From c002256dfda95647473db2c020978f56d06fdcce Mon Sep 17 00:00:00 2001
From: data-pup <kevinmartinucr@gmail.com>
Date: Mon, 18 Jun 2018 20:01:51 -0400
Subject: [PATCH] Solves #146. Check locally installed wasm-bindgen dependency.

---
 src/bindgen.rs      | 36 +++++++++++++++++++++++++++++++++---
 src/command/init.rs | 22 +++++++++++++++++++---
 src/manifest.rs     |  7 +++++++
 3 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/src/bindgen.rs b/src/bindgen.rs
index 7405dde3b..0a6b50622 100644
--- a/src/bindgen.rs
+++ b/src/bindgen.rs
@@ -1,16 +1,46 @@
 use emoji;
 use error::Error;
 use progressbar::Step;
-use std::process::Command;
+use std::{path, process::Command};
 use PBAR;
 
-pub fn cargo_install_wasm_bindgen(step: &Step) -> Result<(), Error> {
+static LOCAL_BINDGEN_PATH: &str = "bin/wasm-bindgen";
+
+fn wasm_bindgen_exists_locally(crate_path: &str) -> bool {
+    let path_str = format!("{}/{}", crate_path, LOCAL_BINDGEN_PATH);
+    let bindgen_abs_path = path::Path::new(&path_str);
+    bindgen_abs_path.is_file()
+}
+
+pub fn wasm_bindgen_version_check(crate_path: &str, dep_version: &str) -> Result<bool, Error> {
+    if !wasm_bindgen_exists_locally(crate_path) {
+        return Ok(false);
+    }
+
+    let output = Command::new(LOCAL_BINDGEN_PATH).arg("--version").output()?;
+    if output.status.success() {
+        let stdout = String::from_utf8_lossy(&output.stdout);
+        let installed_version = stdout.trim();
+        Ok(dep_version == installed_version)
+    } else {
+        let message = "Could not find version of local wasm-bindgen".to_string();
+        let stderr = String::from_utf8_lossy(&output.stderr).to_string();
+        let e = Error::Cli { message, stderr };
+        Err(e)
+    }
+}
+
+pub fn cargo_install_wasm_bindgen(path: &str, version: &str, step: &Step) -> Result<(), Error> {
     let msg = format!("{}Installing WASM-bindgen...", emoji::DOWN_ARROW);
     PBAR.step(step, &msg)?;
     let output = Command::new("cargo")
         .arg("install")
-        .arg("wasm-bindgen-cli")
         .arg("--force")
+        .arg("wasm-bindgen-cli")
+        .arg("--version")
+        .arg(version)
+        .arg("--root")
+        .arg(path)
         .output()?;
     if !output.status.success() {
         let s = String::from_utf8_lossy(&output.stderr);
diff --git a/src/command/init.rs b/src/command/init.rs
index c409a8659..f2211b0b4 100644
--- a/src/command/init.rs
+++ b/src/command/init.rs
@@ -188,9 +188,25 @@ impl Init {
         step: &Step,
         log: &Logger,
     ) -> result::Result<(), Error> {
-        info!(&log, "Installing wasm-bindgen-cli...");
-        bindgen::cargo_install_wasm_bindgen(step)?;
-        info!(&log, "Installing wasm-bindgen-cli was successful.");
+        let bindgen_version =
+            manifest::get_wasm_bindgen_version(&self.crate_path)?.ok_or(Error::CrateConfig {
+                message: "Unexpected error while parsing wasm-bindgen dependency version"
+                    .to_string(),
+            })?;
+
+        if bindgen_version.is_empty() {
+            let e = Error::CrateConfig {
+                message: "wasm-bindgen version dependency was empty".to_string(),
+            };
+            return Err(e);
+        }
+
+        info!(&log, "Checking WASM-bindgen version...");
+        if !bindgen::wasm_bindgen_version_check(&self.crate_path, &bindgen_version)? {
+            info!(&log, "Installing wasm-bindgen-cli...");
+            bindgen::cargo_install_wasm_bindgen(&self.crate_path, &bindgen_version, step)?;
+            info!(&log, "Installing wasm-bindgen-cli was successful.");
+        }
 
         info!(&log, "Getting the crate name from the manifest...");
         self.crate_name = Some(manifest::get_crate_name(&self.crate_path)?);
diff --git a/src/manifest.rs b/src/manifest.rs
index 22c95c4bb..718832c99 100644
--- a/src/manifest.rs
+++ b/src/manifest.rs
@@ -148,6 +148,13 @@ pub fn get_crate_name(path: &str) -> Result<String, Error> {
     Ok(read_cargo_toml(path)?.package.name)
 }
 
+pub fn get_wasm_bindgen_version(path: &str) -> Result<Option<String>, Error> {
+    let version: Option<String> = read_cargo_toml(path)?
+        .dependencies
+        .and_then(|deps| deps.wasm_bindgen);
+    Ok(version)
+}
+
 pub fn check_crate_config(path: &str, step: &Step) -> Result<(), Error> {
     let msg = format!("{}Checking crate configuration...", emoji::WRENCH);
     PBAR.step(&step, &msg)?;