major rewrite #2, dependency functionality

src/content_generation/compile_commands.rs

@@ -1,14 +1,18 @@
-use std::path::Path;
+use std::{
+    fs::OpenOptions,
+    io::{BufWriter, Write},
+    path::Path,
+};
 
-use crate::parsed_config_processing::*;
+use crate::parse_deser::*;
 
 use super::*;
 
-pub fn gen_compile_commands(
+pub fn create_compile_commands_content(
     name: &str,
     target: &Target,
-    config: &ConfigTable,
+    config: &Config,
-) -> Result<String, ContentGenerationError> {
+) -> Result<String> {
     let mut ret = "[\n".to_string();
 
     let compiler_flags = target.compiler_flags.join(" ");
@@ -18,7 +22,8 @@ pub fn gen_compile_commands(
     let pwd = pwd.to_str().unwrap();
 
     if target.sources.len() == 0 {
-        return Err(ContentGenerationError {
+        return Err(Error {
+            kind: ErrorKind::NoSources,
             message: format!(
                 "compile_commands_target is set to `{0}`, however `{0}` has no sources.",
                 name
@@ -48,3 +53,15 @@ pub fn gen_compile_commands(
 
     Ok(ret)
 }
+
+pub fn write_compile_commands(filename: &str, content: &[u8]) -> std::io::Result<()> {
+    let file = OpenOptions::new()
+        .write(true)
+        .truncate(true)
+        .create(true)
+        .open(filename)?;
+
+    let mut writer = BufWriter::new(file);
+    writer.write(content)?;
+    Ok(())
+}

src/content_generation/error.rs

@@ -1,11 +1,18 @@
 use std::fmt::Display;
 
-pub struct ContentGenerationError {
+pub enum ErrorKind {
+    NoSources,
+}
+
+pub struct Error {
+    pub kind: ErrorKind,
     pub message: String,
 }
 
-impl Display for ContentGenerationError {
+impl Display for Error {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "content generation error: {}", self.message)
     }
 }
+
+pub type Result<T> = std::result::Result<T, Error>;

src/content_generation/mod.rs

@@ -1,7 +1,7 @@
 pub mod compile_commands;
-pub mod content_generation_error;
+pub mod error;
 pub mod ninja_file;
 
 pub use compile_commands::*;
-pub use content_generation_error::*;
+pub use error::*;
 pub use ninja_file::*;

src/content_generation/ninja_file.rs

@@ -1,8 +1,12 @@
+use std::fs::OpenOptions;
+use std::io::BufWriter;
+use std::io::Write;
+
 use super::*;
-use crate::parsed_config_processing::*;
+use crate::parse_deser::*;
 use crate::Args;
 
-pub fn gen_ninja_header(config: &ConfigTable, cmdline_args: &Args) -> String {
+pub fn gen_ninja_header(config: &Config, cmdline_args: &Args) -> Result<String> {
     let mut ret = "".to_string();
     ret.push_str(&format!(
         "## Generated by ngen
@@ -45,12 +49,13 @@ build {0}: regen_ninjafile {1} || $builddir/compile_commands.json
             cmdline_args.output_file, cmdline_args.config_file
         ));
     }
-    ret
+    Ok(ret)
 }
 
-pub fn gen_ninja_target(name: &str, target: &Target) -> Result<String, ContentGenerationError> {
+pub fn gen_ninja_target(name: &str, target: &Target) -> Result<String> {
     if target.sources.len() == 0 {
-        return Err(ContentGenerationError {
+        return Err(Error {
+            kind: ErrorKind::NoSources,
             message: format!("target `{}` has no sources", name),
         });
     }
@@ -97,9 +102,10 @@ build $builddir/{0}/dep: mkdir
         name, target.outfile
     ));
     ret.push_str(&object_list.join(" "));
+    let deps = &target.opts.depend_on.join(" ");
     ret.push_str(&format!(
-        " || $builddir/{0}/obj $builddir/{0}/dep\nbuild {0}: phony $builddir/{0}/{1}\n",
+        " | {2} || $builddir/{0}/obj $builddir/{0}/dep\nbuild {0}: phony $builddir/{0}/{1}\n",
-        name, target.outfile
+        name, target.outfile, deps
     ));
     if target.opts.default {
         ret.push_str(&format!("\ndefault {}\n", name));
@@ -107,3 +113,39 @@ build $builddir/{0}/dep: mkdir
     ret.push_str(&format!("# END TARGET {}\n", name));
     Ok(ret)
 }
+
+pub fn create_ninja_file_content(
+    target_list: &TargetList,
+    config: &Config,
+    args: &Args,
+) -> Result<String> {
+    let mut ret = String::new();
+    ret.push_str(&gen_ninja_header(&config, &args)?);
+    for (name, target) in &target_list.0 {
+        let content = gen_ninja_target(name, target);
+        match content {
+            Ok(v) => ret.push_str(&v),
+            Err(e) => match e.kind {
+                ErrorKind::NoSources => eprintln!("WARNING: {e}. Skipping `{}`", name),
+                #[allow(unreachable_patterns)]
+                _ => {
+                    return Err(e);
+                }
+            },
+        }
+    }
+
+    Ok(ret)
+}
+
+pub fn write_ninja_file(filename: &str, content: &[u8]) -> std::io::Result<()> {
+    let file = OpenOptions::new()
+        .write(true)
+        .truncate(true)
+        .create(true)
+        .open(filename)?;
+
+    let mut writer = BufWriter::new(file);
+    writer.write(content)?;
+    Ok(())
+}

src/deser.rs

@@ -3,7 +3,7 @@ use std::collections::HashMap;
 
 #[derive(Debug, Clone, Deserialize)]
 #[serde(deny_unknown_fields)]
-pub struct ParsedTarget {
+pub struct DeserTarget {
     pub outfile: Option<String>,
     pub compiler: Option<String>,
     pub compiler_flags: Option<Vec<String>>,
@@ -11,28 +11,31 @@ pub struct ParsedTarget {
     pub linker_flags: Option<Vec<String>>,
     pub linker_libs: Option<Vec<String>>,
     pub sources: Option<Vec<String>>,
-    pub opts: Option<ParsedTargetOptions>,
+    pub opts: Option<DeserTargetOptions>,
 }
 
 #[derive(Debug, Clone, Deserialize)]
 #[serde(deny_unknown_fields)]
-pub struct ParsedTargetOptions {
+pub struct DeserTargetOptions {
     pub inherit: Option<bool>,
     pub inherit_from: Option<String>,
+    pub depend_on: Option<Vec<String>>,
     pub default: Option<bool>,
 }
 
 #[derive(Debug, Clone, Deserialize)]
 #[serde(deny_unknown_fields)]
-pub struct ParsedConfigTable {
+pub struct DeserConfig {
     pub build_dir: Option<String>,
     pub compile_commands: Option<bool>,
     pub compile_commands_target: Option<String>,
 }
 
+pub type DeserTargetList = HashMap<String, DeserTarget>;
+
 #[derive(Debug, Clone, Deserialize)]
 #[serde(deny_unknown_fields)]
-pub struct NgenToml {
+pub struct DeserNgenToml {
-    pub config: Option<ParsedConfigTable>,
+    pub config: Option<DeserConfig>,
-    pub targets: Option<HashMap<String, ParsedTarget>>,
+    pub targets: Option<DeserTargetList>,
 }

src/main.rs

@@ -1,18 +1,16 @@
-use clap::Parser;
 use core::panic;
-use std::collections::HashMap;
+use std::{collections::HashMap, env::args, fs::read_to_string, process::exit};
-use std::fs::{read_to_string, OpenOptions};
-use std::io::{BufWriter, Write};
-use std::process::exit;
 
-mod ngen_toml;
+use clap::Parser;
-use ngen_toml::*;
 
-mod parsed_config_processing;
+mod content_generation;
-use parsed_config_processing::*;
+mod deser;
+mod parse_deser;
+mod validation;
 
-mod file_writing;
+use content_generation::*;
-use file_writing::*;
+use deser::*;
+use parse_deser::*;
 
 /// ngen is a build file generator for the ninja build system.
 #[derive(Parser)]
@@ -32,118 +30,72 @@ struct Args {
 fn main() {
     let args = Args::parse();
 
-    let config_file = read_to_string(&args.config_file)
+    let ngen_toml = read_to_string(&args.config_file)
         .unwrap_or_else(|e| panic!("error reading config file `{}`: {e}", args.config_file));
-    let toml_config: NgenToml = toml::from_str(&config_file)
+    let deser_ngen_toml: DeserNgenToml = toml::from_str(&ngen_toml)
         .unwrap_or_else(|e| panic!("error parsing config file `{}`: {e}", args.config_file));
 
-    let config_table: ConfigTable = match &toml_config.config {
+    let target_option_list: TargetOptionList;
-        Some(v) => ConfigTable::from_parsed_config(&v).unwrap_or_else(|e| panic!("{e}")),
+    let deser_target_list: &DeserTargetList;
-        None => ConfigTable::get_default(),
+    match &deser_ngen_toml.targets {
+        Some(v) => {
+            target_option_list = TargetOptionList::from(v);
+            deser_target_list = &v;
+        }
+        None => panic!("no targets provided, nothing to do. Exiting"),
     };
 
-    let all_parsed_targets: &HashMap<String, ParsedTarget> = match &toml_config.targets {
+    target_option_list
-        Some(v) => v,
+        .check_for_dependency_cycle()
-        None => panic!(
+        .unwrap_or_else(|e| panic!("{e}. cannont continue. Exiting"));
-            "{}",
+
-            ConfigurationError {
+    let inheritance_order = target_option_list
-                message: "no targets found, nothing to do. Exiting".to_string()
+        .get_inheritance_order()
+        .unwrap_or_else(|e| panic!("{e}. cannot continue. Exiting"));
+
+    let mut target_list: TargetList = TargetList(HashMap::new());
+    for order in &inheritance_order {
+        for name in order.into_iter().rev() {
+            let opts = target_option_list.0.get(name as &str).unwrap();
+            let deser = deser_target_list.get(name as &str).unwrap();
+
+            let parent: Option<&Target>;
+            if opts.inherit && (name != opts.inherit_from) {
+                parent = Some(target_list.0.get(opts.inherit_from as &str).unwrap());
+            } else {
+                parent = None;
             }
-        ),
+
+            target_list.0.insert(name, Target::new(opts, deser, parent));
+        }
+    }
+
+    target_list
+        .check_if_any_sources_are_provided()
+        .unwrap_or_else(|e| panic!("{e}, nothing to do. Exiting"));
+
+    let config = match &deser_ngen_toml.config {
+        Some(v) => Config::from(v),
+        None => Config::get_default(),
     };
 
-    let mut sources_found = false;
+    config
-    for target in all_parsed_targets.values() {
+        .check_compile_commands_target(&target_list)
-        if let Some(_) = target.sources {
+        .unwrap_or_else(|e| panic!("{e}"));
-            sources_found = true;
-            break;
-        }
-    }
-    if !sources_found {
-        panic!(
-            "{}",
-            ConfigurationError {
-                message: "no targets have any sources, nothing to do. Exiting".to_string()
-            }
-        );
-    }
-
-    let mut targets: HashMap<&str, Target> = HashMap::new();
-    for (name, parsed_target) in all_parsed_targets {
-        if let Some(_) = targets.get(name as &str) {
-            continue;
-        }
-        let mut inheritance_chain: HashMap<&str, &str> = HashMap::new();
-        match Target::from_parsed_target(
-            parsed_target,
-            name,
-            all_parsed_targets,
-            &targets,
-            &mut inheritance_chain,
-        ) {
-            Ok(v) => {
-                targets.extend(v.into_iter());
-            }
-            Err(e) => panic!("{e}"),
-        }
-    }
 
     if let Some(filename) = &args.write_compile_commands {
-        let target = match targets.get(config_table.compile_commands_target) {
+        let name = config.compile_commands_target;
-            Some(v) => v,
+        let target = target_list.0.get(name).unwrap();
-            None => panic!(
+        let content = create_compile_commands_content(name, target, &config)
-                "{}",
+            .unwrap_or_else(|e| panic!("{e}"));
-                ContentGenerationError {
+        write_compile_commands(filename, content.as_bytes()).unwrap_or_else(|e| {
-                    message: format!(
+            panic!("could not write compile commands file `{}`: {e}", filename)
-                        "compile_commands_target is set to `{0}`, however target `{0}` does not exist.",
-                        config_table.compile_commands_target
-                    )
-                }
-            ),
-        };
-        let compile_commands = match gen_compile_commands(
-            config_table.compile_commands_target,
-            &target,
-            &config_table,
-        ) {
-            Ok(v) => v,
-            Err(e) => panic!("{e}"),
-        };
-        let mut comp_cmds_file = OpenOptions::new()
-            .write(true)
-            .truncate(true)
-            .create(true)
-            .open(&filename)
-            .unwrap_or_else(|e| panic!("error opening compile commands file `{}`: {e}", filename));
-        comp_cmds_file
-            .write_all(&compile_commands.as_bytes())
-            .unwrap_or_else(|e| {
-                panic!("error writing to compile commands file `{}`: {e}", filename)
         });
-
-        // no need to generate the ninja file
         exit(0);
     }
 
-    let ninjafile = OpenOptions::new()
+    let ninja_file_content =
-        .write(true)
+        create_ninja_file_content(&target_list, &config, &args).unwrap_or_else(|e| panic!("{e}"));
-        .truncate(true)
+    write_ninja_file(&args.output_file, ninja_file_content.as_bytes())
-        .create(true)
+        .unwrap_or_else(|e| panic!("could not write ninja file `{}`: {e}", args.output_file));
-        .open(&args.output_file)
-        .unwrap_or_else(|e| panic!("error opening ninja file `{}`: {e}", args.output_file));
-
-    let mut ninjafile_writer = BufWriter::new(ninjafile);
-    ninjafile_writer
-        .write(&gen_ninja_header(&config_table, &args).as_bytes())
-        .unwrap_or_else(|e| panic!("error writing to ninja file `{}`: {e}", args.output_file));
-    for (name, target) in &targets {
-        match gen_ninja_target(name, target) {
-            Ok(v) => {
-                ninjafile_writer.write(&v.as_bytes()).unwrap_or_else(|e| {
-                    panic!("error writing to ninja file `{}`: {e}", args.output_file)
-                });
-            }
-            Err(e) => eprintln!("WARNING: {e}. `{}` will NOT be generated", name),
-        }
-    }
 }

src/parse_deser/config.rs

@@ -1,39 +1,38 @@
-use super::*;
+use crate::deser::*;
-use crate::ngen_toml::*;
 
 #[derive(Debug, Clone)]
-pub struct ConfigTable<'a> {
+pub struct Config<'a> {
     pub build_dir: &'a str,
     pub compile_commands: bool,
     pub compile_commands_target: &'a str,
 }
 
-impl<'a> ConfigTable<'a> {
+impl<'a> From<&'a DeserConfig> for Config<'a> {
+    fn from(value: &'a DeserConfig) -> Self {
+        let mut ret = Self::get_default();
+
+        if let Some(v) = &value.build_dir {
+            ret.build_dir = v;
+        }
+
+        if let Some(v) = &value.compile_commands {
+            ret.compile_commands = *v;
+        }
+
+        if let Some(v) = &value.compile_commands_target {
+            ret.compile_commands_target = v;
+        }
+
+        ret
+    }
+}
+
+impl<'a> Config<'a> {
     pub fn get_default() -> Self {
-        ConfigTable {
+        Self {
             build_dir: "build",
             compile_commands: false,
             compile_commands_target: "main",
         }
     }
-
-    pub fn from_parsed_config(
-        parsed_config_table: &'a ParsedConfigTable,
-    ) -> Result<Self, ConfigurationError> {
-        let mut ret = Self::get_default();
-
-        if let Some(v) = &parsed_config_table.build_dir {
-            ret.build_dir = v;
-        }
-
-        if let Some(v) = &parsed_config_table.compile_commands {
-            ret.compile_commands = *v;
-        }
-
-        if let Some(v) = &parsed_config_table.compile_commands_target {
-            ret.compile_commands_target = v;
-        }
-
-        Ok(ret)
-    }
 }

src/parse_deser/mod.rs

@@ -0,0 +1,11 @@
+pub mod config;
+pub mod target;
+pub mod target_list;
+pub mod target_options;
+pub mod target_options_list;
+
+pub use config::*;
+pub use target::*;
+pub use target_list::*;
+pub use target_options::*;
+pub use target_options_list::*;

src/parse_deser/target.rs

@@ -0,0 +1,99 @@
+use super::*;
+use crate::deser::*;
+
+#[derive(Debug, Clone)]
+pub struct Target<'a> {
+    pub outfile: &'a str,
+    pub compiler: &'a str,
+    pub compiler_flags: Vec<&'a str>,
+    pub linker: &'a str,
+    pub linker_flags: Vec<&'a str>,
+    pub linker_libs: Vec<&'a str>,
+    pub sources: Vec<&'a str>,
+    pub opts: TargetOptions<'a>,
+}
+
+impl<'a> Target<'a> {
+    pub fn new(
+        opts: &TargetOptions<'a>,
+        deser: &'a DeserTarget,
+        parent: Option<&Target<'a>>,
+    ) -> Self {
+        let mut ret = Self::get_default();
+
+        ret.opts = opts.clone();
+
+        if let Some(parent) = parent {
+            if let None = deser.outfile {
+                ret.outfile = parent.outfile;
+            }
+            if let None = deser.compiler {
+                ret.compiler = parent.compiler;
+            }
+            if let None = deser.linker {
+                ret.linker = parent.linker;
+            }
+            for string in parent.compiler_flags.clone() {
+                ret.compiler_flags.push(string);
+            }
+            for string in parent.linker_flags.clone() {
+                ret.linker_flags.push(string);
+            }
+            for string in parent.linker_libs.clone() {
+                ret.linker_libs.push(string);
+            }
+            for string in parent.sources.clone() {
+                ret.sources.push(string);
+            }
+        }
+
+        if let Some(v) = &deser.outfile {
+            ret.outfile = v;
+        }
+        if let Some(v) = &deser.compiler {
+            ret.compiler = v;
+        }
+        if let Some(v) = &deser.compiler_flags {
+            for string in v {
+                ret.compiler_flags.push(string);
+            }
+        }
+        if let Some(v) = &deser.linker {
+            ret.linker = v;
+        } else {
+            if let Some(v) = &deser.compiler {
+                ret.linker = v;
+            }
+        }
+        if let Some(v) = &deser.linker_flags {
+            for string in v {
+                ret.linker_flags.push(string);
+            }
+        }
+        if let Some(v) = &deser.linker_libs {
+            for string in v {
+                ret.linker_libs.push(string);
+            }
+        }
+        if let Some(v) = &deser.sources {
+            for string in v {
+                ret.sources.push(string);
+            }
+        }
+
+        ret
+    }
+
+    pub fn get_default() -> Self {
+        Target {
+            outfile: "a.out",
+            compiler: "cc",
+            compiler_flags: vec![],
+            linker: "cc",
+            linker_flags: vec![],
+            linker_libs: vec![],
+            sources: vec![],
+            opts: TargetOptions::get_default(),
+        }
+    }
+}

src/parse_deser/target_list.rs

@@ -0,0 +1,6 @@
+use super::*;
+use crate::deser::*;
+use std::collections::HashMap;
+
+#[derive(Debug, Clone)]
+pub struct TargetList<'a>(pub HashMap<&'a str, Target<'a>>);

src/parse_deser/target_options.rs

@@ -0,0 +1,46 @@
+use crate::deser::*;
+
+#[derive(Debug, Clone)]
+pub struct TargetOptions<'a> {
+    pub inherit: bool,
+    pub inherit_from: &'a str,
+    pub default: bool,
+    pub depend_on: Vec<&'a str>,
+}
+
+impl<'a> From<&'a DeserTargetOptions> for TargetOptions<'a> {
+    fn from(value: &'a DeserTargetOptions) -> Self {
+        let mut ret = Self::get_default();
+
+        if let Some(v) = &value.inherit {
+            ret.inherit = *v; // dereference the bool to copy it
+        }
+
+        if let Some(v) = &value.inherit_from {
+            ret.inherit_from = v;
+        }
+
+        if let Some(v) = &value.default {
+            ret.default = *v; // dereference the bool to copy it
+        }
+
+        if let Some(v) = &value.depend_on {
+            for string in v {
+                ret.depend_on.push(string);
+            }
+        }
+
+        ret
+    }
+}
+
+impl<'a> TargetOptions<'a> {
+    pub fn get_default() -> Self {
+        Self {
+            inherit: true,
+            inherit_from: "main",
+            default: false,
+            depend_on: vec![],
+        }
+    }
+}

src/parse_deser/target_options_list.rs

@@ -0,0 +1,22 @@
+use super::*;
+use crate::deser::*;
+use std::collections::HashMap;
+
+#[derive(Debug, Clone)]
+pub struct TargetOptionList<'a>(pub HashMap<&'a str, TargetOptions<'a>>);
+
+impl<'a> From<&'a DeserTargetList> for TargetOptionList<'a> {
+    fn from(value: &'a DeserTargetList) -> Self {
+        let mut ret: Self = TargetOptionList(HashMap::new());
+
+        for (name, target) in value {
+            if let Some(v) = &target.opts {
+                ret.0.insert(name, TargetOptions::from(v));
+            } else {
+                ret.0.insert(name, TargetOptions::get_default());
+            }
+        }
+
+        ret
+    }
+}

src/parsed_config_processing/configuration_error.rs

@@ -1,12 +0,0 @@
-use std::fmt::Display;
-
-#[derive(Debug)]
-pub struct ConfigurationError {
-    pub message: String,
-}
-
-impl Display for ConfigurationError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "configuration error: {}", self.message)
-    }
-}

src/parsed_config_processing/mod.rs

@@ -1,9 +0,0 @@
-pub mod config_table;
-pub mod configuration_error;
-pub mod target;
-pub mod target_options;
-
-pub use config_table::*;
-pub use configuration_error::*;
-pub use target::*;
-pub use target_options::*;

src/parsed_config_processing/target.rs

@@ -1,150 +0,0 @@
-use core::str;
-use std::collections::HashMap;
-
-use super::*;
-use crate::ngen_toml::*;
-
-#[derive(Debug, Clone)]
-pub struct Target<'a> {
-    pub outfile: &'a str,
-    pub compiler: &'a str,
-    pub compiler_flags: Vec<&'a str>,
-    pub linker: &'a str,
-    pub linker_flags: Vec<&'a str>,
-    pub linker_libs: Vec<&'a str>,
-    pub sources: Vec<&'a str>,
-    pub opts: TargetOptions<'a>,
-}
-
-impl<'a> Target<'a> {
-    pub fn get_default(
-        ) -> Self {
-        Target {
-            outfile: "a.out",
-            compiler: "cc",
-            compiler_flags: vec![],
-            linker: "cc",
-            linker_flags: vec![],
-            linker_libs: vec![],
-            sources: vec![],
-            opts: TargetOptions::get_default(),
-        }
-    }
-    pub fn from_parsed_target(
-        parsed_target: &'a ParsedTarget,
-        name: &'a str,
-        all_parsed_targets: &'a HashMap<String, ParsedTarget>,
-        all_targets: &HashMap<&'a str, Target<'a>>,
-        inheritance_chain: &mut HashMap<&'a str, &'a str>
-    ) -> Result<HashMap<&'a str, Target<'a>>, ConfigurationError> {
-        let mut retmap: HashMap<&str, Target> = HashMap::new();
-        let mut ret = Self::get_default();
-
-        if ret.opts.inherit_from == name {
-            ret.opts.inherit = false;
-        }
-
-        if let Some(v) = &parsed_target.opts {
-            ret.opts = TargetOptions::from_parsed_target_options(v)?;
-        }
-
-        if ret.opts.inherit {
-            let inherit_target: Target;
-
-            match all_targets.get(ret.opts.inherit_from) {
-                Some(v) => {
-                    inherit_target = v.clone()
-                }
-                None => {
-                    match all_parsed_targets.get(ret.opts.inherit_from) {
-                        Some(v) => {
-                            let inherited_targets: HashMap<&str, Target>;
-                            if let Some(_) = inheritance_chain.get(ret.opts.inherit_from) {
-                                let mut message = format!("inheritance dependency cylce detected: ");
-                                for (targ_name, depends_on) in inheritance_chain {
-                                    message.push_str(&format!("`{}` depends on `{}`, ", targ_name, depends_on));
-                                }
-                                message.push_str(&format!("and `{}` depends on `{}`", name, ret.opts.inherit_from));
-                                return Err(ConfigurationError { message });
-                            }
-                            inheritance_chain.insert(name, ret.opts.inherit_from);
-                            inherited_targets = Self::from_parsed_target(v, ret.opts.inherit_from, all_parsed_targets, all_targets, inheritance_chain)?;
-                            inherit_target = inherited_targets.get(ret.opts.inherit_from).unwrap().clone();
-                            retmap.extend(inherited_targets.into_iter());
-                        }
-                        None => {
-                            return Err(ConfigurationError { 
-                                message: 
-                                    format!("target `{0}` trying to inherit from target `{1}`, but target `{1}` does not exist", 
-                                            name, 
-                                            ret.opts.inherit_from)
-                            });
-                        }
-                    }
-                }
-            }
-
-
-            if let None = parsed_target.outfile {
-                ret.outfile = inherit_target.outfile;
-            }
-            if let None = parsed_target.compiler {
-                ret.compiler = inherit_target.compiler;
-            }
-            if let None = parsed_target.linker {
-                ret.linker = inherit_target.linker;
-            }
-
-            for string in inherit_target.compiler_flags {
-                ret.compiler_flags.push(string);
-            }
-            for string in inherit_target.linker_flags {
-                ret.linker_flags.push(string);
-            }
-            for string in inherit_target.linker_libs {
-                ret.linker_libs.push(string);
-            }
-            for string in inherit_target.sources {
-                ret.sources.push(string);
-            }
-        }
-
-        if let Some(v) = &parsed_target.outfile {
-            ret.outfile = v;
-        }
-        if let Some(v) = &parsed_target.compiler {
-            ret.compiler = v;
-        }
-        if let Some(v) = &parsed_target.compiler_flags {
-            for string in v {
-                ret.compiler_flags.push(string);
-            }
-        }
-        if let Some(v) = &parsed_target.linker {
-            ret.linker = v;
-        } else {
-            if let Some(v) = &parsed_target.compiler {
-                ret.linker = v;
-            }
-        }
-        if let Some(v) = &parsed_target.linker_flags {
-            for string in v {
-                ret.linker_flags.push(string);
-            }
-        }
-        if let Some(v) = &parsed_target.linker_libs {
-            for string in v {
-                ret.linker_libs.push(string);
-            }
-        }
-        if let Some(v) = &parsed_target.sources {
-            for string in v {
-                ret.sources.push(string);
-            }
-        }
-
-        retmap.insert(name, ret);
-
-        Ok(retmap)
-    }
-}

src/parsed_config_processing/target_options.rs

@@ -1,38 +0,0 @@
-use super::*;
-use crate::ngen_toml::*;
-
-#[derive(Debug, Clone)]
-pub struct TargetOptions<'a> {
-    pub inherit: bool,
-    pub inherit_from: &'a str,
-    pub default: bool,
-}
-
-impl<'a> TargetOptions<'a> {
-    pub fn get_default() -> Self {
-        TargetOptions {
-            inherit: true,
-            inherit_from: "main",
-            default: false,
-        }
-    }
-    pub fn from_parsed_target_options(
-        parsed_target_options: &'a ParsedTargetOptions,
-    ) -> Result<Self, ConfigurationError> {
-        let mut ret = Self::get_default();
-
-        if let Some(v) = &parsed_target_options.inherit {
-            ret.inherit = *v;
-        }
-
-        if let Some(v) = &parsed_target_options.inherit_from {
-            ret.inherit_from = v;
-        }
-
-        if let Some(v) = &parsed_target_options.default {
-            ret.default = *v;
-        }
-
-        Ok(ret)
-    }
-}

src/validation.rs

@@ -0,0 +1,188 @@
+use std::{collections::HashMap, fmt::Display};
+
+use crate::parse_deser::*;
+
+pub enum ErrorKind {
+    NoSources,
+    DependencyDoesNotExist,
+    DependencyCycle,
+    ParentDoesNotExist,
+    InheritanceCycle,
+    CompileCmdsTargetDoesNotExist,
+}
+
+pub struct Error {
+    pub kind: ErrorKind,
+    pub message: String,
+}
+
+impl Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "configuration error: {}", self.message)
+    }
+}
+
+type Result<T> = std::result::Result<T, Error>;
+
+type Chain<'a> = HashMap<&'a str, &'a str>;
+
+fn print_chain(chain: &Chain, start: &str, connector: &str) -> String {
+    let mut ret = "target".to_string();
+    let mut i = 0;
+    let mut start = start;
+    while i < chain.len() {
+        let dep = chain.get(start).unwrap();
+        if i == chain.len() - 1 {
+            ret.push_str(&format!(" but target `{}` {} `{}`", start, connector, dep));
+            break;
+        }
+        ret.push_str(&format!(" `{}` {} `{}`,", start, connector, dep));
+        start = dep;
+        i += 1;
+    }
+
+    ret
+}
+
+impl<'a> TargetList<'a> {
+    pub fn check_if_any_sources_are_provided(&self) -> Result<()> {
+        let mut sources_found = false;
+        for target in self.0.values() {
+            if !target.sources.is_empty() {
+                sources_found = true;
+                break;
+            }
+        }
+        if sources_found {
+            Ok(())
+        } else {
+            Err(Error {
+                kind: ErrorKind::NoSources,
+                message: "no targets have any sources".to_string(),
+            })
+        }
+    }
+}
+
+impl<'a> TargetOptionList<'a> {
+    fn check_target_dep(
+        &self,
+        opts: &TargetOptions<'a>,
+        name: &'a str,
+        dep_chain: &mut Chain<'a>,
+    ) -> Result<()> {
+        for dep in opts.depend_on.clone() {
+            match self.0.get(dep) {
+                Some(v) => {
+                    dep_chain.insert(name, dep);
+                    if let Some(_) = dep_chain.get(dep) {
+                        return Err(Error {
+                            kind: ErrorKind::DependencyCycle,
+                            message: format!(
+                                "dependency cycle detected: {}",
+                                print_chain(dep_chain, name, "depends on")
+                            ),
+                        });
+                    }
+                    self.check_target_dep(v, dep, dep_chain)?;
+                    let _ = dep_chain.remove(name);
+                }
+                None => {
+                    return Err(Error {
+                        kind: ErrorKind::DependencyDoesNotExist,
+                        message: format!(
+                            "target `{0}` depends on `{1}`, but target `{1}` does not exist",
+                            name, dep
+                        ),
+                    });
+                }
+            }
+        }
+        Ok(())
+    }
+
+    pub fn check_for_dependency_cycle(&self) -> Result<()> {
+        for (name, opts) in &self.0 {
+            let mut dep_chain: Chain = HashMap::new();
+            self.check_target_dep(opts, name, &mut dep_chain)?;
+        }
+        Ok(())
+    }
+
+    fn check_target_parent(
+        &self,
+        opts: &TargetOptions<'a>,
+        name: &'a str,
+        dep_chain: &mut Chain<'a>,
+    ) -> Result<()> {
+        let inherit = opts.inherit_from;
+        if name == inherit {
+            return Ok(());
+        }
+        match self.0.get(inherit) {
+            Some(v) => {
+                dep_chain.insert(name, inherit);
+                if let Some(_) = dep_chain.get(inherit) {
+                    return Err(Error {
+                        kind: ErrorKind::InheritanceCycle,
+                        message: format!(
+                            "inheritance cycle detected: {}",
+                            print_chain(dep_chain, name, "inherits from")
+                        ),
+                    });
+                }
+                self.check_target_parent(v, inherit, dep_chain)?;
+            }
+            None => {
+                return Err(Error {
+                    kind: ErrorKind::ParentDoesNotExist,
+                    message: format!(
+                        "target `{0}` inherits from `{1}`, but target `{1}` does not exist",
+                        name, inherit
+                    ),
+                });
+            }
+        }
+        Ok(())
+    }
+
+    pub fn get_inheritance_order(&self) -> Result<Vec<Vec<String>>> {
+        let mut ret: Vec<Vec<String>> = vec![];
+        for (name, opts) in &self.0 {
+            if !opts.inherit {
+                ret.push(vec![name.to_string()]);
+                continue;
+            }
+            let mut dep_chain: Chain = HashMap::new();
+
+            self.check_target_parent(opts, name, &mut dep_chain)?;
+
+            let mut order: Vec<String> = vec![name.to_string()];
+            let mut i = 0;
+            while let Some(v) = dep_chain.get(&order[i] as &str) {
+                order.push(v.to_string());
+                i += 1;
+            }
+            ret.push(order);
+        }
+        Ok(ret)
+    }
+}
+
+impl<'a> Config<'a> {
+    pub fn check_compile_commands_target(&self, target_list: &TargetList) -> Result<()> {
+        if !self.compile_commands {
+            return Ok(());
+        }
+        match target_list.0.get(self.compile_commands_target) {
+            Some(_) => Ok(()),
+            None => Err(Error {
+                kind: ErrorKind::CompileCmdsTargetDoesNotExist,
+                message: format!(
+                    "compile commands target `{}` does not exist",
+                    self.compile_commands_target
+                ),
+            }),
+        }
+    }
+}

test.txt

@@ -0,0 +1,92 @@
+TargetList(
+    {
+        "three": Target {
+            outfile: "foobar",
+            compiler: "gcc",
+            compiler_flags: [
+                "-Wall",
+                "-Wextra",
+            ],
+            linker: "gcc",
+            linker_flags: [],
+            linker_libs: [],
+            sources: [
+                "main.c",
+            ],
+            opts: TargetOptions {
+                inherit: true,
+                inherit_from: "two",
+                default: false,
+                depend_on: [],
+            },
+        },
+        "one": Target {
+            outfile: "foobar",
+            compiler: "gcc",
+            compiler_flags: [],
+            linker: "gcc",
+            linker_flags: [],
+            linker_libs: [],
+            sources: [
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+            ],
+            opts: TargetOptions {
+                inherit: true,
+                inherit_from: "main",
+                default: false,
+                depend_on: [],
+            },
+        },
+        "two": Target {
+            outfile: "foobar",
+            compiler: "gcc",
+            compiler_flags: [
+                "-Wall",
+                "-Wall",
+            ],
+            linker: "gcc",
+            linker_flags: [],
+            linker_libs: [],
+            sources: [
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+            ],
+            opts: TargetOptions {
+                inherit: true,
+                inherit_from: "one",
+                default: false,
+                depend_on: [],
+            },
+        },
+        "main": Target {
+            outfile: "foobar",
+            compiler: "cc",
+            compiler_flags: [],
+            linker: "cc",
+            linker_flags: [],
+            linker_libs: [],
+            sources: [
+                "main.c",
+                "main.c",
+                "main.c",
+                "main.c",
+            ],
+            opts: TargetOptions {
+                inherit: false,
+                inherit_from: "main",
+                default: false,
+                depend_on: [],
+            },
+        },
+    },
+)