# Copyright (c) 2013 Google Inc. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Utility functions shared amongst the Windows generators."""

import copy
import os

# A dictionary mapping supported target types to extensions.
TARGET_TYPE_EXT = {
    "executable": "exe",
    "loadable_module": "dll",
    "shared_library": "dll",
    "static_library": "lib",
    "windows_driver": "sys",
}


def _GetLargePdbShimCcPath():
    """Returns the path of the large_pdb_shim.cc file."""
    this_dir = os.path.abspath(os.path.dirname(__file__))
    src_dir = os.path.abspath(os.path.join(this_dir, "..", ".."))
    win_data_dir = os.path.join(src_dir, "data", "win")
    large_pdb_shim_cc = os.path.join(win_data_dir, "large-pdb-shim.cc")
    return large_pdb_shim_cc


def _DeepCopySomeKeys(in_dict, keys):
    """Performs a partial deep-copy on |in_dict|, only copying the keys in |keys|.

    Arguments:
      in_dict: The dictionary to copy.
      keys: The keys to be copied. If a key is in this list and doesn't exist in
          |in_dict| this is not an error.
    Returns:
      The partially deep-copied dictionary.
    """
    d = {}
    for key in keys:
        if key not in in_dict:
            continue
        d[key] = copy.deepcopy(in_dict[key])
    return d


def _SuffixName(name, suffix):
    """Add a suffix to the end of a target.

    Arguments:
      name: name of the target (foo#target)
      suffix: the suffix to be added
    Returns:
      Target name with suffix added (foo_suffix#target)
    """
    parts = name.rsplit("#", 1)
    parts[0] = f"{parts[0]}_{suffix}"
    return "#".join(parts)


def _ShardName(name, number):
    """Add a shard number to the end of a target.

    Arguments:
      name: name of the target (foo#target)
      number: shard number
    Returns:
      Target name with shard added (foo_1#target)
    """
    return _SuffixName(name, str(number))


def ShardTargets(target_list, target_dicts):
    """Shard some targets apart to work around the linkers limits.

    Arguments:
      target_list: List of target pairs: 'base/base.gyp:base'.
      target_dicts: Dict of target properties keyed on target pair.
    Returns:
      Tuple of the new sharded versions of the inputs.
    """
    # Gather the targets to shard, and how many pieces.
    targets_to_shard = {}
    for t in target_dicts:
        shards = int(target_dicts[t].get("msvs_shard", 0))
        if shards:
            targets_to_shard[t] = shards
    # Shard target_list.
    new_target_list = []
    for t in target_list:
        if t in targets_to_shard:
            for i in range(targets_to_shard[t]):
                new_target_list.append(_ShardName(t, i))
        else:
            new_target_list.append(t)
    # Shard target_dict.
    new_target_dicts = {}
    for t in target_dicts:
        if t in targets_to_shard:
            for i in range(targets_to_shard[t]):
                name = _ShardName(t, i)
                new_target_dicts[name] = copy.copy(target_dicts[t])
                new_target_dicts[name]["target_name"] = _ShardName(
                    new_target_dicts[name]["target_name"], i
                )
                sources = new_target_dicts[name].get("sources", [])
                new_sources = []
                for pos in range(i, len(sources), targets_to_shard[t]):
                    new_sources.append(sources[pos])
                new_target_dicts[name]["sources"] = new_sources
        else:
            new_target_dicts[t] = target_dicts[t]
    # Shard dependencies.
    for t in sorted(new_target_dicts):
        for deptype in ("dependencies", "dependencies_original"):
            dependencies = copy.copy(new_target_dicts[t].get(deptype, []))
            new_dependencies = []
            for d in dependencies:
                if d in targets_to_shard:
                    for i in range(targets_to_shard[d]):
                        new_dependencies.append(_ShardName(d, i))
                else:
                    new_dependencies.append(d)
            new_target_dicts[t][deptype] = new_dependencies

    return (new_target_list, new_target_dicts)


def _GetPdbPath(target_dict, config_name, vars):
    """Returns the path to the PDB file that will be generated by a given
    configuration.

    The lookup proceeds as follows:
      - Look for an explicit path in the VCLinkerTool configuration block.
      - Look for an 'msvs_large_pdb_path' variable.
      - Use '<(PRODUCT_DIR)/<(product_name).(exe|dll).pdb' if 'product_name' is
        specified.
      - Use '<(PRODUCT_DIR)/<(target_name).(exe|dll).pdb'.

    Arguments:
      target_dict: The target dictionary to be searched.
      config_name: The name of the configuration of interest.
      vars: A dictionary of common GYP variables with generator-specific values.
    Returns:
      The path of the corresponding PDB file.
    """
    config = target_dict["configurations"][config_name]
    msvs = config.setdefault("msvs_settings", {})

    linker = msvs.get("VCLinkerTool", {})

    pdb_path = linker.get("ProgramDatabaseFile")
    if pdb_path:
        return pdb_path

    variables = target_dict.get("variables", {})
    pdb_path = variables.get("msvs_large_pdb_path", None)
    if pdb_path:
        return pdb_path

    pdb_base = target_dict.get("product_name", target_dict["target_name"])
    pdb_base = "{}.{}.pdb".format(pdb_base, TARGET_TYPE_EXT[target_dict["type"]])
    pdb_path = vars["PRODUCT_DIR"] + "/" + pdb_base

    return pdb_path


def InsertLargePdbShims(target_list, target_dicts, vars):
    """Insert a shim target that forces the linker to use 4KB pagesize PDBs.

    This is a workaround for targets with PDBs greater than 1GB in size, the
    limit for the 1KB pagesize PDBs created by the linker by default.

    Arguments:
      target_list: List of target pairs: 'base/base.gyp:base'.
      target_dicts: Dict of target properties keyed on target pair.
      vars: A dictionary of common GYP variables with generator-specific values.
    Returns:
      Tuple of the shimmed version of the inputs.
    """
    # Determine which targets need shimming.
    targets_to_shim = []
    for t in target_dicts:
        target_dict = target_dicts[t]

        # We only want to shim targets that have msvs_large_pdb enabled.
        if not int(target_dict.get("msvs_large_pdb", 0)):
            continue
        # This is intended for executable, shared_library and loadable_module
        # targets where every configuration is set up to produce a PDB output.
        # If any of these conditions is not true then the shim logic will fail
        # below.
        targets_to_shim.append(t)

    large_pdb_shim_cc = _GetLargePdbShimCcPath()

    for t in targets_to_shim:
        target_dict = target_dicts[t]
        target_name = target_dict.get("target_name")

        base_dict = _DeepCopySomeKeys(
            target_dict, ["configurations", "default_configuration", "toolset"]
        )

        # This is the dict for copying the source file (part of the GYP tree)
        # to the intermediate directory of the project. This is necessary because
        # we can't always build a relative path to the shim source file (on Windows
        # GYP and the project may be on different drives), and Ninja hates absolute
        # paths (it ends up generating the .obj and .obj.d alongside the source
        # file, polluting GYPs tree).
        copy_suffix = "large_pdb_copy"
        copy_target_name = target_name + "_" + copy_suffix
        full_copy_target_name = _SuffixName(t, copy_suffix)
        shim_cc_basename = os.path.basename(large_pdb_shim_cc)
        shim_cc_dir = vars["SHARED_INTERMEDIATE_DIR"] + "/" + copy_target_name
        shim_cc_path = shim_cc_dir + "/" + shim_cc_basename
        copy_dict = copy.deepcopy(base_dict)
        copy_dict["target_name"] = copy_target_name
        copy_dict["type"] = "none"
        copy_dict["sources"] = [large_pdb_shim_cc]
        copy_dict["copies"] = [
            {"destination": shim_cc_dir, "files": [large_pdb_shim_cc]}
        ]

        # This is the dict for the PDB generating shim target. It depends on the
        # copy target.
        shim_suffix = "large_pdb_shim"
        shim_target_name = target_name + "_" + shim_suffix
        full_shim_target_name = _SuffixName(t, shim_suffix)
        shim_dict = copy.deepcopy(base_dict)
        shim_dict["target_name"] = shim_target_name
        shim_dict["type"] = "static_library"
        shim_dict["sources"] = [shim_cc_path]
        shim_dict["dependencies"] = [full_copy_target_name]

        # Set up the shim to output its PDB to the same location as the final linker
        # target.
        for config_name, config in shim_dict.get("configurations").items():
            pdb_path = _GetPdbPath(target_dict, config_name, vars)

            # A few keys that we don't want to propagate.
            for key in ["msvs_precompiled_header", "msvs_precompiled_source", "test"]:
                config.pop(key, None)

            msvs = config.setdefault("msvs_settings", {})

            # Update the compiler directives in the shim target.
            compiler = msvs.setdefault("VCCLCompilerTool", {})
            compiler["DebugInformationFormat"] = "3"
            compiler["ProgramDataBaseFileName"] = pdb_path

            # Set the explicit PDB path in the appropriate configuration of the
            # original target.
            config = target_dict["configurations"][config_name]
            msvs = config.setdefault("msvs_settings", {})
            linker = msvs.setdefault("VCLinkerTool", {})
            linker["GenerateDebugInformation"] = "true"
            linker["ProgramDatabaseFile"] = pdb_path

        # Add the new targets. They must go to the beginning of the list so that
        # the dependency generation works as expected in ninja.
        target_list.insert(0, full_copy_target_name)
        target_list.insert(0, full_shim_target_name)
        target_dicts[full_copy_target_name] = copy_dict
        target_dicts[full_shim_target_name] = shim_dict

        # Update the original target to depend on the shim target.
        target_dict.setdefault("dependencies", []).append(full_shim_target_name)

    return (target_list, target_dicts)
