#ifndef SUBPROCESS_H #define SUBPROCESS_H #include "git-compat-util.h" #include "hashmap.h" #include "run-command.h" /* * The sub-process API makes it possible to run background sub-processes * for the entire lifetime of a Git invocation. If Git needs to communicate * with an external process multiple times, then this can reduces the process * invocation overhead. Git and the sub-process communicate through stdin and * stdout. * * The sub-processes are kept in a hashmap by command name and looked up * via the subprocess_find_entry function. If an existing instance can not * be found then a new process should be created and started. When the * parent git command terminates, all sub-processes are also terminated. * * This API is based on the run-command API. */ /* data structures */ /* Members should not be accessed directly. */ struct subprocess_entry { struct hashmap_entry ent; /* must be the first member! */ const char *cmd; struct child_process process; }; struct subprocess_capability { const char *name; /* * subprocess_handshake will "|=" this value to supported_capabilities * if the server reports that it supports this capability. */ unsigned int flag; }; /* subprocess functions */ /* Function to test two subprocess hashmap entries for equality. */ extern int cmd2process_cmp(const void *unused_cmp_data, const void *e1, const void *e2, const void *unused_keydata); /* * User-supplied function to initialize the sub-process. This is * typically used to negotiate the interface version and capabilities. */ typedef int(*subprocess_start_fn)(struct subprocess_entry *entry); /* Start a subprocess and add it to the subprocess hashmap. */ int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, subprocess_start_fn startfn); /* Kill a subprocess and remove it from the subprocess hashmap. */ void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry); /* Find a subprocess in the subprocess hashmap. */ struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd); /* subprocess helper functions */ /* Get the underlying `struct child_process` from a subprocess. */ static inline struct child_process *subprocess_get_child_process( struct subprocess_entry *entry) { return &entry->process; } /* * Perform the version and capability negotiation as described in the * "Handshake" section of long-running-process-protocol.txt using the * given requested versions and capabilities. The "versions" and "capabilities" * parameters are arrays terminated by a 0 or blank struct. * * This function is typically called when a subprocess is started (as part of * the "startfn" passed to subprocess_start). */ int subprocess_handshake(struct subprocess_entry *entry, const char *welcome_prefix, int *versions, int *chosen_version, struct subprocess_capability *capabilities, unsigned int *supported_capabilities); /* * Helper function that will read packets looking for "status=<foo>" * key/value pairs and return the value from the last "status" packet */ int subprocess_read_status(int fd, struct strbuf *status); #endif