[Telemetry] Cause web server to keep resources in memory and thread requests.

tools/telemetry/telemetry/core/memory_cache_http_server.py

Index: tools/telemetry/telemetry/core/memory_cache_http_server.py
diff --git a/tools/telemetry/telemetry/core/memory_cache_http_server.py b/tools/telemetry/telemetry/core/memory_cache_http_server.py
new file mode 100644
index 0000000000000000000000000000000000000000..bab52aa7398f4439e9477269dd374ecd6f9af3c5
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+++ b/tools/telemetry/telemetry/core/memory_cache_http_server.py
@@ -0,0 +1,83 @@
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+import BaseHTTPServer
+import os
+import SimpleHTTPServer
+import SocketServer
+import sys
+
+
+class MemoryCacheHTTPRequestHandler(SimpleHTTPServer.SimpleHTTPRequestHandler):
+
+  def do_GET(self):
+    """Serve a GET request."""
+    resource = self.SendHead()
+    if resource:
+      self.wfile.write(resource['response'])
+
+  def do_HEAD(self):
+    """Serve a HEAD request."""
+    self.SendHead()
+
+  def SendHead(self):
+    path = self.translate_path(self.path)
+    ctype = self.guess_type(path)
+    if path not in self.server.resource_map:
+      self.send_error(404, 'File not found')
+      return None
+    resource = self.server.resource_map[path]
+    self.send_response(200)
+    self.send_header('Content-Type', ctype)
+    self.send_header('Content-Length', resource['content-length'])
+    self.send_header('Last-Modified',
+                     self.date_time_string(resource['last-modified']))
+    self.end_headers()
+    return resource
+
+
+class MemoryCacheHTTPServer(SocketServer.ThreadingMixIn,
+                            BaseHTTPServer.HTTPServer):
+  # Increase the request queue size. The default value, 5, is set in
+  # SocketServer.TCPServer (the parent of BaseHTTPServer.HTTPServer).
+  # Since we're intercepting many domains through this single server,
+  # it is quite possible to get more than 5 concurrent requests.
+  request_queue_size = 128
+
+  def __init__(self, host_port, handler, directories):
+    BaseHTTPServer.HTTPServer.__init__(self, host_port, handler)
+    self.resource_map = {}
+    for path in directories:
+      self.LoadResourceMap(path)
+
+  def LoadResourceMap(self, cwd):
+    """Loads all files in cwd into the in-memory resource map."""
+    for root, _, files in os.walk(cwd):
+      for f in files:
+        file_path = os.path.join(root, f)
+        if not os.path.exists(file_path):  # Allow for '.#' files
+          continue
+        with open(file_path, 'rb') as fd:
+          response = fd.read()
+          fs = os.fstat(fd.fileno())
+          self.resource_map[file_path] = {
+            'content-length': str(fs[6]),
+            'last-modified': fs.st_mtime,
+            'response': response
+            }
+
+
+def Main():
+  assert len(sys.argv) > 2, 'usage: %prog <port> [<path1>, <path2>, ...]'
+
+  port = int(sys.argv[1])
+  directories = sys.argv[2:]
+  server_address = ('', port)
+  MemoryCacheHTTPRequestHandler.protocol_version = 'HTTP/1.0'
+  httpd = MemoryCacheHTTPServer(server_address, MemoryCacheHTTPRequestHandler,
+                                directories)
+  httpd.serve_forever()
+
+
+if __name__ == '__main__':
+  Main()