[SCons] Move the GodotCPP build to its own tool.

(cherry picked from commit f8b4f60cb9177a6238adfbdfdfc673d72b3878a5)

SConstruct

@@ -7,54 +7,9 @@ import subprocess
 from binding_generator import scons_generate_bindings, scons_emit_files
 from SCons.Errors import UserError
 
-EnsureSConsVersion(4, 0)
-
-
-def add_sources(sources, dir, extension):
-    for f in os.listdir(dir):
-        if f.endswith("." + extension):
-            sources.append(dir + "/" + f)
-
-
-def normalize_path(val):
-    return val if os.path.isabs(val) else os.path.join(env.Dir("#").abspath, val)
-
-
-def validate_file(key, val, env):
-    if not os.path.isfile(normalize_path(val)):
-        raise UserError("'%s' is not a file: %s" % (key, val))
-
-
-def validate_dir(key, val, env):
-    if not os.path.isdir(normalize_path(val)):
-        raise UserError("'%s' is not a directory: %s" % (key, val))
-
-
-def validate_parent_dir(key, val, env):
-    if not os.path.isdir(normalize_path(os.path.dirname(val))):
-        raise UserError("'%s' is not a directory: %s" % (key, os.path.dirname(val)))
-
-
-def get_gdextension_dir(env):
-    return normalize_path(env.get("gdextension_dir", env.Dir("gdextension").abspath))
-
-
-def get_api_file(env):
-    return normalize_path(env.get("custom_api_file", os.path.join(get_gdextension_dir(env), "extension_api.json")))
 
+EnsureSConsVersion(4, 0)
 
-# Try to detect the host platform automatically.
-# This is used if no `platform` argument is passed
-if sys.platform.startswith("linux"):
-    default_platform = "linux"
-elif sys.platform == "darwin":
-    default_platform = "macos"
-elif sys.platform == "win32" or sys.platform == "msys":
-    default_platform = "windows"
-elif ARGUMENTS.get("platform", ""):
-    default_platform = ARGUMENTS.get("platform")
-else:
-    raise ValueError("Could not detect platform automatically, please specify with platform=<platform>")
 
 try:
     Import("env")
@@ -65,24 +20,6 @@ except:
 
 env.PrependENVPath("PATH", os.getenv("PATH"))
 
-# Default num_jobs to local cpu count if not user specified.
-# SCons has a peculiarity where user-specified options won't be overridden
-# by SetOption, so we can rely on this to know if we should use our default.
-initial_num_jobs = env.GetOption("num_jobs")
-altered_num_jobs = initial_num_jobs + 1
-env.SetOption("num_jobs", altered_num_jobs)
-if env.GetOption("num_jobs") == altered_num_jobs:
-    cpu_count = os.cpu_count()
-    if cpu_count is None:
-        print("Couldn't auto-detect CPU count to configure build parallelism. Specify it with the -j argument.")
-    else:
-        safer_cpu_count = cpu_count if cpu_count <= 4 else cpu_count - 1
-        print(
-            "Auto-detected %d CPU cores available for build parallelism. Using %d cores by default. You can override it with the -j argument."
-            % (cpu_count, safer_cpu_count)
-        )
-        env.SetOption("num_jobs", safer_cpu_count)
-
 # Custom options and profile flags.
 customs = ["custom.py"]
 profile = ARGUMENTS.get("profile", "")
@@ -92,159 +29,11 @@ if profile:
     elif os.path.isfile(profile + ".py"):
         customs.append(profile + ".py")
 opts = Variables(customs, ARGUMENTS)
-
-platforms = ("linux", "macos", "windows", "android", "ios", "javascript")
-opts.Add(
-    EnumVariable(
-        key="platform",
-        help="Target platform",
-        default=env.get("platform", default_platform),
-        allowed_values=platforms,
-        ignorecase=2,
-    )
-)
-
-# Editor and template_debug are compatible (i.e. you can use the same binary for Godot editor builds and Godot debug templates).
-# Godot release templates are only compatible with "template_release" builds.
-# For this reason, we default to template_debug builds, unlike Godot which defaults to editor builds.
-opts.Add(
-    EnumVariable(
-        key="target",
-        help="Compilation target",
-        default=env.get("target", "template_debug"),
-        allowed_values=("editor", "template_release", "template_debug"),
-    )
-)
-opts.Add(
-    PathVariable(
-        key="gdextension_dir",
-        help="Path to a custom directory containing GDExtension interface header and API JSON file",
-        default=env.get("gdextension_dir", None),
-        validator=validate_dir,
-    )
-)
-opts.Add(
-    PathVariable(
-        key="custom_api_file",
-        help="Path to a custom GDExtension API JSON file (takes precedence over `gdextension_dir`)",
-        default=env.get("custom_api_file", None),
-        validator=validate_file,
-    )
-)
-opts.Add(
-    BoolVariable(
-        key="generate_bindings",
-        help="Force GDExtension API bindings generation. Auto-detected by default.",
-        default=env.get("generate_bindings", False),
-    )
-)
-opts.Add(
-    BoolVariable(
-        key="generate_template_get_node",
-        help="Generate a template version of the Node class's get_node.",
-        default=env.get("generate_template_get_node", True),
-    )
-)
-
-opts.Add(BoolVariable(key="build_library", help="Build the godot-cpp library.", default=env.get("build_library", True)))
-opts.Add(
-    EnumVariable(
-        key="precision",
-        help="Set the floating-point precision level",
-        default=env.get("precision", "single"),
-        allowed_values=("single", "double"),
-    )
-)
-
-# compiledb
-opts.Add(
-    BoolVariable(
-        key="compiledb",
-        help="Generate compilation DB (`compile_commands.json`) for external tools",
-        default=env.get("compiledb", False),
-    )
-)
-opts.Add(
-    PathVariable(
-        key="compiledb_file",
-        help="Path to a custom `compile_commands.json` file",
-        default=env.get("compiledb_file", "compile_commands.json"),
-        validator=validate_parent_dir,
-    )
-)
-
-# Add platform options
-tools = {}
-for pl in platforms:
-    tool = Tool(pl, toolpath=["tools"])
-    if hasattr(tool, "options"):
-        tool.options(opts)
-    tools[pl] = tool
-
-# CPU architecture options.
-architecture_array = ["", "universal", "x86_32", "x86_64", "arm32", "arm64", "rv64", "ppc32", "ppc64", "wasm32"]
-architecture_aliases = {
-    "x64": "x86_64",
-    "amd64": "x86_64",
-    "armv7": "arm32",
-    "armv8": "arm64",
-    "arm64v8": "arm64",
-    "aarch64": "arm64",
-    "rv": "rv64",
-    "riscv": "rv64",
-    "riscv64": "rv64",
-    "ppcle": "ppc32",
-    "ppc": "ppc32",
-    "ppc64le": "ppc64",
-}
-opts.Add(
-    EnumVariable(
-        key="arch",
-        help="CPU architecture",
-        default=env.get("arch", ""),
-        allowed_values=architecture_array,
-        map=architecture_aliases,
-    )
-)
-
-# Targets flags tool (optimizations, debug symbols)
-target_tool = Tool("targets", toolpath=["tools"])
-target_tool.options(opts)
-
+cpp_tool = Tool("godotcpp", toolpath=["tools"])
+cpp_tool.options(opts, env)
 opts.Update(env)
-Help(opts.GenerateHelpText(env))
-
-# Process CPU architecture argument.
-if env["arch"] == "":
-    # No architecture specified. Default to arm64 if building for Android,
-    # universal if building for macOS or iOS, wasm32 if building for web,
-    # otherwise default to the host architecture.
-    if env["platform"] in ["macos", "ios"]:
-        env["arch"] = "universal"
-    elif env["platform"] == "android":
-        env["arch"] = "arm64"
-    elif env["platform"] == "javascript":
-        env["arch"] = "wasm32"
-    else:
-        host_machine = platform.machine().lower()
-        if host_machine in architecture_array:
-            env["arch"] = host_machine
-        elif host_machine in architecture_aliases.keys():
-            env["arch"] = architecture_aliases[host_machine]
-        elif "86" in host_machine:
-            # Catches x86, i386, i486, i586, i686, etc.
-            env["arch"] = "x86_32"
-        else:
-            print("Unsupported CPU architecture: " + host_machine)
-            Exit()
 
-tool = Tool(env["platform"], toolpath=["tools"])
-
-if tool is None or not tool.exists(env):
-    raise ValueError("Required toolchain not found for platform " + env["platform"])
-
-tool.generate(env)
-target_tool.generate(env)
+Help(opts.GenerateHelpText(env))
 
 # Detect and print a warning listing unknown SCons variables to ease troubleshooting.
 unknown = opts.UnknownVariables()
@@ -253,71 +42,12 @@ if unknown:
     for item in unknown.items():
         print("    " + item[0] + "=" + item[1])
 
-print("Building for architecture " + env["arch"] + " on platform " + env["platform"])
-
-# Require C++17
-if env.get("is_msvc", False):
-    env.Append(CXXFLAGS=["/std:c++17"])
-else:
-    env.Append(CXXFLAGS=["-std=c++17"])
-
-if env["precision"] == "double":
-    env.Append(CPPDEFINES=["REAL_T_IS_DOUBLE"])
-
-# compile_commands.json
-if env.get("compiledb", False):
-    env.Tool("compilation_db")
-    env.Alias("compiledb", env.CompilationDatabase(normalize_path(env["compiledb_file"])))
-
-# Generate bindings
-env.Append(BUILDERS={"GenerateBindings": Builder(action=scons_generate_bindings, emitter=scons_emit_files)})
-
-bindings = env.GenerateBindings(
-    env.Dir("."),
-    [get_api_file(env), os.path.join(get_gdextension_dir(env), "gdextension_interface.h"), "binding_generator.py"],
-)
-
 scons_cache_path = os.environ.get("SCONS_CACHE")
 if scons_cache_path is not None:
     CacheDir(scons_cache_path)
     Decider("MD5")
 
-# Forces bindings regeneration.
-if env["generate_bindings"]:
-    AlwaysBuild(bindings)
-    NoCache(bindings)
-
-# Includes
-env.Append(CPPPATH=[[env.Dir(d) for d in [get_gdextension_dir(env), "include", os.path.join("gen", "include")]]])
-
-# Sources to compile
-sources = []
-add_sources(sources, "src", "cpp")
-add_sources(sources, "src/classes", "cpp")
-add_sources(sources, "src/core", "cpp")
-add_sources(sources, "src/variant", "cpp")
-sources.extend([f for f in bindings if str(f).endswith(".cpp")])
-
-suffix = ".{}.{}".format(env["platform"], env["target"])
-if env.dev_build:
-    suffix += ".dev"
-if env["precision"] == "double":
-    suffix += ".double"
-suffix += "." + env["arch"]
-if env["ios_simulator"]:
-    suffix += ".simulator"
-
-# Expose it when included from another project
-env["suffix"] = suffix
-
-library = None
-env["OBJSUFFIX"] = suffix + env["OBJSUFFIX"]
-library_name = "libgodot-cpp{}{}".format(suffix, env["LIBSUFFIX"])
-
-if env["build_library"]:
-    library = env.StaticLibrary(target=env.File("bin/%s" % library_name), source=sources)
-    Default(library)
+cpp_tool.generate(env)
+library = env.GodotCPP()
 
-env.Append(LIBPATH=[env.Dir("bin")])
-env.Append(LIBS=library_name)
 Return("env")

tools/godotcpp.py

@@ -0,0 +1,309 @@
+import os, sys, platform
+
+from SCons.Variables import EnumVariable, PathVariable, BoolVariable
+from SCons.Tool import Tool
+from SCons.Builder import Builder
+
+from binding_generator import scons_generate_bindings, scons_emit_files
+
+
+def add_sources(sources, dir, extension):
+    for f in os.listdir(dir):
+        if f.endswith("." + extension):
+            sources.append(dir + "/" + f)
+
+
+def normalize_path(val, env):
+    return val if os.path.isabs(val) else os.path.join(env.Dir("#").abspath, val)
+
+
+def validate_file(key, val, env):
+    if not os.path.isfile(normalize_path(val, env)):
+        raise UserError("'%s' is not a file: %s" % (key, val))
+
+
+def validate_dir(key, val, env):
+    if not os.path.isdir(normalize_path(val, env)):
+        raise UserError("'%s' is not a directory: %s" % (key, val))
+
+
+def validate_parent_dir(key, val, env):
+    if not os.path.isdir(normalize_path(os.path.dirname(val), env)):
+        raise UserError("'%s' is not a directory: %s" % (key, os.path.dirname(val)))
+
+
+platforms = ("linux", "macos", "windows", "android", "ios", "javascript")
+
+# CPU architecture options.
+architecture_array = [
+    "",
+    "universal",
+    "x86_32",
+    "x86_64",
+    "arm32",
+    "arm64",
+    "rv64",
+    "ppc32",
+    "ppc64",
+    "wasm32",
+]
+architecture_aliases = {
+    "x64": "x86_64",
+    "amd64": "x86_64",
+    "armv7": "arm32",
+    "armv8": "arm64",
+    "arm64v8": "arm64",
+    "aarch64": "arm64",
+    "rv": "rv64",
+    "riscv": "rv64",
+    "riscv64": "rv64",
+    "ppcle": "ppc32",
+    "ppc": "ppc32",
+    "ppc64le": "ppc64",
+}
+
+
+def exists(env):
+    return True
+
+
+def options(opts, env):
+    # Try to detect the host platform automatically.
+    # This is used if no `platform` argument is passed
+    if sys.platform.startswith("linux"):
+        default_platform = "linux"
+    elif sys.platform == "darwin":
+        default_platform = "macos"
+    elif sys.platform == "win32" or sys.platform == "msys":
+        default_platform = "windows"
+    elif ARGUMENTS.get("platform", ""):
+        default_platform = ARGUMENTS.get("platform")
+    else:
+        raise ValueError("Could not detect platform automatically, please specify with platform=<platform>")
+
+    opts.Add(
+        EnumVariable(
+            key="platform",
+            help="Target platform",
+            default=env.get("platform", default_platform),
+            allowed_values=platforms,
+            ignorecase=2,
+        )
+    )
+
+    # Editor and template_debug are compatible (i.e. you can use the same binary for Godot editor builds and Godot debug templates).
+    # Godot release templates are only compatible with "template_release" builds.
+    # For this reason, we default to template_debug builds, unlike Godot which defaults to editor builds.
+    opts.Add(
+        EnumVariable(
+            key="target",
+            help="Compilation target",
+            default=env.get("target", "template_debug"),
+            allowed_values=("editor", "template_release", "template_debug"),
+        )
+    )
+    opts.Add(
+        PathVariable(
+            key="gdextension_dir",
+            help="Path to a custom directory containing GDExtension interface header and API JSON file",
+            default=env.get("gdextension_dir", None),
+            validator=validate_dir,
+        )
+    )
+    opts.Add(
+        PathVariable(
+            key="custom_api_file",
+            help="Path to a custom GDExtension API JSON file (takes precedence over `gdextension_dir`)",
+            default=env.get("custom_api_file", None),
+            validator=validate_file,
+        )
+    )
+    opts.Add(
+        BoolVariable(
+            key="generate_bindings",
+            help="Force GDExtension API bindings generation. Auto-detected by default.",
+            default=env.get("generate_bindings", False),
+        )
+    )
+    opts.Add(
+        BoolVariable(
+            key="generate_template_get_node",
+            help="Generate a template version of the Node class's get_node.",
+            default=env.get("generate_template_get_node", True),
+        )
+    )
+    opts.Add(
+        BoolVariable(
+            key="build_library",
+            help="Build the godot-cpp library.",
+            default=env.get("build_library", True),
+        )
+    )
+    opts.Add(
+        EnumVariable(
+            key="precision",
+            help="Set the floating-point precision level",
+            default=env.get("precision", "single"),
+            allowed_values=("single", "double"),
+        )
+    )
+    opts.Add(
+        EnumVariable(
+            key="arch",
+            help="CPU architecture",
+            default=env.get("arch", ""),
+            allowed_values=architecture_array,
+            map=architecture_aliases,
+        )
+    )
+
+    # compiledb
+    opts.Add(
+        BoolVariable(
+            key="compiledb",
+            help="Generate compilation DB (`compile_commands.json`) for external tools",
+            default=env.get("compiledb", False),
+        )
+    )
+    opts.Add(
+        PathVariable(
+            key="compiledb_file",
+            help="Path to a custom `compile_commands.json` file",
+            default=env.get("compiledb_file", "compile_commands.json"),
+            validator=validate_parent_dir,
+        )
+    )
+
+    # Add platform options
+    for pl in platforms:
+        tool = Tool(pl, toolpath=["tools"])
+        if hasattr(tool, "options"):
+            tool.options(opts)
+
+    # Targets flags tool (optimizations, debug symbols)
+    target_tool = Tool("targets", toolpath=["tools"])
+    target_tool.options(opts)
+
+
+def generate(env):
+    # Default num_jobs to local cpu count if not user specified.
+    # SCons has a peculiarity where user-specified options won't be overridden
+    # by SetOption, so we can rely on this to know if we should use our default.
+    initial_num_jobs = env.GetOption("num_jobs")
+    altered_num_jobs = initial_num_jobs + 1
+    env.SetOption("num_jobs", altered_num_jobs)
+    if env.GetOption("num_jobs") == altered_num_jobs:
+        cpu_count = os.cpu_count()
+        if cpu_count is None:
+            print("Couldn't auto-detect CPU count to configure build parallelism. Specify it with the -j argument.")
+        else:
+            safer_cpu_count = cpu_count if cpu_count <= 4 else cpu_count - 1
+            print(
+                "Auto-detected %d CPU cores available for build parallelism. Using %d cores by default. You can override it with the -j argument."
+                % (cpu_count, safer_cpu_count)
+            )
+            env.SetOption("num_jobs", safer_cpu_count)
+
+    # Process CPU architecture argument.
+    if env["arch"] == "":
+        # No architecture specified. Default to arm64 if building for Android,
+        # universal if building for macOS or iOS, wasm32 if building for web,
+        # otherwise default to the host architecture.
+        if env["platform"] in ["macos", "ios"]:
+            env["arch"] = "universal"
+        elif env["platform"] == "android":
+            env["arch"] = "arm64"
+        elif env["platform"] == "javascript":
+            env["arch"] = "wasm32"
+        else:
+            host_machine = platform.machine().lower()
+            if host_machine in architecture_array:
+                env["arch"] = host_machine
+            elif host_machine in architecture_aliases.keys():
+                env["arch"] = architecture_aliases[host_machine]
+            elif "86" in host_machine:
+                # Catches x86, i386, i486, i586, i686, etc.
+                env["arch"] = "x86_32"
+            else:
+                print("Unsupported CPU architecture: " + host_machine)
+                Exit()
+
+    print("Building for architecture " + env["arch"] + " on platform " + env["platform"])
+
+    tool = Tool(env["platform"], toolpath=["tools"])
+
+    if tool is None or not tool.exists(env):
+        raise ValueError("Required toolchain not found for platform " + env["platform"])
+
+    tool.generate(env)
+    target_tool = Tool("targets", toolpath=["tools"])
+    target_tool.generate(env)
+
+    # Require C++17
+    if env.get("is_msvc", False):
+        env.Append(CXXFLAGS=["/std:c++17"])
+    else:
+        env.Append(CXXFLAGS=["-std=c++17"])
+
+    if env["precision"] == "double":
+        env.Append(CPPDEFINES=["REAL_T_IS_DOUBLE"])
+
+    # Suffix
+    suffix = ".{}.{}".format(env["platform"], env["target"])
+    if env.dev_build:
+        suffix += ".dev"
+    if env["precision"] == "double":
+        suffix += ".double"
+    suffix += "." + env["arch"]
+    if env["ios_simulator"]:
+        suffix += ".simulator"
+
+    env["suffix"] = suffix  # Exposed when included from another project
+    env["OBJSUFFIX"] = suffix + env["OBJSUFFIX"]
+
+    # compile_commands.json
+    if env.get("compiledb", False):
+        env.Tool("compilation_db")
+        env.Alias("compiledb", env.CompilationDatabase(normalize_path(env["compiledb_file"], env)))
+
+    # Builders
+    env.Append(BUILDERS={"GodotCPPBindings": Builder(action=scons_generate_bindings, emitter=scons_emit_files)})
+    env.AddMethod(_godot_cpp, "GodotCPP")
+
+
+def _godot_cpp(env):
+    api_file = normalize_path(env.get("custom_api_file", env.File("gdextension/extension_api.json").abspath), env)
+    extension_dir = normalize_path(env.get("gdextension_dir", env.Dir("gdextension").abspath), env)
+    bindings = env.GodotCPPBindings(
+        env.Dir("."),
+        [
+            api_file,
+            os.path.join(extension_dir, "gdextension_interface.h"),
+            "binding_generator.py",
+        ],
+    )
+    # Forces bindings regeneration.
+    if env["generate_bindings"]:
+        AlwaysBuild(bindings)
+        NoCache(bindings)
+
+    # Sources to compile
+    sources = []
+    add_sources(sources, "src", "cpp")
+    add_sources(sources, "src/classes", "cpp")
+    add_sources(sources, "src/core", "cpp")
+    add_sources(sources, "src/variant", "cpp")
+    sources.extend([f for f in bindings if str(f).endswith(".cpp")])
+
+    # Includes
+    env.AppendUnique(CPPPATH=[env.Dir(d) for d in [extension_dir, "include", "gen/include"]])
+
+    library = None
+    library_name = "libgodot-cpp" + env["suffix"] + env["LIBSUFFIX"]
+
+    if env["build_library"]:
+        library = env.StaticLibrary(target=env.File("bin/%s" % library_name), source=sources)
+        env.Default(library)
+
+    env.AppendUnique(LIBS=[env.File("bin/%s" % library_name)])
+    return library