1 files changed, 304 insertions, 0 deletions
diff --git a/Tools/gdb/webkit.py b/Tools/gdb/webkit.py
new file mode 100644
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+++ b/Tools/gdb/webkit.py
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+# Copyright (C) 2010, Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""GDB support for WebKit types.
+
+Add this to your gdb by amending your ~/.gdbinit as follows:
+  python
+  import sys
+  sys.path.insert(0, "/path/to/tools/gdb/")
+  import webkit
+"""
+
+import gdb
+import re
+import struct
+
+
+def ustring_to_string(ptr, length=None):
+    """Convert a pointer to UTF-16 data into a Python Unicode string.
+
+    ptr and length are both gdb.Value objects.
+    If length is unspecified, will guess at the length."""
+    extra = ''
+    if length is None:
+        # Try to guess at the length.
+        for i in xrange(0, 2048):
+            if int((ptr + i).dereference()) == 0:
+                length = i
+                break
+        if length is None:
+            length = 256
+            extra = u' (no trailing NUL found)'
+    else:
+        length = int(length)
+
+    char_vals = [int((ptr + i).dereference()) for i in xrange(length)]
+    string = struct.pack('H' * length, *char_vals).decode('utf-16', 'replace')
+
+    return string + extra
+
+
+class StringPrinter(object):
+    "Shared code between different string-printing classes"
+    def __init__(self, val):
+        self.val = val
+
+    def display_hint(self):
+        return 'string'
+
+
+class UCharStringPrinter(StringPrinter):
+    "Print a UChar*; we must guess at the length"
+    def to_string(self):
+        return ustring_to_string(self.val)
+
+
+class WTFAtomicStringPrinter(StringPrinter):
+    "Print a WTF::AtomicString"
+    def to_string(self):
+        return self.val['m_string']
+
+
+class WTFStringPrinter(StringPrinter):
+    "Print a WTF::String"
+    def get_length(self):
+        if not self.val['m_impl']['m_ptr']:
+            return 0
+        return self.val['m_impl']['m_ptr']['m_length']
+
+    def to_string(self):
+        if self.get_length() == 0:
+            return '(null)'
+
+        return ustring_to_string(self.val['m_impl']['m_ptr']['m_data'],
+                                 self.get_length())
+
+
+class JSCUStringPrinter(StringPrinter):
+    "Print a JSC::UString"
+    def get_length(self):
+        if not self.val['m_impl']['m_ptr']:
+            return 0
+        return self.val['m_impl']['m_ptr']['m_length']
+
+    def to_string(self):
+        if self.get_length() == 0:
+            return ''
+
+        return ustring_to_string(self.val['m_impl']['m_ptr']['m_data'],
+                                 self.get_length())
+
+
+class JSCIdentifierPrinter(StringPrinter):
+    "Print a JSC::Identifier"
+    def to_string(self):
+        return JSCUStringPrinter(self.val['m_string']).to_string()
+
+
+class JSCJSStringPrinter(StringPrinter):
+    "Print a JSC::JSString"
+    def to_string(self):
+        if self.val['m_length'] == 0:
+            return ''
+
+        return JSCUStringPrinter(self.val['m_value']).to_string()
+
+
+class WebCoreQualifiedNamePrinter(StringPrinter):
+    "Print a WebCore::QualifiedName"
+
+    def __init__(self, val):
+        super(WebCoreQualifiedNamePrinter, self).__init__(val)
+        self.prefix_length = 0
+        self.length = 0
+        if self.val['m_impl']:
+            self.prefix_printer = WTFStringPrinter(
+                self.val['m_impl']['m_prefix']['m_string'])
+            self.local_name_printer = WTFStringPrinter(
+                self.val['m_impl']['m_localName']['m_string'])
+            self.prefix_length = self.prefix_printer.get_length()
+            if self.prefix_length > 0:
+                self.length = (self.prefix_length + 1 +
+                    self.local_name_printer.get_length())
+            else:
+                self.length = self.local_name_printer.get_length()
+
+    def get_length(self):
+        return self.length
+
+    def to_string(self):
+        if self.get_length() == 0:
+            return "(null)"
+        else:
+            if self.prefix_length > 0:
+                return (self.prefix_printer.to_string() + ":" +
+                    self.local_name_printer.to_string())
+            else:
+                return self.local_name_printer.to_string()
+
+
+class WTFVectorPrinter:
+    """Pretty Printer for a WTF::Vector.
+
+    The output of this pretty printer is similar to the output of std::vector's
+    pretty printer, which is bundled in gcc.
+
+    Example gdb session should look like:
+    (gdb) p v
+    $3 = WTF::Vector of length 7, capacity 16 = {7, 17, 27, 37, 47, 57, 67}
+    (gdb) set print elements 3
+    (gdb) p v
+    $6 = WTF::Vector of length 7, capacity 16 = {7, 17, 27...}
+    (gdb) set print array
+    (gdb) p v
+    $7 = WTF::Vector of length 7, capacity 16 = {
+      7,
+      17,
+      27
+      ...
+    }
+    (gdb) set print elements 200
+    (gdb) p v
+    $8 = WTF::Vector of length 7, capacity 16 = {
+      7,
+      17,
+      27,
+      37,
+      47,
+      57,
+      67
+    }
+    """
+
+    class Iterator:
+        def __init__(self, start, finish):
+            self.item = start
+            self.finish = finish
+            self.count = 0
+
+        def __iter__(self):
+            return self
+
+        def next(self):
+            if self.item == self.finish:
+                raise StopIteration
+            count = self.count
+            self.count += 1
+            element = self.item.dereference()
+            self.item += 1
+            return ('[%d]' % count, element)
+
+    def __init__(self, val):
+        self.val = val
+
+    def children(self):
+        start = self.val['m_buffer']['m_buffer']
+        return self.Iterator(start, start + self.val['m_size'])
+
+    def to_string(self):
+        return ('%s of length %d, capacity %d'
+                % ('WTF::Vector', self.val['m_size'], self.val['m_buffer']['m_capacity']))
+
+    def display_hint(self):
+        return 'array'
+
+def add_pretty_printers():
+    pretty_printers_dict = {
+        re.compile("^WTF::Vector<.*>$"): WTFVectorPrinter,
+        re.compile("^WTF::AtomicString$"): WTFAtomicStringPrinter,
+        re.compile("^WTF::String$"): WTFStringPrinter,
+        re.compile("^WebCore::QualifiedName$"): WebCoreQualifiedNamePrinter,
+        re.compile("^JSC::UString$"): JSCUStringPrinter,
+        re.compile("^JSC::Identifier$"): JSCIdentifierPrinter,
+        re.compile("^JSC::JSString$"): JSCJSStringPrinter,
+    }
+
+    def lookup_function(val):
+        """Function used to load pretty printers; will be passed to GDB."""
+        type = val.type
+        if type.code == gdb.TYPE_CODE_REF:
+            type = type.target()
+        type = type.unqualified().strip_typedefs()
+        typename = type.tag
+        if not typename:
+            return None
+        for function, pretty_printer in pretty_printers_dict.items():
+            if function.search(typename):
+                return pretty_printer(val)
+
+        if type.code == gdb.TYPE_CODE_PTR:
+            name = str(type.target().unqualified())
+            if name == 'UChar':
+                return UCharStringPrinter(val)
+        return None
+
+    gdb.pretty_printers.append(lookup_function)
+
+
+add_pretty_printers()
+
+
+class PrintPathToRootCommand(gdb.Command):
+    """Command for printing WebKit Node trees.
+
+    Usage: printpathtoroot variable_name"""
+
+    def __init__(self):
+        super(PrintPathToRootCommand, self).__init__("printpathtoroot",
+            gdb.COMMAND_SUPPORT,
+            gdb.COMPLETE_NONE)
+
+    def invoke(self, arg, from_tty):
+        element_type = gdb.lookup_type('WebCore::Element')
+        node_type = gdb.lookup_type('WebCore::Node')
+        frame = gdb.selected_frame()
+        try:
+            val = gdb.Frame.read_var(frame, arg)
+        except:
+            print "No such variable, or invalid type"
+            return
+
+        target_type = str(val.type.target().strip_typedefs())
+        if target_type == str(node_type):
+            stack = []
+            while val:
+                stack.append([val,
+                    val.cast(element_type.pointer()).dereference()['m_tagName']])
+                val = val.dereference()['m_parent']
+
+            padding = ''
+            while len(stack) > 0:
+                pair = stack.pop()
+                print padding, pair[1], pair[0]
+                padding = padding + '  '
+        else:
+            print 'Sorry: I don\'t know how to deal with %s yet.' % target_type
+
+
+PrintPathToRootCommand()