diff options
Diffstat (limited to 'ipc/ipc_channel.h')
| -rw-r--r-- | ipc/ipc_channel.h | 58 |
1 files changed, 53 insertions, 5 deletions
diff --git a/ipc/ipc_channel.h b/ipc/ipc_channel.h index 132b494..c257a8e 100644 --- a/ipc/ipc_channel.h +++ b/ipc/ipc_channel.h @@ -13,6 +13,21 @@ namespace IPC { //------------------------------------------------------------------------------ +// See +// http://www.chromium.org/developers/design-documents/inter-process-communication +// for overview of IPC in Chromium. + +// Channels are implemented using named pipes on Windows, and +// socket pairs (or in some special cases unix domain sockets) on POSIX. +// On Windows we access pipes in various processes by name. +// On POSIX we pass file descriptors to child processes and assign names to them +// in a lookup table. +// In general on POSIX we do not use unix domain sockets due to security +// concerns and the fact that they can leave garbage around the file system +// (MacOS does not support abstract named unix domain sockets). +// You can use unix domain sockets if you like on POSIX by constructing the +// the channel with the mode set to one of the NAMED modes. NAMED modes are +// currently used by automation and service processes. class Channel : public Message::Sender { // Security tests need access to the pipe handle. @@ -34,12 +49,29 @@ class Channel : public Message::Sender { // Called when an error is detected that causes the channel to close. // This method is not called when a channel is closed normally. virtual void OnChannelError() {} + +#if defined(OS_POSIX) + // Called on the server side when a channel that listens for connections + // denies an attempt to connect. + virtual void OnChannelDenied() {} + + // Called on the server side when a channel that listens for connections + // has an error that causes the listening channel to close. + virtual void OnChannelListenError() {} +#endif // OS_POSIX }; enum Mode { MODE_NONE, MODE_SERVER, - MODE_CLIENT + MODE_CLIENT, + // Channels on Windows are named by default and accessible from other + // processes. On POSIX channels are anonymous by default and not accessible + // from other processes. Named channels work via named unix domain sockets. + // On Windows MODE_NAMED_SERVER == MODE_SERVER and + // MODE_NAMED_CLIENT == MODE_CLIENT. + MODE_NAMED_SERVER, + MODE_NAMED_CLIENT, }; enum { @@ -77,6 +109,10 @@ class Channel : public Message::Sender { bool Connect() WARN_UNUSED_RESULT; // Close this Channel explicitly. May be called multiple times. + // On POSIX calling close on an IPC channel that listens for connections will + // cause it to close any accepted connections, and it will stop listening for + // new connections. If you just want to close the currently accepted + // connection and listen for new ones, use ResetToAcceptingConnectionState. void Close(); // Modify the Channel's listener. @@ -92,11 +128,23 @@ class Channel : public Message::Sender { // On POSIX an IPC::Channel wraps a socketpair(), this method returns the // FD # for the client end of the socket. // This method may only be called on the server side of a channel. - // - // If the kTestingChannelID flag is specified on the command line then - // a named FIFO is used as the channel transport mechanism rather than a - // socketpair() in which case this method returns -1. int GetClientFileDescriptor() const; + + // On POSIX an IPC::Channel can either wrap an established socket, or it + // can wrap a socket that is listening for connections. Currently an + // IPC::Channel that listens for connections can only accept one connection + // at a time. + + // Returns true if the channel supports listening for connections. + bool AcceptsConnections() const; + + // Returns true if the channel supports listening for connections and is + // currently connected. + bool HasAcceptedConnection() const; + + // Closes any currently connected socket, and returns to a listening state + // for more connections. + void ResetToAcceptingConnectionState(); #endif // defined(OS_POSIX) protected: |