From 708ca82d5fe9e153c2802c6d302c20e29f874d1f Mon Sep 17 00:00:00 2001
From: figsoda <figsoda@pm.me>
Date: Thu, 12 Jan 2023 15:03:27 -0500
Subject: [PATCH] add --parse

---
 src/cli.rs             |  6 ++++++
 src/fetcher/mod.rs     | 43 ++++++++++++++++++++++++++++++++++++++++++
 src/main.rs            |  2 ++
 tests/cmd/parse.stdout |  1 +
 tests/cmd/parse.toml   |  1 +
 tests/integration.rs   |  2 +-
 6 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 tests/cmd/parse.stdout
 create mode 100644 tests/cmd/parse.toml

diff --git a/src/cli.rs b/src/cli.rs
index cac4996..6bcddab 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -33,6 +33,12 @@ pub struct Opts {
     #[arg(short, long, group = "format")]
     pub json: bool,
 
+    /// parse the url without fetching the hash, similar to --json
+    ///
+    /// note that --arg(-str) and --overwrite(-str) will be ignored silently
+    #[arg(short, long, group = "format")]
+    pub parse: bool,
+
     /// additional arguments to pass to the fetcher
     #[arg(short, long = "arg", num_args = 2, value_names = ["NAME", "EXPR"])]
     pub args: Vec<String>,
diff --git a/src/fetcher/mod.rs b/src/fetcher/mod.rs
index 4c53506..026e5d7 100644
--- a/src/fetcher/mod.rs
+++ b/src/fetcher/mod.rs
@@ -59,6 +59,13 @@ pub trait Fetcher<'a> {
         overwrites: Vec<(String, String)>,
         overwrites_str: Vec<(String, String)>,
     ) -> Result<()>;
+
+    fn to_json(
+        &'a self,
+        out: &mut impl ::std::io::Write,
+        url: &'a ::url::Url,
+        rev: Option<String>,
+    ) -> ::anyhow::Result<()>;
 }
 
 #[enum_dispatch(Fetcher)]
@@ -164,6 +171,42 @@ macro_rules! impl_fetcher {
                     overwrites_str,
                 )
             }
+
+            fn to_json(
+                &'a self,
+                out: &mut impl ::std::io::Write,
+                url: &'a ::url::Url,
+                rev: Option<String>,
+            ) -> ::anyhow::Result<()> {
+                use anyhow::Context;
+                use serde_json::{json, Value};
+
+                let values = self
+                    .get_values(url)
+                    .with_context(|| format!("failed to parse {url}"))?;
+
+                let mut fetcher_args = Value::from_iter(Self::KEYS.into_iter().zip(values));
+
+                if let Some(host) = self.host() {
+                    fetcher_args[Self::HOST_KEY] = json!(host);
+                }
+                if let Some(group) = self.group() {
+                    fetcher_args["group"] = json!(group);
+                }
+                if let Some(rev) = rev {
+                    fetcher_args["rev"] = json!(rev);
+                }
+
+                serde_json::to_writer(
+                    out,
+                    &json!({
+                        "fetcher": Self::NAME,
+                        "args": fetcher_args,
+                    }),
+                )?;
+
+                Ok(())
+            }
         }
     };
 }
diff --git a/src/main.rs b/src/main.rs
index d746d8b..d77403a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -152,6 +152,8 @@ fn main() -> Result<()> {
             opts.overwrites.into_iter().tuples().collect(),
             opts.overwrites_str.into_iter().tuples().collect(),
         )
+    } else if opts.parse {
+        fetcher.to_json(out, &opts.url, opts.rev)
     } else {
         let mut overwrites: FxHashMap<_, _> = opts.overwrites.into_iter().tuples().collect();
 
diff --git a/tests/cmd/parse.stdout b/tests/cmd/parse.stdout
new file mode 100644
index 0000000..f152586
--- /dev/null
+++ b/tests/cmd/parse.stdout
@@ -0,0 +1 @@
+{"args":{"owner":"nix-community","repo":"nurl","rev":"v0.3.0"},"fetcher":"fetchFromGitHub"}
\ No newline at end of file
diff --git a/tests/cmd/parse.toml b/tests/cmd/parse.toml
new file mode 100644
index 0000000..bab8949
--- /dev/null
+++ b/tests/cmd/parse.toml
@@ -0,0 +1 @@
+args = ["https://github.com/nix-community/nurl", "v0.3.0", "--parse"]
diff --git a/tests/integration.rs b/tests/integration.rs
index 5c51414..5eb851f 100644
--- a/tests/integration.rs
+++ b/tests/integration.rs
@@ -23,7 +23,7 @@ fn verify_outputs() {
             .strip_suffix(".stdout")
             .unwrap();
 
-        if matches!(name, "hash" | "json") {
+        if matches!(name, "hash" | "json" | "parse") {
             eprintln!("skipping {}", path.display());
             continue;
         }