Add Bazel CrateId hash method

mbedtls/Cargo.toml

@@ -4,7 +4,7 @@ name = "mbedtls"
 # we decided not to support.
 version = "0.12.3"
 authors = ["Jethro Beekman <[email protected]>"]
-build = "build.rs"
+build = "build/build.rs"
 edition = "2018"
 license = "Apache-2.0 OR GPL-2.0-or-later"
 description = """

mbedtls/build.rs → mbedtls/build/build.rs

@@ -6,6 +6,8 @@
  * option. This file may not be copied, modified, or distributed except
  * according to those terms. */
 
+mod crate_id;
+
 use std::collections::{HashMap, HashSet};
 use std::env;
 
@@ -15,13 +17,27 @@ use rustc_version::Channel;
 // If there's a panic in this code block, that means Cargo's way of running the
 // build script has changed, and this code should be updated to handle the new
 // case.
+// Since Bazel does not use Cargo to generate Crate Metadata hash we need to implement a separate one for it.
 fn get_compilation_metadata_hash() -> String {
     let out_dir: std::path::PathBuf = std::env::var_os("OUT_DIR").unwrap().into();
     let mut out_dir_it = out_dir.iter().rev();
-    assert_eq!(out_dir_it.next().unwrap(), "out");
-    let crate_ = out_dir_it.next().unwrap().to_string_lossy();
-    assert!(crate_.starts_with("mbedtls-"));
-    crate_[8..].to_owned()
+    let next = out_dir_it.next().unwrap();
+
+    if next == "out" {
+        let crate_ = out_dir_it.next().unwrap().to_string_lossy();
+        assert!(crate_.starts_with("mbedtls-"));
+        return crate_[8..].to_owned();
+    } else if next == "_bs.out_dir" {
+        let compiler_version = rustc_version::version().expect("Failed to get rustc version").to_string();
+        let version = env!("CARGO_PKG_VERSION");
+        let versioned_string = format!("mbedtls_{}", version);
+        let metadata = vec!["".to_string()];
+        let stable_crate_id = crate_id::StableCrateId::new(&versioned_string, false, metadata, compiler_version);
+
+        return stable_crate_id.to_string();
+    } else {
+        panic!("Unexpected directory structure: {:?}", next);
+    }
 }
 
 fn main() {

mbedtls/build/crate_id.rs

@@ -0,0 +1,52 @@
+use std::fmt;
+
+pub struct StableCrateId(u64);
+
+impl StableCrateId {
+    pub fn new(
+        crate_name: &str,
+        is_exe: bool,
+        mut metadata: Vec<String>,
+        cfg_version: String,
+    ) -> StableCrateId {
+        use std::collections::hash_map::DefaultHasher;
+        use std::hash::{Hash, Hasher};
+
+        let mut hasher = DefaultHasher::new();
+        crate_name.hash(&mut hasher);
+
+        metadata.sort();
+        metadata.dedup();
+
+        hasher.write(b"metadata");
+        for s in &metadata {
+            hasher.write_usize(s.len());
+            hasher.write(s.as_bytes());
+        }
+
+        hasher.write(if is_exe { b"exe" } else { b"lib" });
+
+        hasher.write(cfg_version.as_bytes());
+
+        StableCrateId(hasher.finish() as u64)
+    }
+
+    pub fn as_u64(self) -> u64 {
+        self.0
+    }
+}
+
+// Implement the LowerHex trait for StableCrateId
+impl fmt::LowerHex for StableCrateId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::LowerHex::fmt(&self.0, f)
+    }
+}
+
+impl fmt::Display for StableCrateId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Implement the formatting logic here
+        // Example: Display the inner value as a hexadecimal string
+        write!(f, "{:x}", self.0)
+    }
+}