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99605d62 BP |
1 | #ifndef SUBPROCESS_H |
2 | #define SUBPROCESS_H | |
3 | ||
99605d62 BP |
4 | #include "hashmap.h" |
5 | #include "run-command.h" | |
6 | ||
7 | /* | |
7e2e1bbb JT |
8 | * The sub-process API makes it possible to run background sub-processes |
9 | * for the entire lifetime of a Git invocation. If Git needs to communicate | |
10 | * with an external process multiple times, then this can reduces the process | |
11 | * invocation overhead. Git and the sub-process communicate through stdin and | |
12 | * stdout. | |
13 | * | |
14 | * The sub-processes are kept in a hashmap by command name and looked up | |
15 | * via the subprocess_find_entry function. If an existing instance can not | |
16 | * be found then a new process should be created and started. When the | |
17 | * parent git command terminates, all sub-processes are also terminated. | |
18 | * | |
19 | * This API is based on the run-command API. | |
99605d62 BP |
20 | */ |
21 | ||
22 | /* data structures */ | |
23 | ||
7e2e1bbb | 24 | /* Members should not be accessed directly. */ |
99605d62 | 25 | struct subprocess_entry { |
e2b5038d | 26 | struct hashmap_entry ent; |
99605d62 BP |
27 | const char *cmd; |
28 | struct child_process process; | |
29 | }; | |
30 | ||
fa64a2fd JT |
31 | struct subprocess_capability { |
32 | const char *name; | |
33 | ||
34 | /* | |
35 | * subprocess_handshake will "|=" this value to supported_capabilities | |
36 | * if the server reports that it supports this capability. | |
37 | */ | |
38 | unsigned int flag; | |
39 | }; | |
40 | ||
99605d62 BP |
41 | /* subprocess functions */ |
42 | ||
7e2e1bbb | 43 | /* Function to test two subprocess hashmap entries for equality. */ |
55454427 | 44 | int cmd2process_cmp(const void *unused_cmp_data, |
939af16e EW |
45 | const struct hashmap_entry *e, |
46 | const struct hashmap_entry *entry_or_key, | |
ad6dad09 | 47 | const void *unused_keydata); |
99605d62 | 48 | |
7e2e1bbb JT |
49 | /* |
50 | * User-supplied function to initialize the sub-process. This is | |
51 | * typically used to negotiate the interface version and capabilities. | |
52 | */ | |
99605d62 | 53 | typedef int(*subprocess_start_fn)(struct subprocess_entry *entry); |
7e2e1bbb JT |
54 | |
55 | /* Start a subprocess and add it to the subprocess hashmap. */ | |
99605d62 BP |
56 | int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, |
57 | subprocess_start_fn startfn); | |
58 | ||
7e2e1bbb | 59 | /* Kill a subprocess and remove it from the subprocess hashmap. */ |
99605d62 BP |
60 | void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry); |
61 | ||
7e2e1bbb | 62 | /* Find a subprocess in the subprocess hashmap. */ |
99605d62 BP |
63 | struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd); |
64 | ||
65 | /* subprocess helper functions */ | |
66 | ||
7e2e1bbb | 67 | /* Get the underlying `struct child_process` from a subprocess. */ |
99605d62 BP |
68 | static inline struct child_process *subprocess_get_child_process( |
69 | struct subprocess_entry *entry) | |
70 | { | |
71 | return &entry->process; | |
72 | } | |
73 | ||
fa64a2fd | 74 | /* |
addad105 JT |
75 | * Perform the version and capability negotiation as described in the |
76 | * "Handshake" section of long-running-process-protocol.txt using the | |
fa64a2fd JT |
77 | * given requested versions and capabilities. The "versions" and "capabilities" |
78 | * parameters are arrays terminated by a 0 or blank struct. | |
79 | * | |
80 | * This function is typically called when a subprocess is started (as part of | |
81 | * the "startfn" passed to subprocess_start). | |
82 | */ | |
83 | int subprocess_handshake(struct subprocess_entry *entry, | |
84 | const char *welcome_prefix, | |
85 | int *versions, | |
86 | int *chosen_version, | |
87 | struct subprocess_capability *capabilities, | |
88 | unsigned int *supported_capabilities); | |
89 | ||
99605d62 BP |
90 | /* |
91 | * Helper function that will read packets looking for "status=<foo>" | |
92 | * key/value pairs and return the value from the last "status" packet | |
93 | */ | |
94 | ||
4f2a2e9f | 95 | int subprocess_read_status(int fd, struct strbuf *status); |
99605d62 BP |
96 | |
97 | #endif |