resolc crate (#328)

- Factor the YUL crate out of `revive-solidity`.
- `revive-solidity` is in reality not a Solidity implementation but the
revive solidity compiler driver (`resolc`). By renaming we not only get
this straight but also a binary with the same name as the crate which
should be less confusing.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

crates/resolc/src/solc/soljson_compiler.rs

@@ -0,0 +1,121 @@
+//! The Solidity compiler solJson interface.
+
+use std::path::Path;
+use std::path::PathBuf;
+
+use revive_solc_json_interface::combined_json::CombinedJson;
+use revive_solc_json_interface::SolcStandardJsonInput;
+use revive_solc_json_interface::SolcStandardJsonOutput;
+
+use crate::solc::version::Version;
+use anyhow::Context;
+use std::ffi::{c_char, c_void, CStr, CString};
+
+use super::Compiler;
+
+extern "C" {
+    fn soljson_version() -> *const c_char;
+    fn soljson_compile(inputPtr: *const c_char, inputLen: usize) -> *const c_char;
+}
+
+/// The Solidity compiler.
+pub struct SoljsonCompiler;
+
+impl Compiler for SoljsonCompiler {
+    /// Compiles the Solidity `--standard-json` input into Yul IR.
+    fn standard_json(
+        &mut self,
+        mut input: SolcStandardJsonInput,
+        base_path: Option<String>,
+        include_paths: Vec<String>,
+        allow_paths: Option<String>,
+    ) -> anyhow::Result<SolcStandardJsonOutput> {
+        if !include_paths.is_empty() {
+            anyhow::bail!("configuring include paths is not supported with solJson")
+        }
+        if base_path.is_some() {
+            anyhow::bail!("configuring the base path is not supported with solJson")
+        }
+        if allow_paths.is_some() {
+            anyhow::bail!("configuring allow paths is not supported with solJson")
+        }
+
+        let version = self.version()?.validate(&include_paths)?.default;
+        input.normalize(&version);
+
+        let suppressed_warnings = input.suppressed_warnings.take().unwrap_or_default();
+
+        let input_json = serde_json::to_string(&input).expect("Always valid");
+        let out = Self::compile_standard_json(input_json)?;
+        let mut output: SolcStandardJsonOutput =
+            revive_common::deserialize_from_slice(out.as_bytes()).map_err(|error| {
+                anyhow::anyhow!(
+                    "Soljson output parsing error: {}\n{}",
+                    error,
+                    revive_common::deserialize_from_slice::<serde_json::Value>(out.as_bytes())
+                        .map(|json| serde_json::to_string_pretty(&json).expect("Always valid"))
+                        .unwrap_or_else(|_| String::from_utf8_lossy(out.as_bytes()).to_string()),
+                )
+            })?;
+        output.preprocess_ast(suppressed_warnings.as_slice())?;
+
+        Ok(output)
+    }
+
+    fn combined_json(
+        &self,
+        _paths: &[PathBuf],
+        _combined_json_argument: &str,
+    ) -> anyhow::Result<CombinedJson> {
+        unimplemented!();
+    }
+
+    fn validate_yul(&self, _path: &Path) -> anyhow::Result<()> {
+        unimplemented!();
+    }
+
+    fn version(&mut self) -> anyhow::Result<Version> {
+        let version = Self::get_soljson_version()?;
+        let long = version.clone();
+        let default: semver::Version = version
+            .split('+')
+            .next()
+            .ok_or_else(|| anyhow::anyhow!("Soljson version parsing: metadata dropping"))?
+            .parse()
+            .map_err(|error| anyhow::anyhow!("Soljson version parsing: {}", error))?;
+        let l2_revision: Option<semver::Version> = version
+            .split('-')
+            .nth(1)
+            .and_then(|version| version.parse().ok());
+        Ok(Version::new(long, default, l2_revision))
+    }
+}
+
+impl SoljsonCompiler {
+    fn get_soljson_version() -> anyhow::Result<String> {
+        unsafe {
+            let version_ptr = soljson_version();
+            let version = CStr::from_ptr(version_ptr)
+                .to_str()
+                .with_context(|| "Failed to convert C string to Rust string")
+                .map(str::to_owned);
+            libc::free(version_ptr as *mut c_void);
+            Ok(version?)
+        }
+    }
+
+    fn compile_standard_json(input: String) -> anyhow::Result<String> {
+        let c_input = CString::new(input).unwrap();
+        let c_input_len = c_input.as_bytes().len();
+
+        unsafe {
+            let output_ptr = soljson_compile(c_input.as_ptr(), c_input_len);
+            let output_json = CStr::from_ptr(output_ptr)
+                .to_str()
+                .with_context(|| "Failed to convert C string to Rust string")
+                .map(str::to_owned);
+            libc::free(output_ptr as *mut c_void);
+            Ok(output_json?)
+        }
+    }
+}