A Key is the essential class that encapsulates key name , value and metainfo .
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#include <key.hpp>
A Key is the essential class that encapsulates key name , value and metainfo .
To use them:
Key properties are:
- ABI
- Due to ABI compatibility, the
Key structure is not defined in kdb.h, only declared. So you can only declare pointers to Keys in your program, and allocate and free memory for them with keyNew() and keyDel() respectively.
- Reference Counting
- Every key has its reference counter (see keyGetRef() for longer explanation) that will be initialized with 0, that means a subsequent call of keyDel() will delete the key. If you append the key to a keyset the reference counter will be incremented by one (see keyIncRef()) and the key can't be be deleted by a keyDel().
- As you can imagine this refcounting allows you to put the Key in your own datastructures. It can be a very powerful feature, e.g. if you need your own-defined ordering or different Models of your configuration.
This class is an wrapper for an optional, refcounted ckdb::Key. It is like an shared_ptr<ckdb::Key>, but the shared_ptr functionality is already within the Key and exposed with this wrapper.
- optional
- A key can be constructed with an null pointer, by using Key (static_cast<ckdb::Key*>(0)); or made empty afterwards by using release() or assign a null key. To check if there is an associated managed object the user can use operator bool().
- references
- Copies of keys are cheap because they are only flat. If you really need a deep copy, you can use copy() or dup(). If you release() an object, the reference counter will stay All other operations operate on references.
- documentation
- Note that the documentation is typically copied from the underlying function which is wrapped and sometimes extended with C++ specific details. So you might find C examples within the C++ documentation.
- Invariant
- Key either has a working underlying Elektra Key object or a null pointer. The Key, however, might be invalid (see isValid()) or null (see operator bool()).
- Note
- that the reference counting in the keys is mutable, so that const keys can be passed around by value.
Constructs an empty, invalid key.
- Note
- That this is not a null key, so the key will evaluate to true.
- See Also
- isValid(), operator bool()
| kdb::Key::Key |
( |
ckdb::Key * |
k | ) |
|
|
inline |
Constructs a key out of a C key.
- Note
- If you pass a null pointer here, the key will evaluate to false.
- Parameters
-
- See Also
- isValid(), operator bool()
Takes a reference of another key.
The key will not be copied, but the reference counter will be increased.
- Parameters
-
| kdb::Key::Key |
( |
Key const & |
k | ) |
|
|
inline |
Takes a reference of another key.
The key will not be copied, but the reference counter will be increased.
- Parameters
-
| kdb::Key::Key |
( |
const char * |
keyName, |
|
|
|
... |
|
) |
| |
|
inlineexplicit |
A practical way to fully create a Key object in one step.To just get a key object, simple do:
If you want the key object to contain a name, value, comment and other meta info read on.
- Note
- When you already have a key with similar properties its easier to keyDup() the key.
You can call it in many different ways depending on the attribute tags you pass as parameters. Tags are represented as the keyswitch_t values, and tell keyNew() which Key attribute comes next.We can also give an empty key name and a KEY_END tag with the same effect as before:
But we can also give the key a proper name right from the start:
So, keyNew() allocates memory for a key object and keyDel() cleans everything up.keyNew() processes the given argument list even further. The Key attribute tags are the following:
- KEY_VALUE
Next parameter is a pointer to the value that will be used. If no KEY_BINARY was used before, * a string is assumed.
- KEY_SIZE
Define a maximum length of the value. This is only used when setting a binary key.
- KEY_BINARY
Allows to change the key to a binary key. Make sure that you also pass KEY_SIZE before you set the value. Otherwise it will be cut off with first \0 in the string. So this value toggle from keySetString() to keySetBinary().
- KEY_META
Next two parameter is a meta name and a meta value. See keySetMeta().
- KEY_END
Must be the last parameter passed to keyNew(). It is always required, unless the keyName is 0.
- Deprecated:
- These other flags deprecated and KEY_META should be preferred. They remain some time, however, for compatibility:
- Parameters
-
| name | a valid name to the key, or NULL to get a simple initialized, but really empty, object |
- See Also
- keyDel()
- Returns
- a pointer to a new allocated and initialized Key object.
- Return values
-
| NULL | on malloc error or if an invalid name was passed (see keySetName()). |
- Exceptions
-
| KeyInvalidName | if key could not be constructed (typically name wrong or at runtime on allocation problems) |
- Parameters
-
| keyName | the name of the new key |
| kdb::Key::Key |
( |
const std::string |
keyName, |
|
|
|
... |
|
) |
| |
|
inlineexplicit |
A practical way to fully create a Key object in one step.To just get a key object, simple do:
If you want the key object to contain a name, value, comment and other meta info read on.
- Note
- When you already have a key with similar properties its easier to keyDup() the key.
You can call it in many different ways depending on the attribute tags you pass as parameters. Tags are represented as the keyswitch_t values, and tell keyNew() which Key attribute comes next.We can also give an empty key name and a KEY_END tag with the same effect as before:
But we can also give the key a proper name right from the start:
So, keyNew() allocates memory for a key object and keyDel() cleans everything up.keyNew() processes the given argument list even further. The Key attribute tags are the following:
- KEY_VALUE
Next parameter is a pointer to the value that will be used. If no KEY_BINARY was used before, * a string is assumed.
- KEY_SIZE
Define a maximum length of the value. This is only used when setting a binary key.
- KEY_BINARY
Allows to change the key to a binary key. Make sure that you also pass KEY_SIZE before you set the value. Otherwise it will be cut off with first \0 in the string. So this value toggle from keySetString() to keySetBinary().
- KEY_META
Next two parameter is a meta name and a meta value. See keySetMeta().
- KEY_END
Must be the last parameter passed to keyNew(). It is always required, unless the keyName is 0.
- Deprecated:
- These other flags deprecated and KEY_META should be preferred. They remain some time, however, for compatibility:
- Parameters
-
| name | a valid name to the key, or NULL to get a simple initialized, but really empty, object |
- See Also
- keyDel()
- Returns
- a pointer to a new allocated and initialized Key object.
- Return values
-
| NULL | on malloc error or if an invalid name was passed (see keySetName()). |
- Exceptions
-
| KeyInvalidName | if key could not be constructed (typically name wrong or at runtime on allocation problems) |
- Warning
- Not supported on some compilers, e.g. clang which require you to only pass non-POD in varg lists.
- Parameters
-
| keyName | the name of the new key |
| kdb::Key::Key |
( |
const char * |
keyName, |
|
|
va_list |
ap |
|
) |
| |
|
inlineexplicit |
A practical way to fully create a Key object in one step.To just get a key object, simple do:
If you want the key object to contain a name, value, comment and other meta info read on.
- Note
- When you already have a key with similar properties its easier to keyDup() the key.
You can call it in many different ways depending on the attribute tags you pass as parameters. Tags are represented as the keyswitch_t values, and tell keyNew() which Key attribute comes next.We can also give an empty key name and a KEY_END tag with the same effect as before:
But we can also give the key a proper name right from the start:
So, keyNew() allocates memory for a key object and keyDel() cleans everything up.keyNew() processes the given argument list even further. The Key attribute tags are the following:
- KEY_VALUE
Next parameter is a pointer to the value that will be used. If no KEY_BINARY was used before, * a string is assumed.
- KEY_SIZE
Define a maximum length of the value. This is only used when setting a binary key.
- KEY_BINARY
Allows to change the key to a binary key. Make sure that you also pass KEY_SIZE before you set the value. Otherwise it will be cut off with first \0 in the string. So this value toggle from keySetString() to keySetBinary().
- KEY_META
Next two parameter is a meta name and a meta value. See keySetMeta().
- KEY_END
Must be the last parameter passed to keyNew(). It is always required, unless the keyName is 0.
- Deprecated:
- These other flags deprecated and KEY_META should be preferred. They remain some time, however, for compatibility:
- Parameters
-
| name | a valid name to the key, or NULL to get a simple initialized, but really empty, object |
- See Also
- keyDel()
- Returns
- a pointer to a new allocated and initialized Key object.
- Return values
-
| NULL | on malloc error or if an invalid name was passed (see keySetName()). |
- Exceptions
-
| KeyInvalidName | if key could not be constructed (typically name wrong or at runtime on allocation problems) |
- Parameters
-
| keyName | the name of the new key |
| ap | the variable argument list pointer |
Destructs the key.
- See Also
- del()
| void kdb::Key::addBaseName |
( |
const std::string & |
baseName | ) |
|
|
inline |
Adds a base name for a key
Adds baseName (that will be escaped) to the current key name.A new baseName will be added, no other part of the key name will be affected.Assumes that key is a directory and will append baseName to it. The function adds the path separator for concatenating.So if key has name "system/dir1/dir2" and this method is called with baseName "mykey", the resulting key will have the name "system/dir1/dir2/mykey".When baseName is 0 nothing will happen and the size of the name is returned.The escaping rules apply as in above .A simple example is:
E.g. if you add . it will be escaped:
succeed_if (
keyAddBaseName (k,
".") >= 0,
"could not add a base name");
succeed_if_same_string(
keyName(k),
"system/valid/\\.");
- See Also
- keySetBaseName() to set a base name
-
keySetName() to set a new name.
- Parameters
-
| key | the key object to work with |
| baseName | the string to append to the name |
- Returns
- the size in bytes of the new key name including the ending NULL
-
-1 if the key had no name
-
-1 on NULL pointers
- Return values
-
| -1 | if key was inserted to a keyset before |
- Exceptions
-
| KeyInvalidName | if the name is not valid |
Clears/Invalidates a key.
Afterwards the object is empty again.
- Note
- This is not a null key, so it will evaluate to true. isValid() will, however, be false.
- See Also
- release()
-
isValid(), operator bool()
Key Object Cleaner.Will reset all internal data.After this call you will receive a fresh key.The reference counter will stay unmodified.
- Note
- that you might also clear() all aliases with this operation.
- Returns
- returns 0 on success
-
-1 on null pointer
- Parameters
-
| key | the key object to work with |
| void kdb::Key::copy |
( |
const Key & |
other | ) |
|
|
inline |
Copy or Clear a key.Most often you may prefer keyDup() which allocates a new key and returns a duplication of another key.But when you need to copy into an existing key, e.g. because it was passed by a pointer in a function you can do so:
The reference counter will not be changed for both keys. Affiliation to keysets are also not affected.The meta data will be duplicated for the destination key. So it will not take much additional space, even with lots of metadata.When you pass a NULL-pointer as source the data of dest will be cleaned completely (except reference counter, see keyClear()) and you get a fresh dest key:
If you want to copy everything, except e.g. the value you can use keyCopy() too:
{
char *value = malloc (size);
free (value);
}
Restrain from coping everything yourself, because it will lead to wrong metadata and is not able to copy empty or cascading names:
- Parameters
-
| dest | the key which will be written to |
| source | the key which should be copied or NULL to clean the destination key |
- Returns
- -1 on failure when a NULL pointer was passed for dest or a dynamic property could not be written. Both name and value are empty then.
-
0 when dest was cleaned
-
1 when source was successfully copied
- See Also
- keyDup() to get a duplication of a Key
| void kdb::Key::copyAllMeta |
( |
const Key & |
other | ) |
|
|
inline |
Do a shallow copy of all meta data from source to dest.The key dest will additionally have all meta data the source had. Meta data not present in source will not be changed. Meta data which was present in source and dest will be overwritten.For example the meta data type is copied into the Key k:
The main purpose of this function is for plugins or applications which want to add the same meta data to n keys. When you do that with keySetMeta() it will take n times the memory for the key. This can be considerable amount of memory for many keys with some meta data for each.To avoid that problem you can use keyCopyAllMeta() or keyCopyMeta():
void o(KeySet *ks)
{
keySetMeta(shared,
"shared1",
"this meta data should be shared among many keys");
keySetMeta(shared,
"shared2",
"this meta data should be shared among many keys also");
keySetMeta(shared,
"shared3",
"this meta data should be shared among many keys too");
while ((current =
ksNext(ks)) != 0)
{
}
}
- Postcondition
- for every metaName present in source: keyGetMeta(source, metaName) == keyGetMeta(dest, metaName)
- Returns
- 1 if was successfully copied
-
0 if source did not have any meta data
-
-1 on null pointer of dest or source
-
-1 on memory problems
- Parameters
-
| dest | the destination where the meta data should be copied too |
| source | the key where the meta data should be copied from |
- See Also
- getMeta(), setMeta(), copyMeta()
| void kdb::Key::copyMeta |
( |
const Key & |
other, |
|
|
const std::string & |
metaName |
|
) |
| |
|
inline |
Do a shallow copy of meta data from source to dest.The key dest will have the same meta data referred with metaName afterwards then source.For example the meta data type is copied into the Key k.
The main purpose of this function is for plugins or applications which want to add the same meta data to n keys. When you do that with
keySetMeta() it will take n times the memory for the key. This can be considerable amount of memory for many keys with some meta data for each.To avoid that problem you can use
keyCopyAllMeta() or
keyCopyMeta().
void o(KeySet *ks)
{
keySetMeta(shared,
"shared",
"this meta data should be shared among many keys");
while ((current =
ksNext(ks)) != 0)
{
if (needs_shared_data(current))
keyCopyMeta(current, shared,
"shared");
}
}
- Postcondition
- keyGetMeta(source, metaName) == keyGetMeta(dest, metaName)
- Returns
- 1 if was successfully copied
-
0 if the meta data in dest was removed too
-
-1 on null pointers (source or dest)
-
-1 on memory problems
- Parameters
-
| dest | the destination where the meta data should be copied too |
| source | the key where the meta data should be copied from |
| metaName | the name of the meta data which should be copied |
- See Also
- getMeta(), setMeta(), copyAllMeta()
| const Key kdb::Key::currentMeta |
( |
| ) |
const |
|
inline |
Returns the Value of a Meta-Information which is current.The pointer is NULL if you reached the end or after ksRewind().
- Note
- You must not delete or change the returned key, use keySetMeta() if you want to delete or change it.
- Parameters
-
| key | the key object to work with |
- Returns
- a buffer to the value pointed by
key's cursor
-
0 on NULL pointer
- See Also
- keyNextMeta(), keyRewindMeta()
-
ksCurrent() for pedant in iterator interface of KeySet
- Note
- that the key will be null if last meta data is found.
k.rewindMeta();
while (meta = k.nextMeta())
{
cout << meta.getName() << " " << meta.getString() << endl;
}
- See Also
- rewindMeta(), nextMeta()
| void kdb::Key::delMeta |
( |
const std::string & |
metaName | ) |
|
|
inline |
| ckdb::Key * kdb::Key::dup |
( |
| ) |
const |
|
inline |
Return a duplicate of a key.Memory will be allocated as needed for dynamic properties.The new key will not be member of any KeySet and will start with a new reference counter at 0. A subsequent keyDel() will delete the key.
int f (
const Key * source)
{
}
Like for a new key after
keyNew() a subsequent
ksAppend() makes a
KeySet to take care of the lifecycle of the key.
int g (
const Key * source, KeySet * ks)
{
}
Duplication of keys should be preferred to
keyNew(), because data like owner can be filled with a copy of the key instead of asking the environment. It can also be optimized in the checks, because the keyname is known to be valid.
- Parameters
-
| source | has to be an initialized source Key |
- Returns
- 0 failure or on NULL pointer
-
a fully copy of source on success
- See Also
- ksAppend(), keyDel(), keyNew()
| std::string kdb::Key::get |
( |
| ) |
const |
|
inline |
Get a key value.
You can write your own template specialication, e.g.:
- Returns
- the string directly from the key.
It should be the same as get().
- Returns
- empty string on null pointers
- Exceptions
-
| KeyException | on null key or not a valid size |
| KeyTypeMismatch | if key holds binary data and not a string |
- Note
- unlike in the C version, it is safe to change the returned string.
- See Also
- isString(), getBinary()
This method tries to serialise the string to the given type.
| std::string kdb::Key::getBaseName |
( |
| ) |
const |
|
inline |
Returns a pointer to the internal unescaped key name where the basename starts.
This is a much more efficient version of keyGetBaseName() and you should use it if you are responsible enough to not mess up things. The name might change or even point to a wrong place after a keySetName(). So make sure to copy the memory before the name changes.keyBaseName() returns "" when there is no keyBaseName. The reason is
And there is also support for really empty basenames:
succeed_if (
keyAddBaseName (k,
"") >= 0,
"could not add a base name");
succeed_if_same_string(
keyName(k),
"system/valid/%");
- Note
- You must never use the pointer returned by keyBaseName() method to change the name, but you should use keySetBaseName() instead.
- Parameters
-
| key | the object to obtain the basename from |
- Returns
- a pointer to the basename
-
"" when the key has no (base)name
-
0 on NULL pointer
- See Also
- keyGetBaseName(), keyGetBaseNameSize()
-
keyName() to get a pointer to the name
-
keyOwner() to get a pointer to the owner
| ssize_t kdb::Key::getBaseNameSize |
( |
| ) |
const |
|
inline |
Calculates number of bytes needed to store basename of key.Key names that have only root names (e.g. "system" or "user" or "user:domain" ) does not have basenames, thus the function will return 1 bytes to store "".Basenames are denoted as:
system/some/thing/basename -> basename user:domain/some/thing/base\/name > base\/name
- Parameters
-
| key | the key object to work with |
- Returns
- size in bytes of
key's basename including ending NULL
- See Also
- keyBaseName(), keyGetBaseName()
-
keyName(), keyGetName(), keySetName()
| std::string kdb::Key::getBinary |
( |
| ) |
const |
|
inline |
- Returns
- the binary Value of the key.
- Return values
-
| "" | on null pointers (size == 0) and on data only containing \0 |
- Note
- if you need to distinguish between null pointers and data containing \0 you can use getValue().
- Exceptions
-
| KeyException | on invalid binary size |
| KeyTypeMismatch | if key is string and not a binary |
Get the value of a key as a binary.If the type is not binary -1 will be returned.When the binary data is empty (this is not the same as ""!) 0 will be returned and the returnedBinary will not be changed.For string values see keyGetString() and keyIsString().When the returnedBinary is to small to hold the data (its maximum size is given by maxSize), the returnedBinary will not be changed and -1 is returned.
- Example:
- Parameters
-
| key | the object to gather the value from |
| returnedBinary | pre-allocated memory to store a copy of the key value |
| maxSize | number of bytes of pre-allocated memory in returnedBinary |
- Returns
- the number of bytes actually copied to
returnedBinary
- Return values
-
| 0 | if the binary is empty |
| -1 | on NULL pointers |
| -1 | if maxSize is 0 |
| -1 | if maxSize is too small for string |
| -1 | if maxSize is larger than SSIZE_MAX |
| -1 | on type mismatch: binary expected, but found string |
- See Also
- keyValue(), keyGetValueSize(), keySetBinary()
-
keyGetString() and keySetString() as preferred alternative to binary
-
keyIsBinary() to see how to check for binary type
- See Also
- isBinary(), getString(), getValue()
| ssize_t kdb::Key::getBinarySize |
( |
| ) |
const |
|
inline |
Returns the number of bytes needed to store the key value, including the NULL terminator.It returns the correct size, independent of the Key Type. If it is a binary there might be '\0' values in it.For an empty string you need one byte to store the ending NULL. For that reason 1 is returned. This is not true for binary data, so there might be returned 0 too.A binary key has no '\0' termination. String types have it, so to there length will be added 1 to have enough space to store it.This method can be used with malloc() before keyGetString() or keyGetBinary() is called.
- Parameters
-
| key | the key object to work with |
- Returns
- the number of bytes needed to store the key value
-
1 when there is no data and type is not binary
-
0 when there is no data and type is binary
-
-1 on null pointer
- See Also
- keyGetString(), keyGetBinary(), keyValue()
| std::string kdb::Key::getDirName |
( |
| ) |
const |
|
inline |
- Returns
- the dir name of the key
e.g. system/sw/dir/key will return system/sw/dir
| std::string kdb::Key::getFullName |
( |
| ) |
const |
|
inline |
Get key full name, including the user domain name.
- Returns
- number of bytes written
-
1 on empty name
-
-1 on NULL pointers
-
-1 if maxSize is 0 or larger than SSIZE_MAX
- Parameters
-
| key | the key object |
| returnedName | pre-allocated memory to write the key name |
| maxSize | maximum number of bytes that will fit in returnedName, including the final NULL |
- Exceptions
-
| KeyException | if key is null |
| ssize_t kdb::Key::getFullNameSize |
( |
| ) |
const |
|
inline |
Bytes needed to store the key name including user domain and ending NULL.
- Parameters
-
| key | the key object to work with |
- Returns
- number of bytes needed to store key name including user domain
-
1 on empty name
-
-1 on NULL pointer
- See Also
- keyGetFullName(), keyGetNameSize()
| Key::func_t kdb::Key::getFunc |
( |
| ) |
const |
|
inline |
Elektra can store function pointers as binary. This function returns such a function pointer.
- Exceptions
-
| KeyTypeMismatch | if no binary data found, or binary data has not correct length |
- Returns
- a function pointer stored with setBinary()
| ckdb::Key * kdb::Key::getKey |
( |
| ) |
const |
|
inline |
Passes out the raw key pointer.
This pointer can be used to directly change the underlying key object.
- Note
- that the ownership remains in the object
| std::string kdb::Key::getMeta |
( |
const std::string & |
metaName | ) |
const |
|
inline |
Returns the Value of a Meta-Information given by name.This is a much more efficient version of keyGetMeta(). But unlike with keyGetMeta you are not allowed to modify the resulting string.
- Note
- You must not delete or change the returned key, use keySetMeta() if you want to delete or change it.
- Parameters
-
| key | the key object to work with |
| metaName | the name of the meta information you want the value from |
- Returns
- 0 if the key or metaName is 0
-
0 if no such metaName is found
-
value of Meta-Information if Meta-Information is found
- See Also
- keyGetMeta(), keySetMeta()
You can specify your own template specialisation:
template<>
{
yourtype x;
std::string str;
str = std::string(
static_cast<const char*>(
)
)
);
return yourconversion(str);
}
- Exceptions
-
| KeyTypeConversion | if meta data could not be parsed |
- Note
- No exception will be thrown if a const Key or char* is requested, but don't forget the const: getMeta<const Key>, otherwise you will get an compiler error.
If no meta is available:
| std::string kdb::Key::getName |
( |
| ) |
const |
|
inline |
Returns a pointer to the abbreviated real internal key name.This is a much more efficient version of keyGetName() and can use it if you are responsible enough to not mess up things. You are not allowed to change anything in the returned array. The content of that string may change after keySetName() and similar functions. If you need a copy of the name, consider using keyGetName().The name will be without owner, see keyGetFullName() if you need the name with its owner.keyName() returns "" when there is no keyName. The reason is
- Note
- Note that the Key structure keeps its own size field that is calculated by library internal calls, so to avoid inconsistencies, you must never use the pointer returned by keyName() method to set a new value. Use keySetName() instead.
- Parameters
-
| key | the key object to work with |
- Returns
- a pointer to the keyname which must not be changed.
-
"" when there is no (a empty) keyname
-
0 on NULL pointer
- See Also
- keyGetNameSize() for the string length
-
keyGetFullName(), keyGetFullNameSize() to get the full name
-
keyGetName() as alternative to get a copy
-
keyOwner() to get a pointer to owner
- Note
- unlike in the C version, it is safe to change the returned string.
| ssize_t kdb::Key::getNameSize |
( |
| ) |
const |
|
inline |
Bytes needed to store the key name without owner.For an empty key name you need one byte to store the ending NULL. For that reason 1 is returned.
- Parameters
-
| key | the key object to work with |
- Returns
- number of bytes needed, including ending NULL, to store key name without owner
-
1 if there is is no key Name
-
-1 on NULL pointer
- See Also
- keyGetName(), keyGetFullNameSize()
| ssize_t kdb::Key::getReferenceCounter |
( |
| ) |
const |
|
inline |
Return how many references the key has.The reference counting is the essential property of keys to make sure that they can be put safely into data structures. E.g. if you put a Key into a KeySet:
KeySet *ks =
ksNew (1, k, KS_END);
You can even add the key to more KeySets:
KeySet *ks1 =
ksNew(1, k, KS_END);
KeySet *ks2 =
ksNew(1, k, KS_END);
If you increment only by one with keyIncRef() the same as said above is valid:
or use keyIncRef() more than once:
The key won't be deleted by a keyDel() as long refcounter is not 0.The references will be incremented on successful calls to ksAppendKey() or ksAppend().
- Note
- keyDup() will reset the references for dupped key.
For your own applications you can use keyIncRef() and keyDecRef() for reference counting, too.
- Parameters
-
| key | the key object to work with |
- Returns
- the number of references
-
-1 on null pointer
- See Also
- keyIncRef() and keyDecRef()
| std::string kdb::Key::getString |
( |
| ) |
const |
|
inline |
- Returns
- the string directly from the key.
It should be the same as get().
- Returns
- empty string on null pointers
- Exceptions
-
| KeyException | on null key or not a valid size |
| KeyTypeMismatch | if key holds binary data and not a string |
- Note
- unlike in the C version, it is safe to change the returned string.
- See Also
- isString(), getBinary()
| ssize_t kdb::Key::getStringSize |
( |
| ) |
const |
|
inline |
Returns the number of bytes needed to store the key value, including the NULL terminator.It returns the correct size, independent of the Key Type. If it is a binary there might be '\0' values in it.For an empty string you need one byte to store the ending NULL. For that reason 1 is returned. This is not true for binary data, so there might be returned 0 too.A binary key has no '\0' termination. String types have it, so to there length will be added 1 to have enough space to store it.This method can be used with malloc() before keyGetString() or keyGetBinary() is called.
- Parameters
-
| key | the key object to work with |
- Returns
- the number of bytes needed to store the key value
-
1 when there is no data and type is not binary
-
0 when there is no data and type is binary
-
-1 on null pointer
- See Also
- keyGetString(), keyGetBinary(), keyValue()
| const void * kdb::Key::getValue |
( |
| ) |
const |
|
inline |
Return a pointer to the real internal key value.This is a much more efficient version of keyGetString() keyGetBinary(), and you should use it if you are responsible enough to not mess up things. You are not allowed to modify anything in the returned string. If you need a copy of the Value, consider to use keyGetString() or keyGetBinary() instead.
- Returns
- the value of the key
- See Also
- getBinary()
| bool kdb::Key::hasMeta |
( |
const std::string & |
metaName | ) |
const |
|
inline |
- Return values
-
| true | if there is a metadata with given name |
| false | if no such metadata exists |
- See Also
- getMeta()
| bool kdb::Key::isBelow |
( |
const Key & |
k | ) |
const |
|
inline |
- Parameters
-
- Returns
- true if our key is below k
Check if the key check is below the key key or not.Example:
key user/sw/app
check user/sw/app/key
returns true because check is below keyExample:
key user/sw/app
check user/sw/app/folder/key
returns also true because check is indirect below key
- Parameters
-
| key | the key object to work with |
| check | the key to find the relative position of |
- Returns
- 1 if check is below key
-
0 if it is not below or if it is the same key
- See Also
- keySetName(), keyGetName(), keyIsDirectBelow()
| bool kdb::Key::isBelowOrSame |
( |
const Key & |
k | ) |
const |
|
inline |
- Parameters
-
- Returns
- true if our key is below k or the same as k
| bool kdb::Key::isBinary |
( |
| ) |
const |
|
inline |
Check if a key is binary type.The function checks if the key is a binary. Opposed to string values binary values can have '\0' inside the value and may not be terminated by a null character. Their disadvantage is that you need to pass their size.Make sure to use this function and don't test the binary type another way to ensure compatibility and to write less error prone programs.
- Returns
- 1 if it is binary
-
0 if it is not
-
-1 on NULL pointer
- See Also
- keyGetBinary(), keySetBinary()
- Parameters
-
| bool kdb::Key::isDirectBelow |
( |
const Key & |
k | ) |
const |
|
inline |
- Parameters
-
- Returns
- true if our key is direct below k
Check if the key check is direct below the key key or not.
Example:
key user/sw/app
check user/sw/app/key
returns true because check is below key
Example:
key user/sw/app
check user/sw/app/folder/key
does not return true, because there is only a indirect relation
- Parameters
-
| key | the key object to work with |
| check | the key to find the relative position of |
- Returns
- 1 if check is below key
-
0 if it is not below or if it is the same key
-
-1 on null pointer
- See Also
- keyIsBelow(), keySetName(), keyGetName()
| bool kdb::Key::isInactive |
( |
| ) |
const |
|
inline |
Check whether a key is inactive.In Elektra terminology a hierarchy of keys is inactive if the rootkey's basename starts with '.'. So a key is also inactive if it is below an inactive key. For example, user/key/.hidden is inactive and so is user/.hidden/below.Inactive keys should not have any meaning to applications, they are only a convention reserved for users and administrators. To automatically remove all inactive keys for an application, consider to use the hidden plugin.
- Parameters
-
| key | the key object to work with |
- Return values
-
| 1 | if the key is inactive |
| 0 | if the key is active |
| -1 | on NULL pointer or when key has no name |
| bool kdb::Key::isString |
( |
| ) |
const |
|
inline |
Check if a key is string type.String values are null terminated and are not allowed to have any '\0' characters inside the string.Make sure to use this function and don't test the string type another way to ensure compatibility and to write less error prone programs.
- Returns
- 1 if it is string
-
0 if it is not
-
-1 on NULL pointer
- See Also
- keyGetString(), keySetString()
- Parameters
-
| bool kdb::Key::isSystem |
( |
| ) |
const |
|
inline |
Name starts with "system".
- Return values
-
| true | if it is a system key |
| false | otherwise |
| bool kdb::Key::isUser |
( |
| ) |
const |
|
inline |
Name starts with "user".
- Return values
-
| true | if it is a user key |
| false | otherwise |
| bool kdb::Key::isValid |
( |
| ) |
const |
|
inline |
- Returns
- if the key is valid
An invalid key has no name. The name of valid keys either start with user or system.
- Return values
-
| true | if the key has a valid name |
| false | if the key has an invalid name |
- See Also
- getName(), isUser(), isSystem()
| const Key kdb::Key::nextMeta |
( |
| ) |
|
|
inline |
Iterate to the next meta information.Keys have an internal cursor that can be reset with keyRewindMeta(). Every time keyNextMeta() is called the cursor is incremented and the new current Name of Meta Information is returned.You'll get a NULL pointer if the meta information after the end of the Key was reached. On subsequent calls of keyNextMeta() it will still return the NULL pointer.The key internal cursor will be changed, so it is not const.
- Note
- That the resulting key is guaranteed to have a value, because meta information has no binary or null pointer semantics.
-
You must not delete or change the returned key, use keySetMeta() if you want to delete or change it.
- Parameters
-
| key | the key object to work with |
- Returns
- a key representing meta information
-
0 when the end is reached
-
0 on NULL pointer
- See Also
- ksNext() for pedant in iterator interface of KeySet
- See Also
- rewindMeta(), currentMeta()
| kdb::Key::operator bool |
( |
| ) |
const |
|
inline |
This is for loops and lookups only.
For loops it checks if there are still more keys. For lookups it checks if a key could be found.
- Warning
- you should not construct or use null keys
- Returns
- false on null keys
-
true otherwise
| bool kdb::Key::operator!= |
( |
const Key & |
k | ) |
const |
|
inline |
Compare the name of two keys.
- Returns
- a number less than, equal to or greater than zero if k1 is found, respectively, to be less than, to match, or be greater than k2.
The comparison is based on a strcmp of the keynames, and iff they match a strcmp of the owner will be used to distuingish. If even this matches the keys are found to be exactly the same and 0 is returned. These two keys can't be used in the same KeySet.keyCmp() defines the sorting order for a KeySet.The following 3 points are the rules for null values:
- A null pointer will be found to be smaller than every other key. If both are null pointers, 0 is returned.
- A null name will be found to be smaller than every other name. If both are null names, 0 is returned.
If the name is equal then:
- No owner will be found to be smaller then every other owner. If both don't have a owner, 0 is returned.
- Note
- the owner will only be used if the names are equal.
Often is enough to know if the other key is less then or greater then the other one. But Sometimes you need more precise information, see keyRel().Given any Keys k1 and k2 constructed with keyNew(), following equation hold true:
Here are some more examples:
And even more:
Do not strcmp the
keyName() yourself because the result differs from simple ascii comparison.
- Parameters
-
| k1 | the first key object to compare with |
| k2 | the second key object to compare with |
- See Also
- ksAppendKey(), ksAppend() will compare keys when appending
-
ksLookup() will compare keys during searching
- Return values
-
| ckdb::Key * kdb::Key::operator* |
( |
| ) |
const |
|
inline |
Is a abbreviation for getKey.
Passes out the raw key pointer.This pointer can be used to directly change the underlying key object.
- Note
- that the ownership remains in the object
- See Also
- getKey()
| void kdb::Key::operator++ |
( |
int |
| ) |
const |
|
inline |
Increment the viability of a key object.This function is intended for applications using their own reference counter for key objects. With it you can increment the reference and thus avoid destruction of the object in a subsequent keyDel().The reference counter can't be incremented once it reached SSIZE_MAX. In that situation nothing will happen and SSIZE_MAX will be returned.
- Note
- keyDup() will reset the references for dupped key.
- Returns
- the value of the new reference counter
-
-1 on null pointer
-
SSIZE_MAX when maximum exceeded
- Parameters
-
| key | the key object to work with |
- See Also
- keyGetRef() for longer explanation, keyDecRef(), keyDel()
| void kdb::Key::operator++ |
( |
| ) |
const |
|
inline |
Increment the viability of a key object.This function is intended for applications using their own reference counter for key objects. With it you can increment the reference and thus avoid destruction of the object in a subsequent keyDel().The reference counter can't be incremented once it reached SSIZE_MAX. In that situation nothing will happen and SSIZE_MAX will be returned.
- Note
- keyDup() will reset the references for dupped key.
- Returns
- the value of the new reference counter
-
-1 on null pointer
-
SSIZE_MAX when maximum exceeded
- Parameters
-
| key | the key object to work with |
- See Also
- keyGetRef() for longer explanation, keyDecRef(), keyDel()
| void kdb::Key::operator-- |
( |
int |
| ) |
const |
|
inline |
Decrement the viability of a key object.The references will be decremented for ksPop() or successful calls of ksLookup() with the option KDB_O_POP. It will also be decremented with an following keyDel() in the case that an old key is replaced with another key with the same name.The reference counter can't be decremented once it reached 0. In that situation nothing will happen and 0 will be returned.
- Note
- keyDup() will reset the references for dupped key.
- Returns
- the value of the new reference counter
-
-1 on null pointer
-
0 when the key is ready to be freed
- Parameters
-
| key | the key object to work with |
- See Also
- keyGetRef() for longer explanation, keyDel(), keyIncRef()
| void kdb::Key::operator-- |
( |
| ) |
const |
|
inline |
Decrement the viability of a key object.The references will be decremented for ksPop() or successful calls of ksLookup() with the option KDB_O_POP. It will also be decremented with an following keyDel() in the case that an old key is replaced with another key with the same name.The reference counter can't be decremented once it reached 0. In that situation nothing will happen and 0 will be returned.
- Note
- keyDup() will reset the references for dupped key.
- Returns
- the value of the new reference counter
-
-1 on null pointer
-
0 when the key is ready to be freed
- Parameters
-
| key | the key object to work with |
- See Also
- keyGetRef() for longer explanation, keyDel(), keyIncRef()
| Key * kdb::Key::operator-> |
( |
| ) |
|
|
inline |
| bool kdb::Key::operator< |
( |
const Key & |
other | ) |
const |
|
inline |
Compare the name of two keys.
- Returns
- a number less than, equal to or greater than zero if k1 is found, respectively, to be less than, to match, or be greater than k2.
The comparison is based on a strcmp of the keynames, and iff they match a strcmp of the owner will be used to distuingish. If even this matches the keys are found to be exactly the same and 0 is returned. These two keys can't be used in the same KeySet.keyCmp() defines the sorting order for a KeySet.The following 3 points are the rules for null values:
- A null pointer will be found to be smaller than every other key. If both are null pointers, 0 is returned.
- A null name will be found to be smaller than every other name. If both are null names, 0 is returned.
If the name is equal then:
- No owner will be found to be smaller then every other owner. If both don't have a owner, 0 is returned.
- Note
- the owner will only be used if the names are equal.
Often is enough to know if the other key is less then or greater then the other one. But Sometimes you need more precise information, see keyRel().Given any Keys k1 and k2 constructed with keyNew(), following equation hold true:
Here are some more examples:
And even more:
Do not strcmp the
keyName() yourself because the result differs from simple ascii comparison.
- Parameters
-
| k1 | the first key object to compare with |
| k2 | the second key object to compare with |
- See Also
- ksAppendKey(), ksAppend() will compare keys when appending
-
ksLookup() will compare keys during searching
- Return values
-
| bool kdb::Key::operator<= |
( |
const Key & |
other | ) |
const |
|
inline |
Compare the name of two keys.
- Returns
- a number less than, equal to or greater than zero if k1 is found, respectively, to be less than, to match, or be greater than k2.
The comparison is based on a strcmp of the keynames, and iff they match a strcmp of the owner will be used to distuingish. If even this matches the keys are found to be exactly the same and 0 is returned. These two keys can't be used in the same KeySet.keyCmp() defines the sorting order for a KeySet.The following 3 points are the rules for null values:
- A null pointer will be found to be smaller than every other key. If both are null pointers, 0 is returned.
- A null name will be found to be smaller than every other name. If both are null names, 0 is returned.
If the name is equal then:
- No owner will be found to be smaller then every other owner. If both don't have a owner, 0 is returned.
- Note
- the owner will only be used if the names are equal.
Often is enough to know if the other key is less then or greater then the other one. But Sometimes you need more precise information, see keyRel().Given any Keys k1 and k2 constructed with keyNew(), following equation hold true:
Here are some more examples:
And even more:
Do not strcmp the
keyName() yourself because the result differs from simple ascii comparison.
- Parameters
-
| k1 | the first key object to compare with |
| k2 | the second key object to compare with |
- See Also
- ksAppendKey(), ksAppend() will compare keys when appending
-
ksLookup() will compare keys during searching
- Return values
-
| Key & kdb::Key::operator= |
( |
ckdb::Key * |
k | ) |
|
|
inline |
Assign a C key.
Will call del() on the old key.
| Key & kdb::Key::operator= |
( |
const Key & |
k | ) |
|
|
inline |
Assign a key.
Will call del() on the old key.
| bool kdb::Key::operator== |
( |
const Key & |
k | ) |
const |
|
inline |
Compare the name of two keys.
- Returns
- a number less than, equal to or greater than zero if k1 is found, respectively, to be less than, to match, or be greater than k2.
The comparison is based on a strcmp of the keynames, and iff they match a strcmp of the owner will be used to distuingish. If even this matches the keys are found to be exactly the same and 0 is returned. These two keys can't be used in the same KeySet.keyCmp() defines the sorting order for a KeySet.The following 3 points are the rules for null values:
- A null pointer will be found to be smaller than every other key. If both are null pointers, 0 is returned.
- A null name will be found to be smaller than every other name. If both are null names, 0 is returned.
If the name is equal then:
- No owner will be found to be smaller then every other owner. If both don't have a owner, 0 is returned.
- Note
- the owner will only be used if the names are equal.
Often is enough to know if the other key is less then or greater then the other one. But Sometimes you need more precise information, see keyRel().Given any Keys k1 and k2 constructed with keyNew(), following equation hold true:
Here are some more examples:
And even more:
Do not strcmp the
keyName() yourself because the result differs from simple ascii comparison.
- Parameters
-
| k1 | the first key object to compare with |
| k2 | the second key object to compare with |
- See Also
- ksAppendKey(), ksAppend() will compare keys when appending
-
ksLookup() will compare keys during searching
- Return values
-
| bool kdb::Key::operator> |
( |
const Key & |
other | ) |
const |
|
inline |
Compare the name of two keys.
- Returns
- a number less than, equal to or greater than zero if k1 is found, respectively, to be less than, to match, or be greater than k2.
The comparison is based on a strcmp of the keynames, and iff they match a strcmp of the owner will be used to distuingish. If even this matches the keys are found to be exactly the same and 0 is returned. These two keys can't be used in the same KeySet.keyCmp() defines the sorting order for a KeySet.The following 3 points are the rules for null values:
- A null pointer will be found to be smaller than every other key. If both are null pointers, 0 is returned.
- A null name will be found to be smaller than every other name. If both are null names, 0 is returned.
If the name is equal then:
- No owner will be found to be smaller then every other owner. If both don't have a owner, 0 is returned.
- Note
- the owner will only be used if the names are equal.
Often is enough to know if the other key is less then or greater then the other one. But Sometimes you need more precise information, see keyRel().Given any Keys k1 and k2 constructed with keyNew(), following equation hold true:
Here are some more examples:
And even more:
Do not strcmp the
keyName() yourself because the result differs from simple ascii comparison.
- Parameters
-
| k1 | the first key object to compare with |
| k2 | the second key object to compare with |
- See Also
- ksAppendKey(), ksAppend() will compare keys when appending
-
ksLookup() will compare keys during searching
- Return values
-
| bool kdb::Key::operator>= |
( |
const Key & |
other | ) |
const |
|
inline |
Compare the name of two keys.
- Returns
- a number less than, equal to or greater than zero if k1 is found, respectively, to be less than, to match, or be greater than k2.
The comparison is based on a strcmp of the keynames, and iff they match a strcmp of the owner will be used to distuingish. If even this matches the keys are found to be exactly the same and 0 is returned. These two keys can't be used in the same KeySet.keyCmp() defines the sorting order for a KeySet.The following 3 points are the rules for null values:
- A null pointer will be found to be smaller than every other key. If both are null pointers, 0 is returned.
- A null name will be found to be smaller than every other name. If both are null names, 0 is returned.
If the name is equal then:
- No owner will be found to be smaller then every other owner. If both don't have a owner, 0 is returned.
- Note
- the owner will only be used if the names are equal.
Often is enough to know if the other key is less then or greater then the other one. But Sometimes you need more precise information, see keyRel().Given any Keys k1 and k2 constructed with keyNew(), following equation hold true:
Here are some more examples:
And even more:
Do not strcmp the
keyName() yourself because the result differs from simple ascii comparison.
- Parameters
-
| k1 | the first key object to compare with |
| k2 | the second key object to compare with |
- See Also
- ksAppendKey(), ksAppend() will compare keys when appending
-
ksLookup() will compare keys during searching
- Return values
-
| ckdb::Key * kdb::Key::release |
( |
| ) |
|
|
inline |
Passes out the raw key pointer.
- Note
- that the ownership is moved outside.
The key will stay empty.
| void kdb::Key::rewindMeta |
( |
| ) |
const |
|
inline |
template<class T >
| void kdb::Key::set |
( |
T |
x | ) |
|
|
inline |
Set a key value.
Set the value for key as newStringValue.The function will allocate and save a private copy of newStringValue, so the parameter can be freed after the call.String values will be saved in backend storage, when kdbSetKey() will be called, in UTF-8 universal encoding, regardless of the program's current encoding, when iconv plugin is present.
- Note
- The type will be set to KEY_TYPE_STRING. When the type of the key is already a string type it won't be changed.
- Parameters
-
| key | the key to set the string value |
| newStringValue | NULL-terminated text string to be set as key's value |
- Returns
- the number of bytes actually saved in private struct including final NULL
- Return values
-
| 1 | if newStringValue is a NULL pointer, this will make the string empty (string only containing null termination) |
| -1 | if key is a NULL pointer |
- See Also
- keyGetString(), keyValue(), keyString()
This method tries to deserialise the string to the given type.
| void kdb::Key::setBaseName |
( |
const std::string & |
baseName | ) |
|
|
inline |
Sets a base name for a key.
Sets baseName as the new basename for key.Only the baseName will be affected and no other part of the key.All text after the last '/' in the key keyname is erased and baseName is appended.So let us suppose key has name "system/dir1/dir2/key1". If baseName is "key2", the resulting key name will be "system/dir1/dir2/key2". If baseName is empty or NULL, the resulting key name will be "system/dir1/dir2".This function does proper escaping on the supplied name argument.You can use all names to set as basename (e.g. . (dot), .. (dot-dot), % and "" (empty)). They will be properly escaped.A simple example is:
If you do not want escaping, use keySetBaseName() instead. E.g. if you want to add an inactive key, use:
succeed_if_same_string(
keyName(k),
"system/.hiddenkey");
or when you want to add an array item, use:
succeed_if_same_string(
keyName(k),
"system/%");
- See Also
- Name Manipulation Methods for more details on special names
- Parameters
-
| key | the key object to work with |
| baseName | the string used to overwrite the basename of the key |
- Returns
- the size in bytes of the new key name
-
-1 on NULL pointers
- Return values
-
| -1 | if key was inserted to a keyset before |
- See Also
- keyAddBaseName()
-
keySetName() to set a new name
- Exceptions
-
| KeyInvalidName | if the name is not valid |
| ssize_t kdb::Key::setBinary |
( |
const void * |
newBinary, |
|
|
size_t |
dataSize |
|
) |
| |
|
inline |
Set the value of a key as a binary.A private copy of newBinary will allocated and saved inside key, so the parameter can be deallocated after the call.Binary values might be encoded in another way then string values depending on the plugin. Typically character encodings should not take place on binary data. Consider using a string key instead.When newBinary is a NULL pointer the binary will be freed and 0 will be returned.
- Note
- The meta data "binary" will be set to mark that the key is binary from now on. When the key is already binary the meta data won't be changed. This will only happen in the successful case, but not when -1 is returned.
- Parameters
-
| key | the object on which to set the value |
| newBinary | is a pointer to any binary data or NULL to free the previous set data |
| dataSize | number of bytes to copy from newBinary |
- Returns
- the number of bytes actually copied to internal struct storage
-
0 when the internal binary was freed and is now a null pointer
-
-1 if key is a NULL pointer
-
-1 when dataSize is 0 (but newBinary not NULL) or larger than SSIZE_MAX
- See Also
- keyGetBinary()
-
keyIsBinary() to check if the type is binary
-
keyGetString() and keySetString() as preferred alternative to binary
template<class T >
| void kdb::Key::setMeta |
( |
const std::string & |
metaName, |
|
|
T |
x |
|
) |
| |
|
inline |
Set metadata for key.
Set a new Meta-Information.Will set a new Meta-Information pair consisting of metaName and newMetaString.Will add a new Pair for Meta-Information if metaName was not added up to now.It will modify a existing Pair of Meta-Information if the the metaName was inserted already.It will remove a meta information if newMetaString is 0.
- Parameters
-
| key | the key object to work with |
| metaName | the name of the meta information where you want to change the value |
| newMetaString | the new value for the meta information |
- Returns
- -1 on error if key or metaName is 0, out of memory or names are not valid
-
0 if the Meta-Information for metaName was removed
-
size (>0) of newMetaString if Meta-Information was successfully added
- See Also
- keyGetMeta()
- Warning
- unlike the C Interface, it is not possible to remove metadata with this method. k.setMeta("something", NULL) will lead to set the number 0 or to something different (may depend on compiler definition of NULL). See discussion in Issue https://github.com/ElektraInitiative/libelektra/issues/8
Use delMeta() to avoid these issues.
- See Also
- delMeta(), getMeta(), copyMeta(), copyAllMeta()
| void kdb::Key::setName |
( |
const std::string & |
newName | ) |
|
|
inline |
Set a new name to a key.A valid name is of the forms:
system/something user/something user:username/something
The last form has explicitly set the owner, to let the library know in which user folder to save the key. A owner is a user name. If it is not defined (the second form) current user is used.You should always follow the guidelines for key tree structure creation.A private copy of the key name will be stored, and the
newName parameter can be freed after this call..., . and / will be handled as in filesystem pathes. A valid name will be build out of the (valid) name what you pass, e.g. user///sw/../sw//././MyApp -> user/sw/MyAppOn invalid names, NULL or "" the name will be "" afterwards.
- Return values
-
| size | in bytes of this new key name including ending NULL |
| 0 | if newName is an empty string or a NULL pointer (name will be empty afterwards) |
| -1 | if newName is invalid (name will be empty afterwards) |
| -1 | if key was inserted to a keyset before |
- Parameters
-
| key | the key object to work with |
| newName | the new key name |
- See Also
- keyNew(), keySetOwner()
-
keyGetName(), keyGetFullName(), keyName()
-
keySetBaseName(), keyAddBaseName() to manipulate a name
- Exceptions
-
| KeyInvalidName | if the name is not valid |
| void kdb::Key::setString |
( |
std::string |
newString | ) |
|
|
inline |
Set the value for key as newStringValue.The function will allocate and save a private copy of newStringValue, so the parameter can be freed after the call.String values will be saved in backend storage, when kdbSetKey() will be called, in UTF-8 universal encoding, regardless of the program's current encoding, when iconv plugin is present.
- Note
- The type will be set to KEY_TYPE_STRING. When the type of the key is already a string type it won't be changed.
- Parameters
-
| key | the key to set the string value |
| newStringValue | NULL-terminated text string to be set as key's value |
- Returns
- the number of bytes actually saved in private struct including final NULL
- Return values
-
| 1 | if newStringValue is a NULL pointer, this will make the string empty (string only containing null termination) |
| -1 | if key is a NULL pointer |
- See Also
- keyGetString(), keyValue(), keyString()
The documentation for this class was generated from the following file:
