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node_modules/spawn-wrap/lib/mungers/shebang.js

@@ -0,0 +1,43 @@
+'use strict';
+
+const fs = require("fs")
+const path = require("path")
+const {isNode} = require("../exe-type")
+const whichOrUndefined = require("../which-or-undefined")
+
+/**
+ * Intercepts processes spawned through a script with a shebang line.
+ *
+ * @param workingDir {string} Absolute system-dependent path to the directory containing the shim files.
+ * @param options {import("../munge").InternalSpawnOptions} Original internal spawn options.
+ * @return {import("../munge").InternalSpawnOptions} Updated internal spawn options.
+ */
+function mungeShebang(workingDir, options) {
+  const resolved = whichOrUndefined(options.file)
+  if (resolved === undefined) {
+    return {...options}
+  }
+
+  const shebang = fs.readFileSync(resolved, 'utf8')
+  const match = shebang.match(/^#!([^\r\n]+)/)
+  if (!match) {
+    return {...options} // not a shebang script, probably a binary
+  }
+
+  const shebangbin = match[1].split(' ')[0]
+  const maybeNode = path.basename(shebangbin)
+  if (!isNode(maybeNode)) {
+    return {...options} // not a node shebang, leave untouched
+  }
+
+  const originalNode = shebangbin
+  const file = shebangbin
+  const args = [shebangbin, path.join(workingDir, maybeNode)]
+    .concat(resolved)
+    .concat(match[1].split(' ').slice(1))
+    .concat(options.args.slice(1))
+
+  return {...options, file, args, originalNode};
+}
+
+module.exports = mungeShebang