nss/lib/util/nssrwlk.h - Issue 2078763002: Delete bundled copy of NSS and replace with README.

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Issue 2078763002: Delete bundled copy of NSS and replace with README. (Closed) Base URL: https://chromium.googlesource.com/chromium/deps/nss@master

Patch Set: Delete bundled copy of NSS and replace with README. Created 4 years, 6 months ago

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1 /* This Source Code Form is subject to the terms of the Mozilla Public

2 * License, v. 2.0. If a copy of the MPL was not distributed with this

3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

4

5 /*

6 ** File: nsrwlock.h

7 ** Description: API to basic reader-writer lock functions of NSS.

8 ** These are re-entrant reader writer locks; that is,

9 ** If I hold the write lock, I can ask for it and get it again.

10 ** If I hold the write lock, I can also ask for and get a read lock.

11 ** I can then release the locks in any order (read or write).

12 ** I must release each lock type as many times as I acquired it.

13 ** Otherwise, these are normal reader/writer locks.

14 **

15 ** For deadlock detection, locks should be ranked, and no lock may be aquired

16 ** while I hold a lock of higher rank number.

17 ** If you don't want that feature, always use NSS_RWLOCK_RANK_NONE.

18 ** Lock name is for debugging, and is optional (may be NULL)

19 **/

20

21 #ifndef nssrwlk_h___

22 #define nssrwlk_h___

23

24 #include "utilrename.h"

25 #include "prtypes.h"

26 #include "nssrwlkt.h"

27

28 #define NSS_RWLOCK_RANK_NONE 0

29

30 /* SEC_BEGIN_PROTOS */

31 PR_BEGIN_EXTERN_C

32

33 /***********************************************************************

34 ** FUNCTION: NSSRWLock_New

35 ** DESCRIPTION:

36 ** Returns a pointer to a newly created reader-writer lock object.

37 ** INPUTS: Lock rank

38 ** Lock name

39 ** OUTPUTS: void

40 ** RETURN: NSSRWLock*

41 ** If the lock cannot be created because of resource constraints, NULL

42 ** is returned.

43 **

44 ***********************************************************************/

45 extern NSSRWLock* NSSRWLock_New(PRUint32 lock_rank, const char *lock_name);

46

47 /***********************************************************************

48 ** FUNCTION: NSSRWLock_AtomicCreate

49 ** DESCRIPTION:

50 ** Given the address of a NULL pointer to a NSSRWLock,

51 ** atomically initializes that pointer to a newly created NSSRWLock.

52 ** Returns the value placed into that pointer, or NULL.

53 **

54 ** INPUTS: address of NSRWLock pointer

55 ** Lock rank

56 ** Lock name

57 ** OUTPUTS: NSSRWLock*

58 ** RETURN: NSSRWLock*

59 ** If the lock cannot be created because of resource constraints,

60 ** the pointer will be left NULL.

61 **

62 ***********************************************************************/

63 extern NSSRWLock *

64 nssRWLock_AtomicCreate( NSSRWLock ** prwlock,

65 PRUint32 lock_rank,

66 const char * lock_name);

67

68 /***********************************************************************

69 ** FUNCTION: NSSRWLock_Destroy

70 ** DESCRIPTION:

71 ** Destroys a given RW lock object.

72 ** INPUTS: NSSRWLock *lock - Lock to be freed.

73 ** OUTPUTS: void

74 ** RETURN: None

75 ***********************************************************************/

76 extern void NSSRWLock_Destroy(NSSRWLock *lock);

77

78 /***********************************************************************

79 ** FUNCTION: NSSRWLock_LockRead

80 ** DESCRIPTION:

81 ** Apply a read lock (non-exclusive) on a RWLock

82 ** INPUTS: NSSRWLock *lock - Lock to be read-locked.

83 ** OUTPUTS: void

84 ** RETURN: None

85 ***********************************************************************/

86 extern void NSSRWLock_LockRead(NSSRWLock *lock);

87

88 /***********************************************************************

89 ** FUNCTION: NSSRWLock_LockWrite

90 ** DESCRIPTION:

91 ** Apply a write lock (exclusive) on a RWLock

92 ** INPUTS: NSSRWLock *lock - Lock to write-locked.

93 ** OUTPUTS: void

94 ** RETURN: None

95 ***********************************************************************/

96 extern void NSSRWLock_LockWrite(NSSRWLock *lock);

97

98 /***********************************************************************

99 ** FUNCTION: NSSRWLock_UnlockRead

100 ** DESCRIPTION:

101 ** Release a Read lock. Unlocking an unlocked lock has undefined results.

102 ** INPUTS: NSSRWLock *lock - Lock to unlocked.

103 ** OUTPUTS: void

104 ** RETURN: void

105 ***********************************************************************/

106 extern void NSSRWLock_UnlockRead(NSSRWLock *lock);

107

108 /***********************************************************************

109 ** FUNCTION: NSSRWLock_UnlockWrite

110 ** DESCRIPTION:

111 ** Release a Write lock. Unlocking an unlocked lock has undefined results.

112 ** INPUTS: NSSRWLock *lock - Lock to unlocked.

113 ** OUTPUTS: void

114 ** RETURN: void

115 ***********************************************************************/

116 extern void NSSRWLock_UnlockWrite(NSSRWLock *lock);

117

118 /***********************************************************************

119 ** FUNCTION: NSSRWLock_HaveWriteLock

120 ** DESCRIPTION:

121 ** Tells caller whether the current thread holds the write lock, or not.

122 ** INPUTS: NSSRWLock *lock - Lock to test.

123 ** OUTPUTS: void

124 ** RETURN: PRBool PR_TRUE IFF the current thread holds the write lock.

125 ***********************************************************************/

126

127 extern PRBool NSSRWLock_HaveWriteLock(NSSRWLock *rwlock);

128

129 /* SEC_END_PROTOS */

130 PR_END_EXTERN_C

131

132 #endif /* nsrwlock_h___ */

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