From 2fa5949d07a6aa984b1b5698e9913034b1911c33 Mon Sep 17 00:00:00 2001
From: Marshall Greenblatt <magreenblatt@gmail.com>
Date: Thu, 15 Feb 2024 15:39:15 -0500
Subject: [PATCH] alloy: Allow --remote-debugging-port=0 (fixes #3619)

---
 include/internal/cef_types.h                  | 12 ++++---
 .../devtools/devtools_manager_delegate.cc     | 33 ++++++++++---------
 2 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/include/internal/cef_types.h b/include/internal/cef_types.h
index acc707e9e..0abfe5b6b 100644
--- a/include/internal/cef_types.h
+++ b/include/internal/cef_types.h
@@ -433,10 +433,14 @@ typedef struct _cef_settings_t {
   ///
   /// Set to a value between 1024 and 65535 to enable remote debugging on the
   /// specified port. Also configurable using the "remote-debugging-port"
-  /// command-line switch. Remote debugging can be accessed by loading the
-  /// chrome://inspect page in Google Chrome. Port numbers 9222 and 9229 are
-  /// discoverable by default. Other port numbers may need to be configured via
-  /// "Discover network targets" on the Devices tab.
+  /// command-line switch. Specifying 0 via the command-line switch will result
+  /// in the selection of an ephemeral port and the port number will be printed
+  /// as part of the WebSocket endpoint URL to stderr. If a cache directory path
+  /// is provided the port will also be written to the
+  /// <cache-dir>/DevToolsActivePort file. Remote debugging can be accessed by
+  /// loading the chrome://inspect page in Google Chrome. Port numbers 9222 and
+  /// 9229 are discoverable by default. Other port numbers may need to be
+  /// configured via "Discover network targets" on the Devices tab.
   ///
   int remote_debugging_port;
 
diff --git a/libcef/browser/devtools/devtools_manager_delegate.cc b/libcef/browser/devtools/devtools_manager_delegate.cc
index 9e6de98c7..ae04915cd 100644
--- a/libcef/browser/devtools/devtools_manager_delegate.cc
+++ b/libcef/browser/devtools/devtools_manager_delegate.cc
@@ -70,28 +70,29 @@ class TCPServerSocketFactory : public content::DevToolsSocketFactory {
 std::unique_ptr<content::DevToolsSocketFactory> CreateSocketFactory() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
-  // See if the user specified a port on the command line. Specifying 0 would
-  // result in the selection of an ephemeral port but that doesn't make sense
-  // for CEF where the URL is otherwise undiscoverable. Also, don't allow
-  // binding of ports between 0 and 1024 exclusive because they're normally
-  // restricted to root on Posix-based systems.
-  uint16_t port = 0;
+  // See if the user specified a port on the command line. Specifying 0 will
+  // result in the selection of an ephemeral port and the port number will be
+  // printed as part of the WebSocket endpoint URL to stderr. If a cache
+  // directory path is provided the port will also be written to the
+  // <cache-dir>/DevToolsActivePort file.
+  //
+  // It's not allowed to bind ports between 0 and 1024 exclusive because
+  // they're normally restricted to root on Posix-based systems.
   if (command_line.HasSwitch(switches::kRemoteDebuggingPort)) {
-    int temp_port;
+    int port = 0;
     std::string port_str =
         command_line.GetSwitchValueASCII(switches::kRemoteDebuggingPort);
-    if (base::StringToInt(port_str, &temp_port) && temp_port >= 1024 &&
-        temp_port < 65535) {
-      port = static_cast<uint16_t>(temp_port);
+
+    if (base::StringToInt(port_str, &port) &&
+        (0 == port || (port >= 1024 && port < 65535))) {
+      return std::unique_ptr<content::DevToolsSocketFactory>(
+          new TCPServerSocketFactory("127.0.0.1", port));
     } else {
-      DLOG(WARNING) << "Invalid http debugger port number " << temp_port;
+      DLOG(WARNING) << "Invalid http debugger port number '" << port_str << "'";
     }
   }
-  if (port == 0) {
-    return nullptr;
-  }
-  return std::unique_ptr<content::DevToolsSocketFactory>(
-      new TCPServerSocketFactory("127.0.0.1", port));
+
+  return nullptr;
 }
 
 }  //  namespace