Initial commit: noxis JVM bytecode obfuscator

Workspace of 9 crates (noxis, noxis-core, noxis-classfile, noxis-analysis,
noxis-passes, noxis-runtime, noxis-jar, noxis-verify, noxis-structure-check).
AGPL-3.0-only license, Rust 2024 edition, unsafe_code denied.

crates/noxis-verify/src/metrics.rs

@@ -0,0 +1,93 @@
+//! Метрики программы: счётчики, раздувание, стабильность маппингов.
+
+use serde::Serialize;
+use noxis_classfile::{Const, Insn, Program};
+use noxis_core::Mapping;
+
+/// Счётчики программы (для отчёта и бюджетов).
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize)]
+pub struct ProgramStats {
+    pub classes: usize,
+    pub methods: usize,
+    pub fields: usize,
+    pub insns: usize,
+    pub strings: usize,
+    pub resources: usize,
+}
+
+/// Посчитать статистику по программе.
+pub fn program_stats(program: &Program) -> ProgramStats {
+    let mut stats = ProgramStats {
+        classes: program.classes.len(),
+        resources: program.resources.len(),
+        ..ProgramStats::default()
+    };
+    for class in &program.classes {
+        stats.fields += class.fields.len();
+        stats.methods += class.methods.len();
+        for method in &class.methods {
+            let Some(code) = method.code.as_ref() else {
+                continue;
+            };
+            stats.insns += code.insns.len();
+            stats.strings += code
+                .insns
+                .iter()
+                .filter(|insn| matches!(insn, Insn::Const(Const::String(_))))
+                .count();
+        }
+    }
+    stats
+}
+
+/// Коэффициент раздувания (`after / before`).
+pub fn inflation_ratio(before_bytes: u64, after_bytes: u64) -> f64 {
+    if before_bytes == 0 {
+        return f64::INFINITY;
+    }
+    after_bytes as f64 / before_bytes as f64
+}
+
+/// Раздувание в бюджете (`max_ratio`, например `1.5` = +50%).
+pub fn check_inflation(before_bytes: u64, after_bytes: u64, max_ratio: f64) -> Result<(), String> {
+    let ratio = inflation_ratio(before_bytes, after_bytes);
+    if ratio > max_ratio {
+        return Err(format!(
+            "раздувание {ratio:.2} сверх бюджета {max_ratio:.2}"
+        ));
+    }
+    Ok(())
+}
+
+/// Маппинги обязаны меняться между сборками (иначе сид не работает).
+pub fn mappings_changed(before: &Mapping, after: &Mapping) -> bool {
+    before != after
+}
+
+#[cfg(test)]
+mod tests {
+    #![allow(clippy::expect_used, clippy::unwrap_used)]
+
+    use super::*;
+
+    #[test]
+    fn empty_program_stats_are_zero() {
+        let stats = program_stats(&Program::default());
+        assert_eq!(stats, ProgramStats::default());
+        assert_eq!(stats.classes, 0);
+    }
+
+    #[test]
+    fn inflation_math() {
+        assert!((inflation_ratio(100, 150) - 1.5).abs() < f64::EPSILON);
+        assert!(inflation_ratio(0, 10).is_infinite());
+        assert!(check_inflation(100, 120, 1.5).is_ok());
+        assert!(check_inflation(100, 200, 1.5).is_err());
+    }
+
+    #[test]
+    fn identical_mappings_are_stable() {
+        let mapping = Mapping::default();
+        assert!(!mappings_changed(&mapping, &mapping));
+    }
+}