479 lines
13 KiB
Markdown
479 lines
13 KiB
Markdown
|
|
# Ox Docs
|
|
|
|
## Project Structure
|
|
|
|
All components have a platform indicator next to them:
|
|
|
|
(OB) - OS, Bare Metal
|
|
(-B) - Bare Metal
|
|
(O-) - OS
|
|
|
|
* Ox - Library of things useful for portable bare metal and userland code. Not really that external...
|
|
* clargs - Command Line Args processing (OB)
|
|
* claw - Reads and writes Metal or Organic Claw with header to indicate which
|
|
* event - Qt-like signal system (OB)
|
|
* fs - file system (OB)
|
|
* logconn - connects logging to Bullock (O-)
|
|
* mc - Metal Claw serialization, builds on model (OB)
|
|
* oc - Organic Claw serialization (wrapper around JsonCpp), builds on model (O-)
|
|
* model - Data structure modelling (OB)
|
|
* preloader - library for handling preloading of data (OB)
|
|
* std - Standard-ish Library with a lot missing and some things added (OB)
|
|
|
|
## Systems
|
|
|
|
### Error Handling
|
|
|
|
Ox provides ```ox::Error``` to report errors.
|
|
```ox::Error``` is a struct that has overloaded operators to behave like an
|
|
integer error code, plus some extra fields to enhance debuggability.
|
|
If instantiated through the ```OxError(x)``` macro, it will also include the
|
|
file and line of the error.
|
|
The ```OxError(x)``` macro should only be used for the initial instantiation of
|
|
an ```ox::Error```.
|
|
|
|
In addition to ```ox::Error``` there is also the template ```ox::Result<T>```.
|
|
```ox::Result``` simply wraps the type T value in a struct that also includes
|
|
error information, which allows the returning of a value and an error without
|
|
resorting to output parameters.
|
|
|
|
If a function returns an ```ox::Error``` or ```ox::Result``` it should be
|
|
declared as ```noexcept``` and all exceptions should be translated to an
|
|
```ox::Error```.
|
|
|
|
```ox::Result``` can be used as follows:
|
|
|
|
```cpp
|
|
ox::Result<int> foo(int i) noexcept {
|
|
if (i < 10) {
|
|
return i + 1; // implicitly calls ox::Result<T>::Result(T)
|
|
}
|
|
return OxError(1); // implicitly calls ox::Result<T>::Result(ox::Error)
|
|
}
|
|
|
|
int caller1() {
|
|
auto v = foo(argc);
|
|
if (v.error) {
|
|
return 1;
|
|
}
|
|
std::cout << v.value << '\n';
|
|
return 0;
|
|
}
|
|
|
|
int caller2() {
|
|
// it is also possible to capture the value and error in their own variables
|
|
auto [val, err] = foo(argc);
|
|
if (err) {
|
|
return 1;
|
|
}
|
|
std::cout << val << '\n';
|
|
return 0;
|
|
}
|
|
|
|
ox::Error caller3(int &i) {
|
|
return foo(i).moveTo(i);
|
|
}
|
|
|
|
ox::Error caller4(int &i) {
|
|
return foo(i).copyTo(i);
|
|
}
|
|
|
|
int caller5(int i) {
|
|
return foo(i).unwrap(); // unwrap will kill the program if there is an error
|
|
}
|
|
|
|
int caller6(int i) {
|
|
return foo(i).unwrapThrow(); // unwrap will throw if there is an error
|
|
}
|
|
|
|
int caller7(int i) {
|
|
return foo(i).or_value(0); // will return 0 if foo returned an error
|
|
}
|
|
|
|
ox::Result<uint64_t> caller8(int i) {
|
|
return foo(i).to<uint64_t>(); // will convert the result of foo to uint64_t
|
|
}
|
|
```
|
|
|
|
Lastly, there are a few macros available to help in passing ```ox::Error```s
|
|
back up the call stack, ```OX_RETURN_ERROR```, ```OX_THROW_ERROR```, and
|
|
```OX_REQUIRE```.
|
|
|
|
```OX_RETURN_ERROR``` is by far the more helpful of the two.
|
|
```OX_RETURN_ERROR``` will return an ```ox::Error``` if it is not 0 and
|
|
```OX_THROW_ERROR``` will throw an ```ox::Error``` if it is not 0.
|
|
|
|
Since ```ox::Error``` is always nodiscard, you must do something with them.
|
|
In rare cases, you may not have anything you can do with them or you may know
|
|
the code will never fail in that particular instance.
|
|
This should be used sparingly.
|
|
|
|
|
|
```cpp
|
|
void studioCode() {
|
|
auto [val, err] = foo(1);
|
|
OX_THROW_ERROR(err);
|
|
doStuff(val);
|
|
}
|
|
|
|
ox::Error engineCode() noexcept {
|
|
auto [val, err] = foo(1);
|
|
OX_RETURN_ERROR(err);
|
|
doStuff(val);
|
|
return {};
|
|
}
|
|
|
|
void anyCode() {
|
|
auto [val, err] = foo(1);
|
|
std::ignore = err;
|
|
doStuff(val);
|
|
}
|
|
```
|
|
|
|
Both macros will also take the ```ox::Result``` directly:
|
|
|
|
```cpp
|
|
void studioCode() {
|
|
auto valerr = foo(1);
|
|
OX_THROW_ERROR(valerr);
|
|
doStuff(valerr.value);
|
|
}
|
|
|
|
ox::Error engineCode() noexcept {
|
|
auto valerr = foo(1);
|
|
OX_RETURN_ERROR(valerr);
|
|
doStuff(valerr.value);
|
|
return {};
|
|
}
|
|
```
|
|
|
|
Ox also has the ```OX_REQUIRE``` macro, which will initialize a value if there is no error, and return if there is.
|
|
It aims to somewhat emulate the ```?``` operator in Rust and Swift.
|
|
|
|
Rust ```?``` operator:
|
|
```rust
|
|
fn f() -> Result<i32, i32> {
|
|
// do stuff
|
|
}
|
|
|
|
fn f2() -> Result<i32, i32> {
|
|
let i = f()?;
|
|
Ok(i + 4)
|
|
}
|
|
```
|
|
|
|
```OX_REQUIRE```:
|
|
```cpp
|
|
ox::Result<int> f() noexcept {
|
|
// do stuff
|
|
}
|
|
|
|
ox::Result<int> f2() noexcept {
|
|
OX_REQUIRE(i, f()); // const auto [out, OX_CONCAT(oxRequire_err_, __LINE__)] = x; OX_RETURN_ERROR(OX_CONCAT(oxRequire_err_, __LINE__))
|
|
return i + 4;
|
|
}
|
|
```
|
|
```OX_REQUIRE``` is not quite as versatile, but it should still cleanup a lot of otherwise less ideal code.
|
|
|
|
```OX_REQUIRE``` by default creates a const, but there is also an ```OX_REQUIRE_M``` (OX_REQUIRE Mutable)
|
|
variant for creating a non-const value.
|
|
|
|
* ```OX_REQUIRE_M``` - OX_REQUIRE Mutable
|
|
|
|
### Logging and Output
|
|
|
|
Ox provides for logging and debug prints via the ```oxTrace```, ```oxDebug```, and ```oxError``` macros.
|
|
Each of these also provides a format variation.
|
|
|
|
Ox also provide ```oxOut``` and ```oxErr``` for printing to stdout and stderr.
|
|
These are intended for permanent messages and always go to stdout and stderr.
|
|
|
|
Tracing functions do not go to stdout unless the OXTRACE environment variable is set.
|
|
They also print with the channel that they are on, along with file and line.
|
|
|
|
Debug statements go to stdout and go to the logger on the "debug" channel.
|
|
Where trace statements are intended to be written with thoughtfulness,
|
|
debug statements are intended to be quick and temporary insertions.
|
|
Debug statements trigger compilation failures if OX_NODEBUG is enabled when CMake is run,
|
|
as it is on Jenkins builds, so ```oxDebug``` statements should never be checked in.
|
|
This makes ```oxDebug``` preferable to other forms of logging, as temporary prints should
|
|
never be checked in.
|
|
|
|
```oxError``` always prints.
|
|
It includes file and line, and is prefixed with a red "ERROR:".
|
|
It should generally be used conservatively.
|
|
It should be used only when there is an error that is not technically fatal, but
|
|
the user almost certainly wants to know about it.
|
|
|
|
```oxTrace``` and ```oxTracef```:
|
|
```cpp
|
|
void f(int x, int y) { // x = 9, y = 4
|
|
oxTrace("nostalgia.core.sdl.gfx") << "f:" << x << y; // Output: "f: 9 4"
|
|
oxTracef("nostalgia.core.sdl.gfx", "f: {}, {}", x, y); // Output: "f: 9, 4"
|
|
}
|
|
```
|
|
|
|
```oxDebug``` and ```oxDebugf```:
|
|
```cpp
|
|
void f(int x, int y) { // x = 9, y = 4
|
|
oxDebug() << "f:" << x << y; // Output: "f: 9 4"
|
|
oxDebugf("f: {}, {}", x, y); // Output: "f: 9, 4"
|
|
}
|
|
```
|
|
|
|
```oxError``` and ```oxErrorf```:
|
|
```cpp
|
|
void f(int x, int y) { // x = 9, y = 4
|
|
oxError() << "f:" << x << y; // Output: "ERROR: (<file>:<line>): f: 9 4"
|
|
oxErrorf("f: {}, {}", x, y); // Output: "ERROR: (<file>:<line>): f: 9, 4"
|
|
}
|
|
```
|
|
|
|
### Model System
|
|
|
|
Ox has a model system that provides a sort of manual reflection mechanism.
|
|
|
|
Models require a model function for the type that you want to model.
|
|
It is also good to provide a type name and type version number, though that is not required.
|
|
|
|
The model function takes an instance of the type it is modelling and a template
|
|
parameter type.
|
|
The template parameter type must implement the API used in the models, but it
|
|
can do anything with the data provided to it.
|
|
|
|
Here is an example from the Nostalgia/Core package:
|
|
|
|
```cpp
|
|
struct NostalgiaPalette {
|
|
static constexpr auto TypeName = "net.drinkingtea.nostalgia.core.NostalgiaPalette";
|
|
static constexpr auto TypeVersion = 1;
|
|
ox::Vector<Color16> colors;
|
|
};
|
|
|
|
struct NostalgiaGraphic {
|
|
static constexpr auto TypeName = "net.drinkingtea.nostalgia.core.NostalgiaGraphic";
|
|
static constexpr auto TypeVersion = 1;
|
|
int8_t bpp = 0;
|
|
// rows and columns are really only used by TileSheetEditor
|
|
int rows = 1;
|
|
int columns = 1;
|
|
ox::FileAddress defaultPalette;
|
|
NostalgiaPalette pal;
|
|
ox::Vector<uint8_t> pixels;
|
|
};
|
|
|
|
template<typename T>
|
|
constexpr ox::Error model(T *h, ox::CommonPtrWith<NostalgiaPalette> auto *pal) noexcept {
|
|
h->template setTypeInfo<NostalgiaPalette>();
|
|
// it is also possible to provide the type name and type version as function arguments
|
|
//h->setTypeInfo("net.drinkingtea.nostalgia.core.NostalgiaPalette", 1);
|
|
OX_RETURN_ERROR(h->field("colors", &pal->colors));
|
|
return {};
|
|
}
|
|
|
|
template<typename T>
|
|
constexpr ox::Error model(T *h, ox::CommonPtrWith<NostalgiaGraphic> auto *ng) noexcept {
|
|
h->template setTypeInfo<NostalgiaGraphic>();
|
|
OX_RETURN_ERROR(h->field("bpp", &ng->bpp));
|
|
OX_RETURN_ERROR(h->field("rows", &ng->rows));
|
|
OX_RETURN_ERROR(h->field("columns", &ng->columns));
|
|
OX_RETURN_ERROR(h->field("defaultPalette", &ng->defaultPalette));
|
|
OX_RETURN_ERROR(h->field("pal", &ng->pal));
|
|
OX_RETURN_ERROR(h->field("pixels", &ng->pixels));
|
|
return {};
|
|
}
|
|
```
|
|
|
|
The model system also provides for unions:
|
|
|
|
```cpp
|
|
|
|
#include <ox/model/types.hpp>
|
|
|
|
class FileAddress {
|
|
|
|
template<typename T>
|
|
friend constexpr Error model(T*, ox::CommonPtrWith<FileAddress> auto*) noexcept;
|
|
|
|
public:
|
|
static constexpr auto TypeName = "net.drinkingtea.ox.FileAddress";
|
|
|
|
union Data {
|
|
static constexpr auto TypeName = "net.drinkingtea.ox.FileAddress.Data";
|
|
char *path;
|
|
const char *constPath;
|
|
uint64_t inode;
|
|
};
|
|
|
|
protected:
|
|
FileAddressType m_type = FileAddressType::None;
|
|
Data m_data;
|
|
|
|
};
|
|
|
|
template<typename T>
|
|
constexpr Error model(T *h, ox::CommonPtrWith<FileAddress::Data> auto *obj) noexcept {
|
|
h->template setTypeInfo<FileAddress::Data>();
|
|
OX_RETURN_ERROR(h->fieldCString("path", &obj->path));
|
|
OX_RETURN_ERROR(h->fieldCString("constPath", &obj->path));
|
|
OX_RETURN_ERROR(h->field("inode", &obj->inode));
|
|
return {};
|
|
}
|
|
|
|
template<typename T>
|
|
constexpr Error model(T *io, ox::CommonPtrWith<FileAddress> auto *fa) noexcept {
|
|
io->template setTypeInfo<FileAddress>();
|
|
// cannot read from object in Reflect operation
|
|
if constexpr(ox_strcmp(T::opType(), OpType::Reflect) == 0) {
|
|
int8_t type = 0;
|
|
OX_RETURN_ERROR(io->field("type", &type));
|
|
OX_RETURN_ERROR(io->field("data", UnionView(&fa->m_data, 0)));
|
|
} else {
|
|
auto type = static_cast<int8_t>(fa->m_type);
|
|
OX_RETURN_ERROR(io->field("type", &type));
|
|
fa->m_type = static_cast<FileAddressType>(type);
|
|
OX_RETURN_ERROR(io->field("data", UnionView(&fa->m_data, static_cast<int>(fa->m_type))));
|
|
}
|
|
return {};
|
|
}
|
|
|
|
```
|
|
|
|
There are also macros in ```<ox/model/def.hpp>``` for simplifying the declaration of models:
|
|
|
|
```cpp
|
|
OX_MODEL_BEGIN(NostalgiaGraphic)
|
|
OX_MODEL_FIELD(bpp)
|
|
OX_MODEL_FIELD(rows)
|
|
OX_MODEL_FIELD(columns)
|
|
OX_MODEL_FIELD(defaultPalette)
|
|
OX_MODEL_FIELD(pal)
|
|
OX_MODEL_FIELD(pixels)
|
|
oxModelEnd()
|
|
```
|
|
|
|
### Serialization
|
|
|
|
Using the model system, Ox provides for serialization.
|
|
Ox has MetalClaw and OrganicClaw as its serialization format options.
|
|
MetalClaw is a custom binary format designed for minimal size.
|
|
OrganicClaw is a wrapper around JsonCpp, chosen because it technically
|
|
implements a superset of JSON.
|
|
OrganicClaw requires support for 64 bit integers, whereas normal JSON
|
|
technically does not.
|
|
|
|
These formats do not currently support floats.
|
|
|
|
There is also a wrapper format called Claw that provides a header at the
|
|
beginning of the file and can dynamically switch between the two depending on
|
|
what the header says is present.
|
|
The Claw header also includes information about the type and type version of
|
|
the data.
|
|
|
|
Claw header: ```M1;net.drinkingtea.nostalgia.core.NostalgiaPalette;1;```
|
|
|
|
That reads:
|
|
|
|
* Format is Metal Claw, version 1
|
|
* Type ID is net.drinkingtea.nostalgia.core.NostalgiaPalette
|
|
* Type version is 1
|
|
|
|
#### Metal Claw Example
|
|
|
|
##### Read
|
|
|
|
```cpp
|
|
#include <ox/mc/read.hpp>
|
|
|
|
ox::Result<NostalgiaPalette> loadPalette1(ox::BufferView const&buff) noexcept {
|
|
return ox::readMC<NostalgiaPalette>(buff);
|
|
}
|
|
|
|
ox::Result<NostalgiaPalette> loadPalette2(ox::BufferView const&buff) noexcept {
|
|
NostalgiaPalette pal;
|
|
OX_RETURN_ERROR(ox::readMC(buff, pal));
|
|
return pal;
|
|
}
|
|
```
|
|
|
|
##### Write
|
|
|
|
```cpp
|
|
#include <ox/mc/write.hpp>
|
|
|
|
ox::Result<ox::Buffer> writeSpritePalette1(NostalgiaPalette const&pal) noexcept {
|
|
ox::Buffer buffer(ox::units::MB);
|
|
std::size_t sz = 0;
|
|
OX_RETURN_ERROR(ox::writeMC(buffer.data(), buffer.size(), pal, &sz));
|
|
buffer.resize(sz);
|
|
return buffer;
|
|
}
|
|
|
|
ox::Result<ox::Buffer> writeSpritePalette2(NostalgiaPalette const&pal) noexcept {
|
|
return ox::writeMC(pal);
|
|
}
|
|
```
|
|
|
|
#### Organic Claw Example
|
|
|
|
##### Read
|
|
|
|
```cpp
|
|
#include <ox/oc/read.hpp>
|
|
|
|
ox::Result<NostalgiaPalette> loadPalette1(ox::BufferView const&buff) noexcept {
|
|
return ox::readOC<NostalgiaPalette>(buff);
|
|
}
|
|
|
|
ox::Result<NostalgiaPalette> loadPalette2(ox::BufferView const&buff) noexcept {
|
|
NostalgiaPalette pal;
|
|
OX_RETURN_ERROR(ox::readOC(buff, &pal));
|
|
return pal;
|
|
}
|
|
```
|
|
|
|
##### Write
|
|
|
|
```cpp
|
|
#include <ox/oc/write.hpp>
|
|
|
|
ox::Result<ox::Buffer> writeSpritePalette1(NostalgiaPalette const&pal) noexcept {
|
|
ox::Buffer buffer(ox::units::MB);
|
|
OX_RETURN_ERROR(ox::writeOC(buffer.data(), buffer.size(), pal));
|
|
return buffer;
|
|
}
|
|
|
|
ox::Result<ox::Buffer> writeSpritePalette2(NostalgiaPalette const&pal) noexcept {
|
|
return ox::writeOC(pal);
|
|
}
|
|
```
|
|
|
|
#### Claw Example
|
|
|
|
##### Read
|
|
|
|
```cpp
|
|
#include <ox/claw/read.hpp>
|
|
|
|
ox::Result<NostalgiaPalette> loadPalette1(ox::BufferView const&buff) noexcept {
|
|
return ox::readClaw<NostalgiaPalette>(buff);
|
|
}
|
|
|
|
ox::Result<NostalgiaPalette> loadPalette2(ox::BufferView const&buff) noexcept {
|
|
NostalgiaPalette pal;
|
|
OX_RETURN_ERROR(ox::readClaw(buff, pal));
|
|
return pal;
|
|
}
|
|
```
|
|
|
|
##### Write
|
|
|
|
```cpp
|
|
#include <ox/claw/write.hpp>
|
|
|
|
ox::Result<ox::Buffer> writeSpritePalette(NostalgiaPalette const&pal) noexcept {
|
|
return ox::writeClaw(pal);
|
|
}
|
|
```
|