openNGVFS/docs/ngvfs_docs.typ

#import "../docs_common/template/template.typ" : ZRYGenericDocs
#import "@preview/tablex:0.0.8": tablex, colspanx, rowspanx
#import "@preview/oxifmt:0.2.0": strfmt

#let pageCounting = locate(loc=>counter(page).final(loc).at(0))
#let title = "openNGVFS 文档"
#let version = (
	major: 1,
	minor: 1,
	patch: 0,
)
#let semVerStr = strfmt("{}.{}.{}", version.major, version.minor, version.patch)

#show: body => ZRYGenericDocs(
    title: title,
    subTitle: "",
    titleDesc: "",
    docVer: "API Ver. " + semVerStr,
    headerSettings: (
        enable: true,
        ascent: 20%,
        content: locate(loc => {
          let elems = query(selector(heading).before(loc), loc)
          if counter(page).at(loc).first() > 1 [
            #text(
              weight: "bold",
              size: 0.9em,
            )[
              #title
            ]
            #h(1fr)
            #text(
              weight: "thin",
              size: 0.7em,
            )[
              #counter(page).display() / #pageCounting
            ]
            #line(length: 100%)
          ]
        }),
    ),
    footerSettings: (
        enable: true,
        descent: 30%,
        content: locate(loc => {
          if counter(page).at(loc).first() > 1 [
            #line(length: 100%)
            #text(
              weight: "thin",
              size: 0.6em,
            )[
              公开文档
            ]
          ]
        }),
    ),
    body
)

= 项目说明

该项目基于商业项目ProjectNagae下属的NagaeVFS V1.1.0，为NagaeVFS的开源版本。该版本使用MIT License开源。注意，NagaeVFS后续版本将不再与openNGVFS兼容。

= 版本说明

当前版本从NagaeVFS V1.1.0衍生，经过一定程度的测试，但使用前请自行进行必要的功能测试。

当前版本提供以下功能。

== VFS

一个可挂载的虚拟文件系统。其主机接口兼容afero.Fs。

== INIT WASM

用于初始化文件系统挂载的WASM虚拟机。

该虚拟机提供以下接口：
+ 在主机上创建和释放afero.Fs对象的接口。
+ 挂载主机上被创建的afero.Fs对象的接口。
+ 在主机VFS上创建目录的接口。
+ 读取配置文件中ExKV键值对内容的接口。

=== 可创建的afs对象

==== 来自afero.Fs的类型

当前版本可创建的afero.Fs对象，由afero包本身提供的有：

- afero.OsFs
- afero.MemMapFs
- afero.BasePathFs
- afero.RegexpFs
- afero.ReadOnlyFs
- afero.CopyOnWriteFs
- afero.CacheOnReadFs

其中经过简单测试并通过的有：

- afero.OsFs
- afero.MemMapFs
- afero.BasePathFs
- afero.ReadOnlyFs

其中经过测试有问题的：

- afero.RegexpFs
   - Readdir功能在遇到无法匹配的文件时产生error
     
     该问题来自afero.RegexpFs本身，故不提供其修正。

     谨慎考虑使用RegexpFs。

==== 来自第三方的

- `"github.com/bep/overlayfs" overlayfs.OverlayFs`
    
    经过测试，但有如下问题：
      - 不支持在子目录下创建文件，会产生错误
        
        `The system cannot find the path specified.`

= INIT WASI接口

== WASM导出函数
#{
  let data = yaml("init_wasi_export.yaml")
  for funcPair in data {
    {
      let funcName = funcPair.at(0)
      [==== 函数 #raw(funcName)]
      let funcPart = funcPair.at(1)
      let funcParams = funcPart.at("params", default: none)
      let funcResults = funcPart.at("results", default: none)
      let prototypeParams = if funcParams != none and funcParams.len() > 0 {
        let prototypeParamsList = ()
        for iParam in funcParams {
          prototypeParamsList.push(iParam.name + ": " + iParam.type)
        }
        prototypeParamsList.join(",")
      }else{""}
      let prototypeCode = "fn " + funcName + "(" + prototypeParams + ")"
      let prototypeResult = if funcResults != none and funcResults.len() > 0 {
        let prototypeResultList = ()
        for iResult in funcResults {
          prototypeResultList.push(iResult.name + ": " + iResult.type)
        }
        " -> (" + prototypeResultList.join(",") + ")"
      }else{""}
      prototypeCode = prototypeCode + prototypeResult + ";"
      let prototype = raw(prototypeCode, lang:"rust")
      let tableContent = (
        [*名称*], colspanx(4)[#funcPair.at(0)],
        [*说明*], colspanx(4)[#funcPart.desc],
        [*原型*], colspanx(4)[#prototype],
      )
      if funcParams != none and funcParams.len() > 0 {
        let lenParams = funcParams.len()
        tableContent.push(rowspanx(lenParams+1)[*参数*])
        tableContent.push([*名称*])
        tableContent.push([*WASM类型*])
        tableContent.push([*语义类型*])
        tableContent.push([*说明*])
        for param in funcParams {
          let paramEnum = param.at("enum", default: none)
          tableContent.push(param.name)
          tableContent.push(param.type)
          tableContent.push(if param.xtyp != none {param.xtyp} else {param.type})
          tableContent.push(
            if paramEnum != none [
              #param.desc
              #let paramEnumTable = ()
              #for peti in paramEnum {
                paramEnumTable.push(peti.at(0))
                paramEnumTable.push(peti.at(1))
              }
              #tablex(
                columns: 2,
                [*值*], [*说明*],
                ..paramEnumTable
              )
            ]else[#param.desc]
          )
        }
      }
      if funcResults != none and funcResults.len() > 0 {
        let lenResults = funcResults.len()
        tableContent.push(rowspanx(lenResults+1)[*返回值*])
        tableContent.push([*名称*])
        tableContent.push([*WASM类型*])
        tableContent.push([*语义类型*])
        tableContent.push([*说明*])
        for param in funcResults {
          let paramEnum = param.at("enum", default: none)
          let paramXtyp = param.at("xtyp", default: none)
          tableContent.push(param.name)
          tableContent.push(param.type)
          tableContent.push(if paramXtyp != none {paramXtyp} else {param.type})
          tableContent.push(
            if paramEnum != none [
              #param.desc
              #let paramEnumTable = ()
              #for peti in paramEnum {
                paramEnumTable.push(peti.at(0))
                paramEnumTable.push(peti.at(1))
              }
              #tablex(
                columns: 2,
                [*值*], [*说明*],
                ..paramEnumTable
              )
            ]else[#param.desc]
          )
        }
      }
      tablex(
        columns: 5,
        ..tableContent
      )
    }
  }
} 

== 主机导出模块

#{
  let data = yaml("init_wasi_import.yaml")
  for modPair in data {
    [=== 模块 #raw(modPair.at(0))]
    for funcPair in modPair.at(1) {
      {
        let funcName = funcPair.at(0)
        [==== 函数 #raw(funcName)]
        let funcPart = funcPair.at(1)
        let funcParams = funcPart.at("params", default: none)
        let funcResults = funcPart.at("results", default: none)
        let prototypeParams = if funcParams != none and funcParams.len() > 0 {
          let prototypeParamsList = ()
          for iParam in funcParams {
            prototypeParamsList.push(iParam.name + ": " + iParam.type)
          }
          prototypeParamsList.join(",")
        }else{""}
        let prototypeCode = "fn " + funcName + "(" + prototypeParams + ")"
        let prototypeResult = if funcResults != none and funcResults.len() > 0 {
          let prototypeResultList = ()
          for iResult in funcResults {
            prototypeResultList.push(iResult.name + ": " + iResult.type)
          }
          " -> (" + prototypeResultList.join(",") + ")"
        }else{""}
        prototypeCode = prototypeCode + prototypeResult + ";"
        let prototype = raw(prototypeCode, lang:"rust")
        let tableContent = (
          [*名称*], colspanx(4)[#funcPair.at(0)],
          [*说明*], colspanx(4)[#funcPart.desc],
          [*原型*], colspanx(4)[#prototype],
        )
        if funcParams != none and funcParams.len() > 0 {
          let lenParams = funcParams.len()
          tableContent.push(rowspanx(lenParams+1)[*参数*])
          tableContent.push([*名称*])
          tableContent.push([*WASM类型*])
          tableContent.push([*语义类型*])
          tableContent.push([*说明*])
          for param in funcParams {
            let paramEnum = param.at("enum", default: none)
            let paramXtyp = param.at("xtyp", default: none)
            tableContent.push(param.name)
            tableContent.push(param.type)
            tableContent.push(if paramXtyp != none {paramXtyp} else {param.type})
            tableContent.push(
              if paramEnum != none [
                #param.desc
                #let paramEnumTable = ()
                #for peti in paramEnum {
                  paramEnumTable.push(peti.at(0))
                  paramEnumTable.push(peti.at(1))
                }
                #tablex(
                  columns: 2,
                  [*值*], [*说明*],
                  ..paramEnumTable
                )
              ]else[#param.desc]
            )
          }
        }
        if funcResults != none and funcResults.len() > 0 {
          let lenResults = funcResults.len()
          tableContent.push(rowspanx(lenResults+1)[*返回值*])
          tableContent.push([*名称*])
          tableContent.push([*WASM类型*])
          tableContent.push([*语义类型*])
          tableContent.push([*说明*])
          for param in funcResults {
            let paramEnum = param.at("enum", default: none)
            tableContent.push(param.name)
            tableContent.push(param.type)
            tableContent.push(if param.xtyp != none {param.xtyp} else {param.type})
            tableContent.push(
              if paramEnum != none [
                #param.desc
                #let paramEnumTable = ()
                #for peti in paramEnum {
                  paramEnumTable.push(peti.at(0))
                  paramEnumTable.push(peti.at(1))
                }
                #tablex(
                  columns: 2,
                  [*值*], [*说明*],
                  ..paramEnumTable
                )
              ]else[#param.desc]
            )
          }
        }
        tablex(
          columns: 5,
          ..tableContent
        )
      }
    }
  }
} 

== WASM侧Rust Crate

提供有用于WASM侧的接口包装Rust Crate。

目前本文档内暂不提供该Crate的文档。

该包的交互式文档可使用rustdoc生成：

```bash
cd init-wasm
just doc_html
```

生成的文档在`init-wasm/ngvfs_init_wasm_lib/target/doc/ngvfs_init_wasm_lib`

若安装有`SimpleHttpTestServer`，可继续使用如下命令：

```bash
# 端口号可换成其他值
just serv_doc "localhost:8088"
```

然后使用浏览器打开 #link("http://localhsot:8088/")。