In essence, namespace behaviors acted as hooks for update operations on
namespaces. Two behaviors were implemented:
- `NamespaceBehavior`: allows the update operation unless it acts on a value
that itself was explicitly marked as constant.
- `ConstNamespaceBehavior`: initially allows insert operations but marks the
individual values as const. Additionally provides a `Freeze()` member
function. After this was called, updates are rejected unless a special
`overrideFrozen` flag is set explicitly.
This marvel of object-oriented programming can be replaced with a simple bool.
This commit basically replaces `Namespace::m_Behavior` with
`Namespace::m_ConstValues` and inlines the behavior functions where they were
called. While doing so, the code was slightly simplified by assuming that
`m_ConstValues` is true if `m_Frozen` is true. This is similar to what the API
allowed in the old code as you could only freeze a `ConstNamespaceBehavior`.
However, this PR moves the `Freeze()` member function and the related
`m_Freeze` member variable to the `Namespace` class. So now the API allows any
namespace to be frozen. The new code also makes sense with the previously
mentioned simplification: a `Namespace` with `m_ConstValues = false` can be
modified without restrictions until `Freeze()` is called. When this is done, it
becomes read-only.
The changes outside of `namespace.*` just adapt the code to the slightly
changed API.
Copying an ObjectLock results in the underlying mutex being unlocked too often.
There's also no good reason for copying a scoped locking class (if at all, it
should be moved).
instead of computing from scratch if they're in the _api package.
For now this changes literally nothing as paths of existing objects still follow
the scheme of paths of new objects which didn't change. Now Icinga only doesn't expect
existing objects at particular paths. However, with the latter in v2.14+ (agent,
satellite) we can just change the path scheme of new objects in v2.16+ (master)
as we wish. The child nodes will just follow the new scheme of paths of new objects.
This prevents the `m_HasMatches` property from being altered simultaneously.
This might seem harmless (since this property can only be set to true by any calling thread),
however, from a technical (C++) point of view, this constitutes a data race.
