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unity.scopes.PreviewQueryBase
Abstract base class to represent a particular preview. More...
#include <unity/scopes/PreviewQueryBase.h>
Inheritance diagram for unity::scopes::PreviewQueryBase:
src="https://assets.ubuntu.com/v1/9637dfb9-classunity_1_1scopes_1_1_preview_query_base__inherit__graph.png" border="0" alt="Inheritance graph"/>
Public Member Functions | |
| virtual void | run (PreviewReplyProxy const &reply)=0 |
| Called by scopes runtime to start the preview. More... | |
| Result | result () const |
| Get result for this preview request. More... | |
| ActionMetadata | action_metadata () const |
| Get metadata for this preview request. More... | |
| virtual void | cancelled ()=0 |
| Called by the scopes runtime when the query originator cancels a query. More... | |
| bool | valid () const |
| Check whether this query is still valid. More... | |
| unity::scopes::VariantMap | settings () const |
| Returns a dictionary with the scope's current settings. More... | |
Protected Member Functions | |
| PreviewQueryBase (Result const &result, ActionMetadata const &metadata) | |
| Instantiates a PreviewQueryBase. More... | |
Detailed Description
Abstract base class to represent a particular preview.
A scope must return an instance of this class from its implementation of ScopeBase::preview().
- Note
- The constructor of the instance must complete in a timely manner. Do not perform anything in the constructor that might block.
Constructor & Destructor Documentation
|
protected |
Instantiates a PreviewQueryBase.
- Parameters
-
result The result to be previewed. metadata Additional data for the preview.
Member Function Documentation
| ActionMetadata unity::scopes::PreviewQueryBase::action_metadata | ( | ) | const |
Get metadata for this preview request.
- Returns
- search metadata
- Exceptions
-
unity::LogicException if preview metadata was not initialized (the default ctor was used).
| Result unity::scopes::PreviewQueryBase::result | ( | ) | const |
Get result for this preview request.
- Exceptions
-
unity::LogicException if result was not initialized (the default ctor was used).
- Returns
- result
|
pure virtual |
Called by scopes runtime to start the preview.
Your implementation of run() can use the reply proxy to push results for the preview. You can push results from within run(), in which case the preview implicitly completes when run() returns. Alternatively, run() can store the reply proxy and return immediately. In this case, you can use the stored proxy to push results from another thread. It is safe to call push() from multiple threads without synchronization.
The preview completes either when run() returns, or when the last stored reply proxy goes out of scope (whichever happens last).
- Parameters
-
reply The proxy on which to push results for the preview.
Implemented in unity::scopes::qt::QPreviewQueryBaseAPI.