Merge pull request #181 from baoyachi/issue/179

Make using the CARGO_METADATA object simpler

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "shadow-rs"
-version = "0.33.0"
+version = "0.34.0"
 authors = ["baoyachi <[email protected]>"]
 edition = "2021"
 description = "A build-time information stored in your rust project"
@@ -19,8 +19,8 @@ all-features = true
 
 [dependencies]
 is_debug = "1.0.1"
-const_format = "0.2.22"
-time = { version = "0.3.11", features = ["formatting", "local-offset", "parsing"] }
+const_format = { version = "0.2.22", default-features = false }
+time = { version = "0.3.11", features = ["formatting", "local-offset", "parsing"], default-features = false }
 
 
 #! Optional Dependencies:
@@ -33,8 +33,12 @@ tzdb = { version = "0.6.0", optional = true, default-features = false, features
 
 document-features = { version = "0.2", optional = true }
 
+cargo_metadata = { version = "0.18.1", optional = true, default-features = false }
+serde_json = { version = "1", default-features = false, optional = true }
+
 [features]
 default = ["git2", "tzdb"]
+metadata = ["cargo_metadata", "serde_json"]
 
 [dev-dependencies]
 winnow = "0.6"

example_shadow/Cargo.toml

@@ -9,7 +9,7 @@ build = "build.rs"
 
 [dependencies]
 clap = "4.0.1"
-shadow-rs = { path = "../" }
+shadow-rs = { path = "../",features = ["metadata"] }
 
 [build-dependencies]
 shadow-rs = { path = "../" }

example_shadow/build.rs

@@ -1,3 +1,5 @@
 fn main() -> shadow_rs::SdResult<()> {
-    shadow_rs::new()
+    // shadow_rs::new()
+
+    shadow_rs::new_deny(Default::default())
 }

example_shadow/src/main.rs

@@ -57,4 +57,6 @@ pub fn print_build() {
     println!("build_time_2822:{}", build::BUILD_TIME_2822);
     println!("build_time_3339:{}", build::BUILD_TIME_3339);
     println!("build_rust_channel:{}", build::BUILD_RUST_CHANNEL);
+
+    println!("{:?}", build::cargo_metadata().unwrap())
 }

src/gen_const.rs

@@ -1,3 +1,5 @@
+use crate::{Shadow, CARGO_CLIPPY_ALLOW_ALL, CARGO_METADATA};
+
 macro_rules! gen_const {
     ($fn_name:ident, $fn_body:expr) => {
         pub fn $fn_name() -> String {
@@ -96,6 +98,35 @@ gen_const!(clap_long_version_tag_const, CLAP_LONG_VERSION_TAG_CONST);
 pub(crate) const BUILD_CONST_VERSION: &str = "VERSION";
 pub(crate) const BUILD_CONST_CLAP_LONG_VERSION: &str = "CLAP_LONG_VERSION";
 
+pub(crate) fn cargo_metadata_fn(shadow: &Shadow) -> String {
+    if !shadow.map.contains_key(CARGO_METADATA) {
+        return "".to_string();
+    }
+    format!(
+        r#"
+use std::str::from_utf8;
+use shadow_rs::cargo_metadata::Metadata;
+use shadow_rs::serde_json;
+
+/// Attempts to parse the Cargo package metadata from the generated constant CARGO_METADATA.
+///
+/// Returns a `Metadata` struct containing information about the Cargo workspace,
+/// such as details about the packages and their dependencies.
+///
+/// # Return Values
+/// - `Ok(Metadata)`: Contains the parsed metadata if successful.
+/// - `Err(String)`: Returns an error message if converting the environment variable to a UTF-8 string or parsing JSON fails.
+#[allow(dead_code)]
+{}
+pub fn cargo_metadata() -> Result<Metadata, String> {{
+    let metadata_json = from_utf8(CARGO_METADATA.as_ref()).map_err(|err| format!("generate 'CARGO_METADATA' value from UTF8 error:{{}}",err))?;
+    let meta: Metadata = serde_json::from_str(metadata_json).map_err(|err| err.to_string())?;
+    Ok(meta)
+}}"#,
+        CARGO_CLIPPY_ALLOW_ALL
+    )
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/lib.rs

@@ -144,6 +144,10 @@
 //! pub const GIT_STATUS_FILE: &str = "* src/lib.rs (dirty)";
 //! ```
 //!
+#[cfg(feature = "metadata")]
+pub extern crate cargo_metadata;
+#[cfg(feature = "metadata")]
+pub extern crate serde_json;
 
 mod build;
 mod ci;
@@ -168,9 +172,9 @@ use std::io::Write;
 use std::path::Path;
 
 use crate::gen_const::{
-    clap_long_version_branch_const, clap_long_version_tag_const, clap_version_branch_const,
-    clap_version_tag_const, version_branch_const, version_tag_const, BUILD_CONST_CLAP_LONG_VERSION,
-    BUILD_CONST_VERSION,
+    cargo_metadata_fn, clap_long_version_branch_const, clap_long_version_tag_const,
+    clap_version_branch_const, clap_version_tag_const, version_branch_const, version_tag_const,
+    BUILD_CONST_CLAP_LONG_VERSION, BUILD_CONST_VERSION,
 };
 pub use err::{SdResult, ShadowError};
 
@@ -182,7 +186,7 @@ pub trait Format {
 
 const SHADOW_RS: &str = "shadow.rs";
 
-const CARGO_CLIPPY_ALLOW_ALL: &str =
+pub(crate) const CARGO_CLIPPY_ALLOW_ALL: &str =
     "#[allow(clippy::all, clippy::pedantic, clippy::restriction, clippy::nursery)]";
 
 /// Add a module with the provided name which contains the build information generated by `shadow-rs`.
@@ -231,8 +235,10 @@ pub fn new() -> SdResult<()> {
 /// membership and resolved dependencies for the current package, storing this data can result in
 /// significantly larger crate sizes. As such, the CARGO_METADATA const is disabled by default.
 ///
-/// Should you choose to retain this information, you have the option to customize a deny_const object
-/// and override the `new_deny` method parameters accordingly.
+/// Should you choose to retain this information, you have the option to customize a deny_const
+/// object and override the `new_deny` method parameters accordingly.
+///
+#[allow(clippy::all, clippy::pedantic, clippy::restriction, clippy::nursery)]
 pub fn default_deny() -> BTreeSet<ShadowConst> {
     BTreeSet::from([CARGO_METADATA])
 }
@@ -262,7 +268,9 @@ pub fn new_deny(deny_const: BTreeSet<ShadowConst>) -> SdResult<()> {
 }
 
 /// Identical to [`new`], but additionally accepts an output hook.
-/// The hook receives the output file of `shadow-rs`, and it can add additional entries to the output of `shadow-rs` by writing to this file.
+///
+/// The hook receives the output file of `shadow-rs`, and it can add additional entries to the
+/// output of `shadow-rs` by writing to this file.
 /// Note that since the output will be compiled as a Rust module, inserting invalid Rust code will lead to a compile error later on.
 ///
 /// # Example
@@ -281,6 +289,7 @@ pub fn new_deny(deny_const: BTreeSet<ShadowConst>) -> SdResult<()> {
 /// }
 ///
 /// ```
+///
 pub fn new_hook<F>(f: F) -> SdResult<()>
 where
     F: FnOnce(&File) -> SdResult<()>,
@@ -549,6 +558,8 @@ impl Shadow {
         );
         writeln!(&self.f, "{everything_define}")?;
 
+        writeln!(&self.f, "{}", cargo_metadata_fn(self))?;
+
         Ok(())
     }
 }