Source/WebCore/bindings/scripts/preprocess-idls.pl - WebKit - Git at Google

 #!/usr/bin/env perl
 #
 # Copyright (C) 2011 Google Inc.  All rights reserved.
 #
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Library General Public
 # License as published by the Free Software Foundation; either
 # version 2 of the License, or (at your option) any later version.
 #
 # This library is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 # Library General Public License for more details.
 #
 # You should have received a copy of the GNU Library General Public License
 # along with this library; see the file COPYING.LIB.  If not, write to
 # the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 # Boston, MA 02110-1301, USA.
 #

 use strict;
 use warnings;
 use FindBin;
 use lib $FindBin::Bin;

 use File::Basename;
 use Getopt::Long;
 use Cwd;
 use Config;

 my $defines;
 my $preprocessor;
 my $idlFilesList;
 my $supplementalDependencyFile;
 my $windowConstructorsFile;
 my $workerGlobalScopeConstructorsFile;
 my $dedicatedWorkerGlobalScopeConstructorsFile;
 my $serviceWorkerGlobalScopeConstructorsFile;
 my $supplementalMakefileDeps;

 GetOptions('defines=s' => \$defines,
            'preprocessor=s' => \$preprocessor,
            'idlFilesList=s' => \$idlFilesList,
            'supplementalDependencyFile=s' => \$supplementalDependencyFile,
            'windowConstructorsFile=s' => \$windowConstructorsFile,
            'workerGlobalScopeConstructorsFile=s' => \$workerGlobalScopeConstructorsFile,
            'dedicatedWorkerGlobalScopeConstructorsFile=s' => \$dedicatedWorkerGlobalScopeConstructorsFile,
            'serviceWorkerGlobalScopeConstructorsFile=s' => \$serviceWorkerGlobalScopeConstructorsFile,
            'supplementalMakefileDeps=s' => \$supplementalMakefileDeps);

 die('Must specify #define macros using --defines.') unless defined($defines);
 die('Must specify an output file using --supplementalDependencyFile.') unless defined($supplementalDependencyFile);
 die('Must specify an output file using --windowConstructorsFile.') unless defined($windowConstructorsFile);
 die('Must specify an output file using --workerGlobalScopeConstructorsFile.') unless defined($workerGlobalScopeConstructorsFile);
 die('Must specify an output file using --dedicatedWorkerGlobalScopeConstructorsFile.') unless defined($dedicatedWorkerGlobalScopeConstructorsFile);
 die('Must specify an output file using --serviceWorkerGlobalScopeConstructorsFile.') unless defined($serviceWorkerGlobalScopeConstructorsFile);
 die('Must specify the file listing all IDLs using --idlFilesList.') unless defined($idlFilesList);

 $supplementalDependencyFile = CygwinPathIfNeeded($supplementalDependencyFile);
 $windowConstructorsFile = CygwinPathIfNeeded($windowConstructorsFile);
 $workerGlobalScopeConstructorsFile = CygwinPathIfNeeded($workerGlobalScopeConstructorsFile);
 $dedicatedWorkerGlobalScopeConstructorsFile = CygwinPathIfNeeded($dedicatedWorkerGlobalScopeConstructorsFile);
 $serviceWorkerGlobalScopeConstructorsFile = CygwinPathIfNeeded($serviceWorkerGlobalScopeConstructorsFile);
 $supplementalMakefileDeps = CygwinPathIfNeeded($supplementalMakefileDeps);

 open FH, "< $idlFilesList" or die "Cannot open $idlFilesList\n";
 my @idlFilesIn = <FH>;
 chomp(@idlFilesIn);
 my @idlFiles = ();
 foreach (@idlFilesIn) {
     push @idlFiles, CygwinPathIfNeeded($_);
 }
 close FH;

 my %interfaceNameToIdlFile;
 my %idlFileToInterfaceName;
 my %supplementalDependencies;
 my %supplementals;
 my $windowConstructorsCode = "";
 my $workerGlobalScopeConstructorsCode = "";
 my $dedicatedWorkerGlobalScopeConstructorsCode = "";
 my $serviceWorkerGlobalScopeConstructorsCode = "";

 # Get rid of duplicates in idlFiles array.
 my %idlFileHash = map { $_, 1 } @idlFiles;

 # Populate $idlFileToInterfaceName and $interfaceNameToIdlFile.
 foreach my $idlFile (sort keys %idlFileHash) {
     my $fullPath = Cwd::realpath($idlFile);
     my $interfaceName = fileparse(basename($idlFile), ".idl");
     $idlFileToInterfaceName{$fullPath} = $interfaceName;
     $interfaceNameToIdlFile{$interfaceName} = $fullPath;
 }

 # Parse all IDL files.
 foreach my $idlFile (sort keys %idlFileHash) {
     my $fullPath = Cwd::realpath($idlFile);
     my $idlFileContents = getFileContents($fullPath);
     # Handle partial interfaces.
     my $partialInterfaceName = getPartialInterfaceNameFromIDL($idlFileContents);
     if ($partialInterfaceName) {
         $supplementalDependencies{$fullPath} = [$partialInterfaceName];
         next;
     }

     $supplementals{$fullPath} = [];

     # Skip if the IDL file does not contain an interface, a callback interface or an exception.
     # The IDL may contain a dictionary.
     next unless containsInterfaceOrExceptionFromIDL($idlFileContents);

     my $interfaceName = fileparse(basename($idlFile), ".idl");
     # Handle implements statements.
     my $implementedInterfaces = getImplementedInterfacesFromIDL($idlFileContents, $interfaceName);
     foreach my $implementedInterface (@{$implementedInterfaces}) {
         my $implementedIdlFile = $interfaceNameToIdlFile{$implementedInterface};
         die "Could not find a the IDL file where the following implemented interface is defined: $implementedInterface" unless $implementedIdlFile;
         if ($supplementalDependencies{$implementedIdlFile}) {
             push(@{$supplementalDependencies{$implementedIdlFile}}, $interfaceName);
         } else {
             $supplementalDependencies{$implementedIdlFile} = [$interfaceName];
         }
     }

     # For every interface that is exposed in a given ECMAScript global environment and:
     # - is a callback interface that has constants declared on it, or
     # - is a non-callback interface that is not declared with the [NoInterfaceObject] extended attribute, a corresponding
     #   property must exist on the ECMAScript environment's global object.
     # See https://heycam.github.io/webidl/#es-interfaces
     my $extendedAttributes = getInterfaceExtendedAttributesFromIDL($idlFileContents);
     unless ($extendedAttributes->{"NoInterfaceObject"}) {
         if (!isCallbackInterfaceFromIDL($idlFileContents) || interfaceHasConstantAttribute($idlFileContents)) {
             my $exposedAttribute = $extendedAttributes->{"Exposed"} || "Window";
             $exposedAttribute = substr($exposedAttribute, 1, -1) if substr($exposedAttribute, 0, 1) eq "(";
             my @globalContexts = split(",", $exposedAttribute);
             my ($attributeCode, $windowAliases) = GenerateConstructorAttributes($interfaceName, $extendedAttributes);
             foreach my $globalContext (@globalContexts) {
                 if ($globalContext eq "Window") {
                     $windowConstructorsCode .= $attributeCode;
                 } elsif ($globalContext eq "Worker") {
                     $workerGlobalScopeConstructorsCode .= $attributeCode;
                 } elsif ($globalContext eq "DedicatedWorker") {
                     $dedicatedWorkerGlobalScopeConstructorsCode .= $attributeCode;
                 } elsif ($globalContext eq "ServiceWorker") {
                     $serviceWorkerGlobalScopeConstructorsCode .= $attributeCode;
                 } else {
                     die "Unsupported global context '$globalContext' used in [Exposed] at $idlFile";
                 }
             }
             $windowConstructorsCode .= $windowAliases if $windowAliases;
         }
     }
 }

 # Generate partial interfaces for Constructors.
 GeneratePartialInterface("DOMWindow", $windowConstructorsCode, $windowConstructorsFile);
 GeneratePartialInterface("WorkerGlobalScope", $workerGlobalScopeConstructorsCode, $workerGlobalScopeConstructorsFile);
 GeneratePartialInterface("DedicatedWorkerGlobalScope", $dedicatedWorkerGlobalScopeConstructorsCode, $dedicatedWorkerGlobalScopeConstructorsFile);
 GeneratePartialInterface("ServiceWorkerGlobalScope", $serviceWorkerGlobalScopeConstructorsCode, $serviceWorkerGlobalScopeConstructorsFile);

 # Resolves partial interfaces and implements dependencies.
 foreach my $idlFile (sort keys %supplementalDependencies) {
     my $baseFiles = $supplementalDependencies{$idlFile};
     foreach my $baseFile (@{$baseFiles}) {
         my $targetIdlFile = $interfaceNameToIdlFile{$baseFile} or die "${baseFile}.idl not found, but it is supplemented by $idlFile";
         push(@{$supplementals{$targetIdlFile}}, $idlFile);
     }
     delete $supplementals{$idlFile};
 }

 # Outputs the dependency.
 # The format of a supplemental dependency file:
 #
 # DOMWindow.idl P.idl Q.idl R.idl
 # Document.idl S.idl
 # Event.idl
 # ...
 #
 # The above indicates that DOMWindow.idl is supplemented by P.idl, Q.idl and R.idl,
 # Document.idl is supplemented by S.idl, and Event.idl is supplemented by no IDLs.
 # The IDL that supplements another IDL (e.g. P.idl) never appears in the dependency file.
 my $dependencies = "";
 foreach my $idlFile (sort keys %supplementals) {
     $dependencies .= "$idlFile @{$supplementals{$idlFile}}\n";
 }
 WriteFileIfChanged($supplementalDependencyFile, $dependencies);

 if ($supplementalMakefileDeps) {
     my $makefileDeps = "";
     foreach my $idlFile (sort keys %supplementals) {
         my $basename = $idlFileToInterfaceName{$idlFile};

         my @dependencies = map { basename($_) } @{$supplementals{$idlFile}};

         $makefileDeps .= "JS${basename}.h: @{dependencies}\n";
         $makefileDeps .= "DOM${basename}.h: @{dependencies}\n";
         $makefileDeps .= "WebDOM${basename}.h: @{dependencies}\n";
         foreach my $dependency (@dependencies) {
             $makefileDeps .= "${dependency}:\n";
         }
     }

     WriteFileIfChanged($supplementalMakefileDeps, $makefileDeps);
 }

 my $cygwinPathAdded;
 sub CygwinPathIfNeeded
 {
     my $path = shift;
     if ($path && $Config{osname} eq "cygwin") {
         if (not $cygwinPathAdded) {
             $ENV{PATH} = "$ENV{PATH}:/cygdrive/c/cygwin/bin";
             $cygwinPathAdded = 1;
         }
         chomp($path = `cygpath -u '$path'`);
         $path =~ s/[\r\n]//;
     }
     return $path;
 }

 sub WriteFileIfChanged
 {
     my $fileName = shift;
     my $contents = shift;

     if (-f $fileName) {
         open FH, "<", $fileName or die "Couldn't open $fileName: $!\n";
         my @lines = <FH>;
         my $oldContents = join "", @lines;
         close FH;
         return if $contents eq $oldContents;
     }
     open FH, ">", $fileName or die "Couldn't open $fileName: $!\n";
     print FH $contents;
     close FH;
 }

 sub GeneratePartialInterface
 {
     my $interfaceName = shift;
     my $attributesCode = shift;
     my $destinationFile = shift;

     my $contents = "partial interface ${interfaceName} {\n$attributesCode};\n";
     WriteFileIfChanged($destinationFile, $contents);

     my $fullPath = Cwd::realpath($destinationFile);
     $supplementalDependencies{$fullPath} = [$interfaceName] if $interfaceNameToIdlFile{$interfaceName};
 }

 sub GenerateConstructorAttributes
 {
     my $interfaceName = shift;
     my $extendedAttributes = shift;

     my $code = "    ";
     my @extendedAttributesList;
     foreach my $attributeName (sort keys %{$extendedAttributes}) {
       next unless ($attributeName eq "Conditional" || $attributeName eq "EnabledAtRuntime" || $attributeName eq "EnabledForWorld"
         || $attributeName eq "EnabledBySetting" || $attributeName eq "SecureContext" || $attributeName eq "PrivateIdentifier"
         || $attributeName eq "PublicIdentifier");
       my $extendedAttribute = $attributeName;
       $extendedAttribute .= "=" . $extendedAttributes->{$attributeName} unless $extendedAttributes->{$attributeName} eq "VALUE_IS_MISSING";
       push(@extendedAttributesList, $extendedAttribute);
     }
     $code .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;

     my $originalInterfaceName = $interfaceName;
     $interfaceName = $extendedAttributes->{"InterfaceName"} if $extendedAttributes->{"InterfaceName"};
     $code .= "attribute " . $originalInterfaceName . "Constructor $interfaceName;\n";

     # In addition to the regular property, for every [NamedConstructor] extended attribute on an interface,
     # a corresponding property MUST exist on the ECMAScript global object.
     if ($extendedAttributes->{"NamedConstructor"}) {
         my $constructorName = $extendedAttributes->{"NamedConstructor"};
         $constructorName =~ s/\(.*//g; # Extract function name.
         $code .= "    ";
         $code .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;
         $code .= "attribute " . $originalInterfaceName . "NamedConstructor $constructorName;\n";
     }

     my $windowAliasesCode;
     if ($extendedAttributes->{"LegacyWindowAlias"}) {
         my $attributeValue = $extendedAttributes->{"LegacyWindowAlias"};
         $attributeValue = substr($attributeValue, 1, -1) if substr($attributeValue, 0, 1) eq "(";
         my @windowAliases = split(",", $attributeValue);
         foreach my $windowAlias (@windowAliases) {
             $windowAliasesCode .= "    ";
             $windowAliasesCode .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;
             $windowAliasesCode .= "attribute " . $originalInterfaceName . "Constructor $windowAlias; // Legacy Window alias.\n";
         }
     }

     return ($code, $windowAliasesCode);
 }

 sub getFileContents
 {
     my $idlFile = shift;

     open FILE, "<", $idlFile;
     my @lines = <FILE>;
     close FILE;

     # Filter out preprocessor lines.
     @lines = grep(!/^\s*#/, @lines);

     return join('', @lines);
 }

 sub getPartialInterfaceNameFromIDL
 {
     my $fileContents = shift;

     if ($fileContents =~ /partial\s+interface\s+(\w+)/gs) {
         return $1;
     }
 }

 # identifier-A implements identifier-B;
 # http://www.w3.org/TR/WebIDL/#idl-implements-statements
 sub getImplementedInterfacesFromIDL
 {
     my $fileContents = shift;
     my $interfaceName = shift;

     my @implementedInterfaces = ();
     while ($fileContents =~ /^\s*(\w+)\s+implements\s+(\w+)\s*;/mg) {
         die "Identifier on the left of the 'implements' statement should be $interfaceName in $interfaceName.idl, but found $1" if $1 ne $interfaceName;
         push(@implementedInterfaces, $2);
     }
     return \@implementedInterfaces
 }

 sub isCallbackInterfaceFromIDL
 {
     my $fileContents = shift;
     return ($fileContents =~ /callback\s+interface\s+\w+/gs);
 }

 sub containsInterfaceOrExceptionFromIDL
 {
     my $fileContents = shift;

     return 1 if $fileContents =~ /\bcallback\s+interface\s+\w+/gs;
     return 1 if $fileContents =~ /\binterface\s+\w+/gs;
     return 1 if $fileContents =~ /\bexception\s+\w+/gs;
     return 0;
 }

 sub trim
 {
     my $string = shift;
     $string =~ s/^\s+|\s+$//g;
     return $string;
 }

 sub getInterfaceExtendedAttributesFromIDL
 {
     my $fileContents = shift;

     my $extendedAttributes = {};

     # Remove comments from fileContents before processing.
     # FIX: Preference to use Regex::Common::comment, however it is not available on
     # all build systems.
     $fileContents =~ s/(?:(?:(?:\/\/)(?:[^\n]*)(?:\n))|(?:(?:\/\*)(?:(?:[^\*]+|\*(?!\/))*)(?:\*\/)))//g;

     if ($fileContents =~ /\[(.*)\]\s+(callback interface|interface|exception)\s+(\w+)/gs) {
         my @parts = split(m/,(?![^()]*\))/, $1);
         foreach my $part (@parts) {
             my @keyValue = split('=', $part);
             my $key = trim($keyValue[0]);
             next unless length($key);
             my $value = "VALUE_IS_MISSING";
             $value = trim($keyValue[1]) if @keyValue > 1;
             $extendedAttributes->{$key} = $value;
         }
     }

     return $extendedAttributes;
 }

 sub interfaceHasConstantAttribute
 {
     my $fileContents = shift;

     return $fileContents =~ /\s+const[\s\w]+=\s+[\w]+;/gs;
 }
	#!/usr/bin/env perl
	#
	# Copyright (C) 2011 Google Inc. All rights reserved.
	#
	# This library is free software; you can redistribute it and/or
	# modify it under the terms of the GNU Library General Public
	# License as published by the Free Software Foundation; either
	# version 2 of the License, or (at your option) any later version.
	#
	# This library is distributed in the hope that it will be useful,
	# but WITHOUT ANY WARRANTY; without even the implied warranty of
	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	# Library General Public License for more details.
	#
	# You should have received a copy of the GNU Library General Public License
	# along with this library; see the file COPYING.LIB. If not, write to
	# the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	# Boston, MA 02110-1301, USA.
	#

	use strict;
	use warnings;
	use FindBin;
	use lib $FindBin::Bin;

	use File::Basename;
	use Getopt::Long;
	use Cwd;
	use Config;

	my $defines;
	my $preprocessor;
	my $idlFilesList;
	my $supplementalDependencyFile;
	my $windowConstructorsFile;
	my $workerGlobalScopeConstructorsFile;
	my $dedicatedWorkerGlobalScopeConstructorsFile;
	my $serviceWorkerGlobalScopeConstructorsFile;
	my $supplementalMakefileDeps;

	GetOptions('defines=s' => \$defines,
	'preprocessor=s' => \$preprocessor,
	'idlFilesList=s' => \$idlFilesList,
	'supplementalDependencyFile=s' => \$supplementalDependencyFile,
	'windowConstructorsFile=s' => \$windowConstructorsFile,
	'workerGlobalScopeConstructorsFile=s' => \$workerGlobalScopeConstructorsFile,
	'dedicatedWorkerGlobalScopeConstructorsFile=s' => \$dedicatedWorkerGlobalScopeConstructorsFile,
	'serviceWorkerGlobalScopeConstructorsFile=s' => \$serviceWorkerGlobalScopeConstructorsFile,
	'supplementalMakefileDeps=s' => \$supplementalMakefileDeps);

	die('Must specify #define macros using --defines.') unless defined($defines);
	die('Must specify an output file using --supplementalDependencyFile.') unless defined($supplementalDependencyFile);
	die('Must specify an output file using --windowConstructorsFile.') unless defined($windowConstructorsFile);
	die('Must specify an output file using --workerGlobalScopeConstructorsFile.') unless defined($workerGlobalScopeConstructorsFile);
	die('Must specify an output file using --dedicatedWorkerGlobalScopeConstructorsFile.') unless defined($dedicatedWorkerGlobalScopeConstructorsFile);
	die('Must specify an output file using --serviceWorkerGlobalScopeConstructorsFile.') unless defined($serviceWorkerGlobalScopeConstructorsFile);
	die('Must specify the file listing all IDLs using --idlFilesList.') unless defined($idlFilesList);

	$supplementalDependencyFile = CygwinPathIfNeeded($supplementalDependencyFile);
	$windowConstructorsFile = CygwinPathIfNeeded($windowConstructorsFile);
	$workerGlobalScopeConstructorsFile = CygwinPathIfNeeded($workerGlobalScopeConstructorsFile);
	$dedicatedWorkerGlobalScopeConstructorsFile = CygwinPathIfNeeded($dedicatedWorkerGlobalScopeConstructorsFile);
	$serviceWorkerGlobalScopeConstructorsFile = CygwinPathIfNeeded($serviceWorkerGlobalScopeConstructorsFile);
	$supplementalMakefileDeps = CygwinPathIfNeeded($supplementalMakefileDeps);

	open FH, "< $idlFilesList" or die "Cannot open $idlFilesList\n";
	my @idlFilesIn = <FH>;
	chomp(@idlFilesIn);
	my @idlFiles = ();
	foreach (@idlFilesIn) {
	push @idlFiles, CygwinPathIfNeeded($_);
	}
	close FH;

	my %interfaceNameToIdlFile;
	my %idlFileToInterfaceName;
	my %supplementalDependencies;
	my %supplementals;
	my $windowConstructorsCode = "";
	my $workerGlobalScopeConstructorsCode = "";
	my $dedicatedWorkerGlobalScopeConstructorsCode = "";
	my $serviceWorkerGlobalScopeConstructorsCode = "";

	# Get rid of duplicates in idlFiles array.
	my %idlFileHash = map { $_, 1 } @idlFiles;

	# Populate $idlFileToInterfaceName and $interfaceNameToIdlFile.
	foreach my $idlFile (sort keys %idlFileHash) {
	my $fullPath = Cwd::realpath($idlFile);
	my $interfaceName = fileparse(basename($idlFile), ".idl");
	$idlFileToInterfaceName{$fullPath} = $interfaceName;
	$interfaceNameToIdlFile{$interfaceName} = $fullPath;
	}

	# Parse all IDL files.
	foreach my $idlFile (sort keys %idlFileHash) {
	my $fullPath = Cwd::realpath($idlFile);
	my $idlFileContents = getFileContents($fullPath);
	# Handle partial interfaces.
	my $partialInterfaceName = getPartialInterfaceNameFromIDL($idlFileContents);
	if ($partialInterfaceName) {
	$supplementalDependencies{$fullPath} = [$partialInterfaceName];
	next;
	}

	$supplementals{$fullPath} = [];

	# Skip if the IDL file does not contain an interface, a callback interface or an exception.
	# The IDL may contain a dictionary.
	next unless containsInterfaceOrExceptionFromIDL($idlFileContents);

	my $interfaceName = fileparse(basename($idlFile), ".idl");
	# Handle implements statements.
	my $implementedInterfaces = getImplementedInterfacesFromIDL($idlFileContents, $interfaceName);
	foreach my $implementedInterface (@{$implementedInterfaces}) {
	my $implementedIdlFile = $interfaceNameToIdlFile{$implementedInterface};
	die "Could not find a the IDL file where the following implemented interface is defined: $implementedInterface" unless $implementedIdlFile;
	if ($supplementalDependencies{$implementedIdlFile}) {
	push(@{$supplementalDependencies{$implementedIdlFile}}, $interfaceName);
	} else {
	$supplementalDependencies{$implementedIdlFile} = [$interfaceName];
	}
	}

	# For every interface that is exposed in a given ECMAScript global environment and:
	# - is a callback interface that has constants declared on it, or
	# - is a non-callback interface that is not declared with the [NoInterfaceObject] extended attribute, a corresponding
	# property must exist on the ECMAScript environment's global object.
	# See https://heycam.github.io/webidl/#es-interfaces
	my $extendedAttributes = getInterfaceExtendedAttributesFromIDL($idlFileContents);
	unless ($extendedAttributes->{"NoInterfaceObject"}) {
	if (!isCallbackInterfaceFromIDL($idlFileContents) \|\| interfaceHasConstantAttribute($idlFileContents)) {
	my $exposedAttribute = $extendedAttributes->{"Exposed"} \|\| "Window";
	$exposedAttribute = substr($exposedAttribute, 1, -1) if substr($exposedAttribute, 0, 1) eq "(";
	my @globalContexts = split(",", $exposedAttribute);
	my ($attributeCode, $windowAliases) = GenerateConstructorAttributes($interfaceName, $extendedAttributes);
	foreach my $globalContext (@globalContexts) {
	if ($globalContext eq "Window") {
	$windowConstructorsCode .= $attributeCode;
	} elsif ($globalContext eq "Worker") {
	$workerGlobalScopeConstructorsCode .= $attributeCode;
	} elsif ($globalContext eq "DedicatedWorker") {
	$dedicatedWorkerGlobalScopeConstructorsCode .= $attributeCode;
	} elsif ($globalContext eq "ServiceWorker") {
	$serviceWorkerGlobalScopeConstructorsCode .= $attributeCode;
	} else {
	die "Unsupported global context '$globalContext' used in [Exposed] at $idlFile";
	}
	}
	$windowConstructorsCode .= $windowAliases if $windowAliases;
	}
	}
	}

	# Generate partial interfaces for Constructors.
	GeneratePartialInterface("DOMWindow", $windowConstructorsCode, $windowConstructorsFile);
	GeneratePartialInterface("WorkerGlobalScope", $workerGlobalScopeConstructorsCode, $workerGlobalScopeConstructorsFile);
	GeneratePartialInterface("DedicatedWorkerGlobalScope", $dedicatedWorkerGlobalScopeConstructorsCode, $dedicatedWorkerGlobalScopeConstructorsFile);
	GeneratePartialInterface("ServiceWorkerGlobalScope", $serviceWorkerGlobalScopeConstructorsCode, $serviceWorkerGlobalScopeConstructorsFile);

	# Resolves partial interfaces and implements dependencies.
	foreach my $idlFile (sort keys %supplementalDependencies) {
	my $baseFiles = $supplementalDependencies{$idlFile};
	foreach my $baseFile (@{$baseFiles}) {
	my $targetIdlFile = $interfaceNameToIdlFile{$baseFile} or die "${baseFile}.idl not found, but it is supplemented by $idlFile";
	push(@{$supplementals{$targetIdlFile}}, $idlFile);
	}
	delete $supplementals{$idlFile};
	}

	# Outputs the dependency.
	# The format of a supplemental dependency file:
	#
	# DOMWindow.idl P.idl Q.idl R.idl
	# Document.idl S.idl
	# Event.idl
	# ...
	#
	# The above indicates that DOMWindow.idl is supplemented by P.idl, Q.idl and R.idl,
	# Document.idl is supplemented by S.idl, and Event.idl is supplemented by no IDLs.
	# The IDL that supplements another IDL (e.g. P.idl) never appears in the dependency file.
	my $dependencies = "";
	foreach my $idlFile (sort keys %supplementals) {
	$dependencies .= "$idlFile @{$supplementals{$idlFile}}\n";
	}
	WriteFileIfChanged($supplementalDependencyFile, $dependencies);

	if ($supplementalMakefileDeps) {
	my $makefileDeps = "";
	foreach my $idlFile (sort keys %supplementals) {
	my $basename = $idlFileToInterfaceName{$idlFile};

	my @dependencies = map { basename($_) } @{$supplementals{$idlFile}};

	$makefileDeps .= "JS${basename}.h: @{dependencies}\n";
	$makefileDeps .= "DOM${basename}.h: @{dependencies}\n";
	$makefileDeps .= "WebDOM${basename}.h: @{dependencies}\n";
	foreach my $dependency (@dependencies) {
	$makefileDeps .= "${dependency}:\n";
	}
	}

	WriteFileIfChanged($supplementalMakefileDeps, $makefileDeps);
	}

	my $cygwinPathAdded;
	sub CygwinPathIfNeeded
	{
	my $path = shift;
	if ($path && $Config{osname} eq "cygwin") {
	if (not $cygwinPathAdded) {
	$ENV{PATH} = "$ENV{PATH}:/cygdrive/c/cygwin/bin";
	$cygwinPathAdded = 1;
	}
	chomp($path = `cygpath -u '$path'`);
	$path =~ s/[\r\n]//;
	}
	return $path;
	}

	sub WriteFileIfChanged
	{
	my $fileName = shift;
	my $contents = shift;

	if (-f $fileName) {
	open FH, "<", $fileName or die "Couldn't open $fileName: $!\n";
	my @lines = <FH>;
	my $oldContents = join "", @lines;
	close FH;
	return if $contents eq $oldContents;
	}
	open FH, ">", $fileName or die "Couldn't open $fileName: $!\n";
	print FH $contents;
	close FH;
	}

	sub GeneratePartialInterface
	{
	my $interfaceName = shift;
	my $attributesCode = shift;
	my $destinationFile = shift;

	my $contents = "partial interface ${interfaceName} {\n$attributesCode};\n";
	WriteFileIfChanged($destinationFile, $contents);

	my $fullPath = Cwd::realpath($destinationFile);
	$supplementalDependencies{$fullPath} = [$interfaceName] if $interfaceNameToIdlFile{$interfaceName};
	}

	sub GenerateConstructorAttributes
	{
	my $interfaceName = shift;
	my $extendedAttributes = shift;

	my $code = " ";
	my @extendedAttributesList;
	foreach my $attributeName (sort keys %{$extendedAttributes}) {
	next unless ($attributeName eq "Conditional" \|\| $attributeName eq "EnabledAtRuntime" \|\| $attributeName eq "EnabledForWorld"
	\|\| $attributeName eq "EnabledBySetting" \|\| $attributeName eq "SecureContext" \|\| $attributeName eq "PrivateIdentifier"
	\|\| $attributeName eq "PublicIdentifier");
	my $extendedAttribute = $attributeName;
	$extendedAttribute .= "=" . $extendedAttributes->{$attributeName} unless $extendedAttributes->{$attributeName} eq "VALUE_IS_MISSING";
	push(@extendedAttributesList, $extendedAttribute);
	}
	$code .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;

	my $originalInterfaceName = $interfaceName;
	$interfaceName = $extendedAttributes->{"InterfaceName"} if $extendedAttributes->{"InterfaceName"};
	$code .= "attribute " . $originalInterfaceName . "Constructor $interfaceName;\n";

	# In addition to the regular property, for every [NamedConstructor] extended attribute on an interface,
	# a corresponding property MUST exist on the ECMAScript global object.
	if ($extendedAttributes->{"NamedConstructor"}) {
	my $constructorName = $extendedAttributes->{"NamedConstructor"};
	$constructorName =~ s/\(.*//g; # Extract function name.
	$code .= " ";
	$code .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;
	$code .= "attribute " . $originalInterfaceName . "NamedConstructor $constructorName;\n";
	}

	my $windowAliasesCode;
	if ($extendedAttributes->{"LegacyWindowAlias"}) {
	my $attributeValue = $extendedAttributes->{"LegacyWindowAlias"};
	$attributeValue = substr($attributeValue, 1, -1) if substr($attributeValue, 0, 1) eq "(";
	my @windowAliases = split(",", $attributeValue);
	foreach my $windowAlias (@windowAliases) {
	$windowAliasesCode .= " ";
	$windowAliasesCode .= "[" . join(', ', @extendedAttributesList) . "] " if @extendedAttributesList;
	$windowAliasesCode .= "attribute " . $originalInterfaceName . "Constructor $windowAlias; // Legacy Window alias.\n";
	}
	}

	return ($code, $windowAliasesCode);
	}

	sub getFileContents
	{
	my $idlFile = shift;

	open FILE, "<", $idlFile;
	my @lines = <FILE>;
	close FILE;

	# Filter out preprocessor lines.
	@lines = grep(!/^\s*#/, @lines);

	return join('', @lines);
	}

	sub getPartialInterfaceNameFromIDL
	{
	my $fileContents = shift;

	if ($fileContents =~ /partial\s+interface\s+(\w+)/gs) {
	return $1;
	}
	}

	# identifier-A implements identifier-B;
	# http://www.w3.org/TR/WebIDL/#idl-implements-statements
	sub getImplementedInterfacesFromIDL
	{
	my $fileContents = shift;
	my $interfaceName = shift;

	my @implementedInterfaces = ();
	while ($fileContents =~ /^\s(\w+)\s+implements\s+(\w+)\s;/mg) {
	die "Identifier on the left of the 'implements' statement should be $interfaceName in $interfaceName.idl, but found $1" if $1 ne $interfaceName;
	push(@implementedInterfaces, $2);
	}
	return \@implementedInterfaces
	}

	sub isCallbackInterfaceFromIDL
	{
	my $fileContents = shift;
	return ($fileContents =~ /callback\s+interface\s+\w+/gs);
	}

	sub containsInterfaceOrExceptionFromIDL
	{
	my $fileContents = shift;

	return 1 if $fileContents =~ /\bcallback\s+interface\s+\w+/gs;
	return 1 if $fileContents =~ /\binterface\s+\w+/gs;
	return 1 if $fileContents =~ /\bexception\s+\w+/gs;
	return 0;
	}

	sub trim
	{
	my $string = shift;
	$string =~ s/^\s+\|\s+$//g;
	return $string;
	}

	sub getInterfaceExtendedAttributesFromIDL
	{
	my $fileContents = shift;

	my $extendedAttributes = {};

	# Remove comments from fileContents before processing.
	# FIX: Preference to use Regex::Common::comment, however it is not available on
	# all build systems.
	$fileContents =~ s/(?:(?:(?:\/\/)(?:[^\n])(?:\n))\|(?:(?:\/\)(?:(?:[^\]+\|\(?!\/)))(?:\\/)))//g;

	if ($fileContents =~ /\[(.*)\]\s+(callback interface\|interface\|exception)\s+(\w+)/gs) {
	my @parts = split(m/,(?![^()]*\))/, $1);
	foreach my $part (@parts) {
	my @keyValue = split('=', $part);
	my $key = trim($keyValue[0]);
	next unless length($key);
	my $value = "VALUE_IS_MISSING";
	$value = trim($keyValue[1]) if @keyValue > 1;
	$extendedAttributes->{$key} = $value;
	}
	}

	return $extendedAttributes;
	}

	sub interfaceHasConstantAttribute
	{
	my $fileContents = shift;

	return $fileContents =~ /\s+const[\s\w]+=\s+[\w]+;/gs;
	}