1 files changed, 126 insertions, 0 deletions
diff --git a/python/mozbuild/mozbuild/nodeutil.py b/python/mozbuild/mozbuild/nodeutil.py
new file mode 100644
index 0000000000..8ec724ab89
--- /dev/null
+++ b/python/mozbuild/mozbuild/nodeutil.py
@@ -0,0 +1,126 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+import platform
+import subprocess
+from distutils.version import StrictVersion
+
+from mozboot.util import get_tools_dir
+from mozfile import which
+from six import PY3
+
+NODE_MIN_VERSION = StrictVersion("12.22.12")
+NPM_MIN_VERSION = StrictVersion("6.14.16")
+
+
+def find_node_paths():
+    """Determines the possible paths for node executables.
+
+    Returns a list of paths, which includes the build state directory.
+    """
+    mozbuild_tools_dir = get_tools_dir()
+
+    if platform.system() == "Windows":
+        mozbuild_node_path = os.path.join(mozbuild_tools_dir, "node")
+    else:
+        mozbuild_node_path = os.path.join(mozbuild_tools_dir, "node", "bin")
+
+    # We still fallback to the PATH, since on OSes that don't have toolchain
+    # artifacts available to download, Node may be coming from $PATH.
+    paths = [mozbuild_node_path] + os.environ.get("PATH").split(os.pathsep)
+
+    if platform.system() == "Windows":
+        paths += [
+            "%s\\nodejs" % os.environ.get("SystemDrive"),
+            os.path.join(os.environ.get("ProgramFiles"), "nodejs"),
+            os.path.join(os.environ.get("PROGRAMW6432"), "nodejs"),
+            os.path.join(os.environ.get("PROGRAMFILES"), "nodejs"),
+        ]
+
+    return paths
+
+
+def check_executable_version(exe, wrap_call_with_node=False):
+    """Determine the version of a Node executable by invoking it.
+
+    May raise ``subprocess.CalledProcessError`` or ``ValueError`` on failure.
+    """
+    out = None
+    # npm may be a script (Except on Windows), so we must call it with node.
+    if wrap_call_with_node and platform.system() != "Windows":
+        binary, _ = find_node_executable()
+        if binary:
+            out = (
+                subprocess.check_output(
+                    [binary, exe, "--version"], universal_newlines=PY3
+                )
+                .lstrip("v")
+                .rstrip()
+            )
+
+    # If we can't find node, or we don't need to wrap it, fallback to calling
+    # direct.
+    if not out:
+        out = (
+            subprocess.check_output([exe, "--version"], universal_newlines=PY3)
+            .lstrip("v")
+            .rstrip()
+        )
+    return StrictVersion(out)
+
+
+def find_node_executable(
+    nodejs_exe=os.environ.get("NODEJS"), min_version=NODE_MIN_VERSION
+):
+    """Find a Node executable from the mozbuild directory.
+
+    Returns a tuple containing the the path to an executable binary and a
+    version tuple. Both tuple entries will be None if a Node executable
+    could not be resolved.
+    """
+    if nodejs_exe:
+        try:
+            version = check_executable_version(nodejs_exe)
+        except (subprocess.CalledProcessError, ValueError):
+            return None, None
+
+        if version >= min_version:
+            return nodejs_exe, version.version
+
+        return None, None
+
+    # "nodejs" is first in the tuple on the assumption that it's only likely to
+    # exist on systems (probably linux distros) where there is a program in the path
+    # called "node" that does something else.
+    return find_executable("node", min_version)
+
+
+def find_npm_executable(min_version=NPM_MIN_VERSION):
+    """Find a Node executable from the mozbuild directory.
+
+    Returns a tuple containing the the path to an executable binary and a
+    version tuple. Both tuple entries will be None if a Node executable
+    could not be resolved.
+    """
+    return find_executable("npm", min_version, True)
+
+
+def find_executable(name, min_version, use_node_for_version_check=False):
+    paths = find_node_paths()
+    exe = which(name, path=paths)
+
+    if not exe:
+        return None, None
+
+    # Verify we can invoke the executable and its version is acceptable.
+    try:
+        version = check_executable_version(exe, use_node_for_version_check)
+    except (subprocess.CalledProcessError, ValueError):
+        return None, None
+
+    if version < min_version:
+        return None, None
+
+    return exe, version.version