formats.libconfig: init

Co-authored-by: ckie <25263210+ckiee@users.noreply.github.com>
Signed-off-by: h7x4 <h7x4@nani.wtf>

pkgs/pkgs-lib/formats.nix

@@ -34,6 +34,8 @@ rec {
   inherit (import ./formats/java-properties/default.nix { inherit lib pkgs; })
     javaProperties;
 
+  libconfig = (import ./formats/libconfig/default.nix { inherit lib pkgs; }).format;
+
   json = {}: {
 
     type = with lib.types; let

pkgs/pkgs-lib/formats/libconfig/default.nix

@@ -0,0 +1,121 @@
+{ lib
+, pkgs
+}:
+let
+  inherit (pkgs) buildPackages callPackage;
+  # Implementation notes:
+  #   Libconfig spec: https://hyperrealm.github.io/libconfig/libconfig_manual.html
+  #
+  #   Since libconfig does not allow setting names to start with an underscore,
+  #   this is used as a prefix for both special types and include directives.
+  #
+  #   The difference between 32bit and 64bit values became optional in libconfig
+  #   1.5, so we assume 64bit values for all numbers.
+
+  libconfig-generator = buildPackages.rustPlatform.buildRustPackage {
+    name = "libconfig-generator";
+    version = "0.1.0";
+    src = ./src;
+
+    passthru.updateScript = ./update.sh;
+
+    cargoLock.lockFile = ./src/Cargo.lock;
+  };
+
+  libconfig-validator = buildPackages.runCommandCC "libconfig-validator"
+    {
+      buildInputs = with buildPackages; [ libconfig ];
+    }
+    ''
+      mkdir -p "$out/bin"
+      $CC -lconfig -x c - -o "$out/bin/libconfig-validator" ${./validator.c}
+    '';
+in
+{
+  format = { generator ? libconfig-generator, validator ? libconfig-validator }: {
+    inherit generator;
+
+    type = with lib.types;
+      let
+        valueType = (oneOf [
+          bool
+          int
+          float
+          str
+          path
+          (attrsOf valueType)
+          (listOf valueType)
+        ]) // {
+          description = "libconfig value";
+        };
+      in
+      attrsOf valueType;
+
+    lib = {
+      mkHex = value: {
+        _type = "hex";
+        inherit value;
+      };
+      mkOctal = value: {
+        _type = "octal";
+        inherit value;
+      };
+      mkFloat = value: {
+        _type = "float";
+        inherit value;
+      };
+      mkArray = value: {
+        _type = "array";
+        inherit value;
+      };
+      mkList = value: {
+        _type = "list";
+        inherit value;
+      };
+    };
+
+    generate = name: value:
+      callPackage
+        ({
+          stdenvNoCC
+        , libconfig-generator
+        , libconfig-validator
+        , writeText
+        }: stdenvNoCC.mkDerivation rec {
+          inherit name;
+
+          dontUnpack = true;
+
+          json = builtins.toJSON value;
+          passAsFile = [ "json" ];
+
+          strictDeps = true;
+          nativeBuildInputs = [ libconfig-generator ];
+          buildPhase = ''
+            runHook preBuild
+            libconfig-generator < $jsonPath > output.cfg
+            runHook postBuild
+          '';
+
+          doCheck = true;
+          nativeCheckInputs = [ libconfig-validator ];
+          checkPhase = ''
+            runHook preCheck
+            libconfig-validator output.cfg
+            runHook postCheck
+          '';
+
+          installPhase = ''
+            runHook preInstall
+            mv output.cfg $out
+            runHook postInstall
+          '';
+
+          passthru.json = writeText "${name}.json" json;
+        })
+        {
+          libconfig-generator = generator;
+          libconfig-validator = validator;
+        };
+  };
+}

pkgs/pkgs-lib/formats/libconfig/src/Cargo.lock

@@ -0,0 +1,40 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "itoa"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af150ab688ff2122fcef229be89cb50dd66af9e01a4ff320cc137eecc9bacc38"
+
+[[package]]
+name = "libconfig-generator"
+version = "0.1.0"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ad4cc8da4ef723ed60bced201181d83791ad433213d8c24efffda1eec85d741"
+
+[[package]]
+name = "serde"
+version = "1.0.183"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32ac8da02677876d532745a130fc9d8e6edfa81a269b107c5b00829b91d8eb3c"
+
+[[package]]
+name = "serde_json"
+version = "1.0.104"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "076066c5f1078eac5b722a31827a8832fe108bed65dfa75e233c89f8206e976c"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]

pkgs/pkgs-lib/formats/libconfig/src/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "libconfig-generator"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+serde = "1.0.178"
+serde_json = "1.0.104"

pkgs/pkgs-lib/formats/libconfig/src/src/main.rs

@@ -0,0 +1,271 @@
+use serde_json::Value;
+use std::mem::discriminant;
+
+#[derive(Debug)]
+enum LibConfigIntNumber {
+    Oct(i64),
+    Hex(i64),
+    Int(i64),
+}
+
+#[derive(Debug)]
+enum LibConfigValue {
+    Bool(bool),
+    Int(LibConfigIntNumber),
+    Float(f64),
+    String(String),
+    Array(Vec<LibConfigValue>),
+    List(Vec<LibConfigValue>),
+    Group(Vec<String>, Vec<(String, LibConfigValue)>),
+}
+
+fn validate_setting_name(key: &str) -> bool {
+    let first_char = key.chars().next().expect("Empty setting name");
+    (first_char.is_alphabetic() || first_char == '*')
+        && key[1..]
+            .chars()
+            .all(|c| c.is_alphanumeric() || c == '_' || c == '*')
+}
+
+const SPECIAL_TYPES: [&str; 5] = ["octal", "hex", "float", "list", "array"];
+
+fn object_is_special_type(o: &serde_json::Map<String, Value>) -> Option<&str> {
+    o.get("_type").and_then(|x| x.as_str()).and_then(|x| {
+        if SPECIAL_TYPES.contains(&x) {
+            Some(x)
+        } else {
+            None
+        }
+    })
+}
+
+fn vec_is_array(v: &Vec<LibConfigValue>) -> bool {
+    if v.is_empty() {
+        return true;
+    }
+
+    let first_item = v.first().unwrap();
+
+    if match first_item {
+        LibConfigValue::Array(_) => true,
+        LibConfigValue::List(_) => true,
+        LibConfigValue::Group(_, _) => true,
+        _ => false,
+    } {
+        return false;
+    };
+
+    v[1..]
+        .iter()
+        .all(|item| discriminant(first_item) == discriminant(item))
+}
+
+fn json_to_libconfig(v: &Value) -> LibConfigValue {
+    match v {
+        Value::Null => panic!("Null value not allowed in libconfig"),
+        Value::Bool(b) => LibConfigValue::Bool(b.clone()),
+        Value::Number(n) => {
+            if n.is_i64() {
+                LibConfigValue::Int(LibConfigIntNumber::Int(n.as_i64().unwrap()))
+            } else if n.is_f64() {
+                LibConfigValue::Float(n.as_f64().unwrap())
+            } else {
+                panic!("{} is not i64 or f64, cannot be represented as number in libconfig", n);
+            }
+        }
+        Value::String(s) => LibConfigValue::String(s.to_string()),
+        Value::Array(a) => {
+            let items = a
+                .iter()
+                .map(|item| json_to_libconfig(item))
+                .collect::<Vec<LibConfigValue>>();
+            LibConfigValue::List(items)
+        }
+        Value::Object(o) => {
+            if let Some(_type) = object_is_special_type(o) {
+                let value = o
+                    .get("value")
+                    .expect(format!("Missing value for special type: {}", &_type).as_str());
+
+                return match _type {
+                    "octal" => {
+                        let str_value = value
+                            .as_str()
+                            .expect(
+                                format!("Value is not a string for special type: {}", &_type)
+                                    .as_str(),
+                            )
+                            .to_owned();
+
+                        LibConfigValue::Int(LibConfigIntNumber::Oct(
+                            i64::from_str_radix(&str_value, 8)
+                                .expect(format!("Invalid octal value: {}", value).as_str()),
+                        ))
+                    }
+                    "hex" => {
+                        let str_value = value
+                            .as_str()
+                            .expect(
+                                format!("Value is not a string for special type: {}", &_type)
+                                    .as_str(),
+                            )
+                            .to_owned();
+
+                        LibConfigValue::Int(LibConfigIntNumber::Hex(
+                            i64::from_str_radix(&str_value[2..], 16)
+                                .expect(format!("Invalid hex value: {}", value).as_str()),
+                        ))
+                    }
+                    "float" => {
+                        let str_value = value
+                            .as_str()
+                            .expect(
+                                format!("Value is not a string for special type: {}", &_type)
+                                    .as_str(),
+                            )
+                            .to_owned();
+
+                        LibConfigValue::Float(
+                            str_value
+                                .parse::<f64>()
+                                .expect(format!("Invalid float value: {}", value).as_str()),
+                        )
+                    }
+                    "list" => {
+                        let items = value
+                            .as_array()
+                            .expect(
+                                format!("Value is not an array for special type: {}", &_type)
+                                    .as_str(),
+                            )
+                            .to_owned()
+                            .iter()
+                            .map(|item| json_to_libconfig(item))
+                            .collect::<Vec<LibConfigValue>>();
+
+                        LibConfigValue::List(items)
+                    }
+                    "array" => {
+                        let items = value
+                            .as_array()
+                            .expect(
+                                format!("Value is not an array for special type: {}", &_type)
+                                    .as_str(),
+                            )
+                            .to_owned()
+                            .iter()
+                            .map(|item| json_to_libconfig(item))
+                            .collect::<Vec<LibConfigValue>>();
+
+                        if !vec_is_array(&items) {
+                            panic!(
+                                "This can not be an array because of its contents: {:#?}",
+                                items
+                            );
+                        }
+
+                        LibConfigValue::Array(items)
+                    }
+                    _ => panic!("Invalid type: {}", _type),
+                };
+            }
+
+            let mut items = o
+                .iter()
+                .filter(|(key, _)| key.as_str() != "_includes")
+                .map(|(key, value)| (key.clone(), json_to_libconfig(value)))
+                .collect::<Vec<(String, LibConfigValue)>>();
+            items.sort_by(|(a,_),(b,_)| a.partial_cmp(b).unwrap());
+
+            let includes = o
+                .get("_includes")
+                .map(|x| {
+                    x.as_array()
+                        .expect("_includes is not an array")
+                        .iter()
+                        .map(|x| {
+                            x.as_str()
+                                .expect("_includes item is not a string")
+                                .to_owned()
+                        })
+                        .collect::<Vec<String>>()
+                })
+                .unwrap_or(vec![]);
+
+            for (key,_) in items.iter() {
+                if !validate_setting_name(key) {
+                    panic!("Invalid setting name: {}", key);
+                }
+            }
+            LibConfigValue::Group(includes, items)
+        }
+    }
+}
+
+impl ToString for LibConfigValue {
+    fn to_string(&self) -> String {
+        match self {
+            LibConfigValue::Bool(b) => b.to_string(),
+            LibConfigValue::Int(i) => match i {
+                LibConfigIntNumber::Oct(n) => format!("0{:o}", n),
+                LibConfigIntNumber::Hex(n) => format!("0x{:x}", n),
+                LibConfigIntNumber::Int(n) => n.to_string(),
+            },
+            LibConfigValue::Float(n) => format!("{:?}", n),
+            LibConfigValue::String(s) => {
+                format!("\"{}\"", s.replace("\\", "\\\\").replace("\"", "\\\""))
+            }
+            LibConfigValue::Array(a) => {
+                let items = a
+                    .iter()
+                    .map(|item| item.to_string())
+                    .collect::<Vec<String>>()
+                    .join(", ");
+                format!("[{}]", items)
+            }
+            LibConfigValue::List(a) => {
+                let items = a
+                    .iter()
+                    .map(|item| item.to_string())
+                    .collect::<Vec<String>>()
+                    .join(", ");
+                format!("({})", items)
+            }
+            LibConfigValue::Group(i, o) => {
+                let includes = i
+                    .iter()
+                    .map(|x| x.replace("\\", "\\\\").replace("\"", "\\\""))
+                    .map(|x| format!("@include \"{}\"", x))
+                    .collect::<Vec<String>>()
+                    .join("\n");
+                let items = o
+                    .iter()
+                    .map(|(key, value)| format!("{}={};", key, value.to_string()))
+                    .collect::<Vec<String>>()
+                    .join("");
+                if includes.is_empty() {
+                    format!("{{{}}}", items)
+                } else {
+                    format!("{{\n{}\n{}}}", includes, items)
+                }
+            }
+        }
+    }
+}
+
+fn main() {
+    let stdin = std::io::stdin().lock();
+    let json = serde_json::Deserializer::from_reader(stdin)
+        .into_iter::<Value>()
+        .next()
+        .expect("Could not read content from stdin")
+        .expect("Could not parse JSON from stdin");
+
+    for (key, value) in json
+        .as_object()
+        .expect("Top level of JSON file is not an object")
+    {
+        print!("{}={};", key, json_to_libconfig(value).to_string());
+    }
+    print!("\n\n");
+}

pkgs/pkgs-lib/formats/libconfig/update.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -p cargo -i bash
+cd "$(dirname "$0")"
+cargo update

pkgs/pkgs-lib/formats/libconfig/validator.c

@@ -0,0 +1,21 @@
+//    Copyright (C) 2005-2023  Mark A Lindner, ckie
+//    SPDX-License-Identifier: LGPL-2.1-or-later
+#include <stdio.h>
+#include <libconfig.h>
+int main(int argc, char **argv)
+{
+  config_t cfg;
+  config_init(&cfg);
+  if (argc != 2)
+  {
+    fprintf(stderr, "USAGE: validator <path-to-validate>");
+  }
+  if(! config_read_file(&cfg, argv[1]))
+  {
+    fprintf(stderr, "[libconfig] %s:%d - %s\n", config_error_file(&cfg),
+            config_error_line(&cfg), config_error_text(&cfg));
+    config_destroy(&cfg);
+    return 1;
+  }
+  printf("[libconfig] validation ok\n");
+}