1 files changed, 95 insertions, 0 deletions
diff --git a/build/rust/mozbuild/generate_buildconfig.py b/build/rust/mozbuild/generate_buildconfig.py
new file mode 100644
index 0000000000..2252276319
--- /dev/null
+++ b/build/rust/mozbuild/generate_buildconfig.py
@@ -0,0 +1,95 @@
+# 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 string
+import textwrap
+
+import buildconfig
+
+
+def generate_bool(name):
+    value = buildconfig.substs.get(name)
+    return f"pub const {name}: bool = {'true' if value else 'false'};\n"
+
+
+def escape_rust_string(value):
+    """escape the string into a Rust literal"""
+    # This could be more generous, but we're only escaping paths with it.
+    unescaped = string.ascii_letters + string.digits + "/$+-_~ "
+    result = ""
+    for ch in str(value):
+        if ch in unescaped:
+            result += ch
+        elif ch == "\r":
+            result += "\\r"
+        elif ch == "\n":
+            result += "\\n"
+        elif ch == "\\":
+            result += "\\\\"
+        elif ch == '"':
+            result += '\\"'
+        else:
+            result += "\\u{%x}" % ord(ch)
+    return '"%s"' % result
+
+
+def generate(output):
+    # Write out a macro which can be used within `include!`-like methods to
+    # reference the topobjdir.
+    output.write(
+        textwrap.dedent(
+            f"""
+            /// Macro used to name a path in the objdir for use with macros like `include!`
+            #[macro_export]
+            macro_rules! objdir_path {{
+                ($path:literal) => {{
+                    concat!({escape_rust_string(buildconfig.topobjdir + "/")}, $path)
+                }}
+            }}
+
+            /// Macro used to name a path in the srcdir for use with macros like `include!`
+            #[macro_export]
+            macro_rules! srcdir_path {{
+                ($path:literal) => {{
+                    concat!({escape_rust_string(buildconfig.topsrcdir + "/")}, $path)
+                }}
+            }}
+
+            /// The objdir path for use in build scripts
+            pub const TOPOBJDIR: &str = {escape_rust_string(buildconfig.topobjdir)};
+            /// The srcdir path for use in build scripts
+            pub const TOPSRCDIR: &str = {escape_rust_string(buildconfig.topsrcdir)};
+
+            """
+        )
+    )
+
+    windows_rs_dir = buildconfig.substs.get("MOZ_WINDOWS_RS_DIR")
+    if windows_rs_dir:
+        output.write(
+            textwrap.dedent(
+                f"""
+                /// Macro used to name a path in the srcdir for use with macros like `include!`
+                #[macro_export]
+                macro_rules! windows_rs_path {{
+                    ($path:literal) => {{
+                        concat!({escape_rust_string(windows_rs_dir + "/")}, $path)
+                    }}
+                }}
+
+                /// The path to the windows-rs crate, for use in build scripts
+                pub const WINDOWS_RS_DIR: &str = {escape_rust_string(windows_rs_dir)};
+
+                """
+            )
+        )
+
+    # Finally, write out some useful booleans from the buildconfig.
+    output.write(generate_bool("MOZ_FOLD_LIBS"))
+    output.write(generate_bool("NIGHTLY_BUILD"))
+    output.write(generate_bool("RELEASE_OR_BETA"))
+    output.write(generate_bool("EARLY_BETA_OR_EARLIER"))
+    output.write(generate_bool("MOZ_DEV_EDITION"))
+    output.write(generate_bool("MOZ_ESR"))
+    output.write(generate_bool("MOZ_DIAGNOSTIC_ASSERT_ENABLED"))