+ * at runtime, by calling a specific initialization function.
+ *
+ * You must define, before including this header, a DYNLINK_FUNCTIONS
+ * macro which must contain a sequence of DYNLINK_FUNC(ret,name,sig)
+ * statements.
+ *
+ * In each statement, 'ret' is a function return type, 'name' is
+ * the function's name as provided by the library, and 'sig' is
+ * the function signature, including enclosing parentheses.
+ *
+ * Here's an example:
+ *
+ *  #define DYNLINK_FUNCTIONS \
+ *     DYNLINK_FUNC(int,open,(const char*, int)) \
+ *     DYNLINK_FUNC(int,read,(int,char*,int)) \
+ *     DYNLINK_FUNC(int,close,(int)) \
+ *
+ *
+ * You must also define a DYNLINK_FUNCTIONS_INIT macro which contains the
+ * name of a generated function used to initialize the function pointers.
+ * (see below)
+ */
+
+#ifndef DYNLINK_FUNCTIONS
+#error DYNLINK_FUNCTIONS should be defined when including this file
+#endif
+
+#ifndef DYNLINK_FUNCTIONS_INIT
+#error DYNLINK_FUNCTIONS_INIT should be defined when including this file
+#endif
+
+/* just in case */
+#undef DYNLINK_FUNC
+
+/* define pointers to dynamic library functions as static pointers.
+ */
+#define  DYNLINK_FUNC(ret,name,sig) \
+      static ret  (*_dynlink_##name) sig ;
+
+DYNLINK_FUNCTIONS
+#undef DYNLINK_FUNC
+
+/* now define a function that tries to load all dynlink function
+ * pointers. returns 0 on success, or -1 on error (i.e. if any of
+ * the functions could not be loaded).
+ *
+ * 'library' must be the result of a succesful dlopen() call
+ *
+ * You must define DYNLINK_FUNCTIONS_INIT
+ */
+static int
+DYNLINK_FUNCTIONS_INIT(void*  library)
+{
+#define  DYNLINK_FUNC(ret,name,sig) \
+    do { \
+        _dynlink_##name = dlsym( library, STRINGIFY(name) ); \
+        if (_dynlink_##name == NULL) goto Fail; \
+    } while (0);
+
+    DYNLINK_FUNCTIONS
+#undef DYNLINK_FUNC
+
+    return 0;
+Fail:
+    return -1;
+}
+
+/* in user code, use  FF(function_name) to invoke the
+ * corresponding dynamic function named 'function_name'
+ * after initialization succeeded.
+ */
+#ifndef FF
+#define FF(name)   (*_dynlink_##name)
+#endif
+
+/* clear macros */
+#undef DYNLINK_FUNC
+#undef DYNLINK_FUNCTIONS
+#undef DYNLINK_FUNCTIONS_INIT