c6ff844d75
find_nth() will be inefficient on a trie. Since find_nth() is only used
internally and only for enumerating properties, we can add a foreach()
function to do this directly.
Signed-off-by: Greg Hackmann <ghackmann@google.com>
(cherry picked from commit 577418403d)
Change-Id: Iaca97d1182ce2c28863ba85241cbb5cf6185eb2f
102 lines
3.8 KiB
C
102 lines
3.8 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _INCLUDE_SYS_SYSTEM_PROPERTIES_H
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#define _INCLUDE_SYS_SYSTEM_PROPERTIES_H
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#include <sys/cdefs.h>
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__BEGIN_DECLS
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typedef struct prop_info prop_info;
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#define PROP_NAME_MAX 32
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#define PROP_VALUE_MAX 92
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/* Look up a system property by name, copying its value and a
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** \0 terminator to the provided pointer. The total bytes
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** copied will be no greater than PROP_VALUE_MAX. Returns
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** the string length of the value. A property that is not
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** defined is identical to a property with a length 0 value.
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*/
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int __system_property_get(const char *name, char *value);
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/* Set a system property by name.
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**/
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int __system_property_set(const char *key, const char *value);
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/* Return a pointer to the system property named name, if it
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** exists, or NULL if there is no such property. Use
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** __system_property_read() to obtain the string value from
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** the returned prop_info pointer.
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**
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** It is safe to cache the prop_info pointer to avoid future
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** lookups. These returned pointers will remain valid for
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** the lifetime of the system.
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*/
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const prop_info *__system_property_find(const char *name);
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/* Read the value of a system property. Returns the length
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** of the value. Copies the value and \0 terminator into
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** the provided value pointer. Total length (including
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** terminator) will be no greater that PROP_VALUE_MAX.
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**
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** If name is nonzero, up to PROP_NAME_MAX bytes will be
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** copied into the provided name pointer. The name will
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** be \0 terminated.
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*/
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int __system_property_read(const prop_info *pi, char *name, char *value);
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/* Return a prop_info for the nth system property, or NULL if
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** there is no nth property. Use __system_property_read() to
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** read the value of this property.
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**
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** Please do not call this method. It only exists to provide
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** backwards compatibility to NDK apps. Its implementation
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** is inefficient and order of results may change from call
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** to call.
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*/
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const prop_info *__system_property_find_nth(unsigned n);
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/* Pass a prop_info for each system property to the provided
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** callback. Use __system_property_read() to read the value
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** of this property.
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**
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** This method is for inspecting and debugging the property
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** system. Please use __system_property_find() instead.
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**
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** Order of results may change from call to call. This is
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** not a bug.
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*/
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int __system_property_foreach(
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void (*propfn)(const prop_info *pi, void *cookie),
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void *cookie);
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__END_DECLS
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#endif
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