tile_cache.cpp¶
file src/app/map/tile_cache.cpp ยท Applications
Memory, disk and network lookup, download queue, failure memory and disk writes of TileCache.
Source src/app/map/tile_cache.cpp
Namespaces¶
| Namespace | Description |
|---|---|
nmeasim::app::map |
The slippy-map view of the desktop application, part of nmeasim::app. |
Summary¶
File-local functions
| Name | Description |
|---|---|
default_user_agent() |
Returns the User-Agent the cache identifies itself with. |
is_not_found() |
Returns whether a finished reply means that the server does not have the tile at all. |
File-local variables
| Name | Description |
|---|---|
kMemoryTiles |
Capacity of the memory cache in tiles; 512 tiles of 256 by 256 pixels take about 128 MiB as 32-bit pixmaps. |
kMaxConcurrentDownloads |
Largest number of downloads running at once, kept low as the tile usage policy asks. |
kTransferTimeoutMs |
Time in milliseconds a download may go without receiving data before it is aborted. |
kMaxRetryDelay |
Longest delay before a failed tile is requested again, however often it failed; long enough to spare the server, short enough that a map left open recovers after an outage. |
File-local functions¶
default_user_agent()¶
QString default_user_agent()
Returns the User-Agent the cache identifies itself with.
Returns QString: NMEASimulatorX/<version> (+<project page>), the form the OpenStreetMap tile usage policy asks for: the application, its version and a way to contact its authors.
Declared in src/app/map/tile_cache.cpp:41
is_not_found()¶
bool is_not_found(const QNetworkReply& reply)
Returns whether a finished reply means that the server does not have the tile at all.
Parameters
| Name | Type | Description |
|---|---|---|
reply |
const QNetworkReply& |
Finished reply. |
Returns bool: true for HTTP 404 (Not Found) and 410 (Gone), which asking again will not change.
Declared in src/app/map/tile_cache.cpp:52
File-local variables¶
kMemoryTiles¶
int kMemoryTiles{512}
Capacity of the memory cache in tiles; 512 tiles of 256 by 256 pixels take about 128 MiB as 32-bit pixmaps.
Declared in src/app/map/tile_cache.cpp:28
kMaxConcurrentDownloads¶
int kMaxConcurrentDownloads{4}
Largest number of downloads running at once, kept low as the tile usage policy asks.
Declared in src/app/map/tile_cache.cpp:30
kTransferTimeoutMs¶
int kTransferTimeoutMs{15000}
Time in milliseconds a download may go without receiving data before it is aborted.
Declared in src/app/map/tile_cache.cpp:32
kMaxRetryDelay¶
std::chrono::milliseconds kMaxRetryDelay{std::chrono::minutes{10}}
Longest delay before a failed tile is requested again, however often it failed; long enough to spare the server, short enough that a map left open recovers after an outage.
Declared in src/app/map/tile_cache.cpp:35