git/t/helper/test-parse-options.c

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#include "test-tool.h"
#include "parse-options.h"
#include "strbuf.h"
#include "string-list.h"
#include "trace2.h"
static int boolean = 0;
static int integer = 0;
static unsigned long magnitude = 0;
static timestamp_t timestamp;
static int abbrev = 7;
parse-options.c: make OPTION_COUNTUP respect "unspecified" values OPT_COUNTUP() merely increments the counter upon --option, and resets it to 0 upon --no-option, which means that there is no "unspecified" value with which a client can initialize the counter to determine whether or not --[no]-option was seen at all. Make OPT_COUNTUP() treat any negative number as an "unspecified" value to address this shortcoming. In particular, if a client initializes the counter to -1, then if it is still -1 after parse_options(), then neither --option nor --no-option was seen; if it is 0, then --no-option was seen last, and if it is 1 or greater, than --option was seen last. This change does not affect the behavior of existing clients because they all use the initial value of 0 (or more). Note that builtin/clean.c initializes the variable used with OPT__FORCE (which uses OPT_COUNTUP()) to a negative value, but it is set to either 0 or 1 by reading the configuration before the code calls parse_options(), i.e. as far as parse_options() is concerned, the initial value of the variable is not negative. To test this behavior, in test-parse-options.c, "verbose" is set to "unspecified" while quiet is set to 0 which will test the new behavior with all sets of values. Helped-by: Jeff King <peff@peff.net> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-05 09:50:00 +00:00
static int verbose = -1; /* unspecified */
static int dry_run = 0, quiet = 0;
static char *string = NULL;
static char *file = NULL;
static int ambiguous;
static struct {
int called;
const char *arg;
int unset;
} length_cb;
static int length_callback(const struct option *opt, const char *arg, int unset)
{
length_cb.called = 1;
length_cb.arg = arg;
length_cb.unset = unset;
if (unset)
return 1; /* do not support unset */
*(int *)opt->value = strlen(arg);
return 0;
}
static int number_callback(const struct option *opt, const char *arg, int unset)
{
assert NOARG/NONEG behavior of parse-options callbacks When we define a parse-options callback, the flags we put in the option struct must match what the callback expects. For example, a callback which does not handle the "unset" parameter should only be used with PARSE_OPT_NONEG. But since the callback and the option struct are not defined next to each other, it's easy to get this wrong (as earlier patches in this series show). Fortunately, the compiler can help us here: compiling with -Wunused-parameters can show us which callbacks ignore their "unset" parameters (and likewise, ones that ignore "arg" expect to be triggered with PARSE_OPT_NOARG). But after we've inspected a callback and determined that all of its callers use the right flags, what do we do next? We'd like to silence the compiler warning, but do so in a way that will catch any wrong calls in the future. We can do that by actually checking those variables and asserting that they match our expectations. Because this is such a common pattern, we'll introduce some helper macros. The resulting messages aren't as descriptive as we could make them, but the file/line information from BUG() is enough to identify the problem (and anyway, the point is that these should never be seen). Each of the annotated callbacks in this patch triggers -Wunused-parameters, and was manually inspected to make sure all callers use the correct options (so none of these BUGs should be triggerable). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-05 06:45:42 +00:00
BUG_ON_OPT_NEG(unset);
*(int *)opt->value = strtol(arg, NULL, 10);
return 0;
}
static int collect_expect(const struct option *opt, const char *arg, int unset)
{
struct string_list *expect;
struct string_list_item *item;
struct strbuf label = STRBUF_INIT;
const char *colon;
if (!arg || unset)
die("malformed --expect option");
expect = (struct string_list *)opt->value;
colon = strchr(arg, ':');
if (!colon)
die("malformed --expect option, lacking a colon");
strbuf_add(&label, arg, colon - arg);
item = string_list_insert(expect, strbuf_detach(&label, NULL));
if (item->util)
die("malformed --expect option, duplicate %s", label.buf);
item->util = (void *)arg;
return 0;
}
__attribute__((format (printf,3,4)))
static void show(struct string_list *expect, int *status, const char *fmt, ...)
{
struct string_list_item *item;
struct strbuf buf = STRBUF_INIT;
va_list args;
va_start(args, fmt);
strbuf_vaddf(&buf, fmt, args);
va_end(args);
if (!expect->nr)
printf("%s\n", buf.buf);
else {
char *colon = strchr(buf.buf, ':');
if (!colon)
die("malformed output format, output lacking colon: %s", fmt);
*colon = '\0';
item = string_list_lookup(expect, buf.buf);
*colon = ':';
if (!item)
; /* not among entries being checked */
else {
if (strcmp((const char *)item->util, buf.buf)) {
printf("-%s\n", (char *)item->util);
printf("+%s\n", buf.buf);
*status = 1;
}
}
}
strbuf_release(&buf);
}
int cmd__parse_options(int argc, const char **argv)
{
const char *prefix = "prefix/";
const char *usage[] = {
"test-tool parse-options <options>",
"",
"A helper function for the parse-options API.",
NULL
};
struct string_list expect = STRING_LIST_INIT_NODUP;
struct string_list list = STRING_LIST_INIT_NODUP;
struct option options[] = {
OPT_BOOL(0, "yes", &boolean, "get a boolean"),
OPT_BOOL('D', "no-doubt", &boolean, "begins with 'no-'"),
{ OPTION_SET_INT, 'B', "no-fear", &boolean, NULL,
"be brave", PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
OPT_COUNTUP('b', "boolean", &boolean, "increment by one"),
OPT_BIT('4', "or4", &boolean,
"bitwise-or boolean with ...0100", 4),
OPT_NEGBIT(0, "neg-or4", &boolean, "same as --no-or4", 4),
OPT_GROUP(""),
OPT_INTEGER('i', "integer", &integer, "get a integer"),
OPT_INTEGER('j', NULL, &integer, "get a integer, too"),
OPT_MAGNITUDE('m', "magnitude", &magnitude, "get a magnitude"),
OPT_SET_INT(0, "set23", &integer, "set integer to 23", 23),
OPT_CMDMODE(0, "mode1", &integer, "set integer to 1 (cmdmode option)", 1),
OPT_CMDMODE(0, "mode2", &integer, "set integer to 2 (cmdmode option)", 2),
OPT_CALLBACK('L', "length", &integer, "str",
"get length of <str>", length_callback),
OPT_FILENAME('F', "file", &file, "set file to <file>"),
OPT_GROUP("String options"),
OPT_STRING('s', "string", &string, "string", "get a string"),
OPT_STRING(0, "string2", &string, "str", "get another string"),
OPT_STRING(0, "st", &string, "st", "get another string (pervert ordering)"),
OPT_STRING('o', NULL, &string, "str", "get another string"),
OPT_NOOP_NOARG(0, "obsolete"),
OPT_SET_INT_F(0, "longhelp", &integer, "help text of this entry\n"
"spans multiple lines", 0, PARSE_OPT_NONEG),
OPT_STRING_LIST(0, "list", &list, "str", "add str to list"),
OPT_GROUP("Magic arguments"),
OPT_NUMBER_CALLBACK(&integer, "set integer to NUM",
number_callback),
{ OPTION_COUNTUP, '+', NULL, &boolean, NULL, "same as -b",
PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_NODASH },
{ OPTION_COUNTUP, 0, "ambiguous", &ambiguous, NULL,
"positive ambiguity", PARSE_OPT_NOARG | PARSE_OPT_NONEG },
{ OPTION_COUNTUP, 0, "no-ambiguous", &ambiguous, NULL,
"negative ambiguity", PARSE_OPT_NOARG | PARSE_OPT_NONEG },
OPT_GROUP("Standard options"),
OPT__ABBREV(&abbrev),
OPT__VERBOSE(&verbose, "be verbose"),
OPT__DRY_RUN(&dry_run, "dry run"),
OPT__QUIET(&quiet, "be quiet"),
OPT_CALLBACK(0, "expect", &expect, "string",
"expected output in the variable dump",
collect_expect),
OPT_GROUP("Alias"),
OPT_STRING('A', "alias-source", &string, "string", "get a string"),
OPT_ALIAS('Z', "alias-target", "alias-source"),
OPT_END(),
};
int i;
int ret = 0;
trace2_cmd_name("_parse_");
2013-04-27 19:19:47 +00:00
argc = parse_options(argc, (const char **)argv, prefix, options, usage, 0);
if (length_cb.called) {
const char *arg = length_cb.arg;
int unset = length_cb.unset;
show(&expect, &ret, "Callback: \"%s\", %d",
(arg ? arg : "not set"), unset);
}
show(&expect, &ret, "boolean: %d", boolean);
show(&expect, &ret, "integer: %d", integer);
show(&expect, &ret, "magnitude: %lu", magnitude);
show(&expect, &ret, "timestamp: %"PRItime, timestamp);
show(&expect, &ret, "string: %s", string ? string : "(not set)");
show(&expect, &ret, "abbrev: %d", abbrev);
show(&expect, &ret, "verbose: %d", verbose);
show(&expect, &ret, "quiet: %d", quiet);
show(&expect, &ret, "dry run: %s", dry_run ? "yes" : "no");
show(&expect, &ret, "file: %s", file ? file : "(not set)");
for (i = 0; i < list.nr; i++)
show(&expect, &ret, "list: %s", list.items[i].string);
for (i = 0; i < argc; i++)
show(&expect, &ret, "arg %02d: %s", i, argv[i]);
expect.strdup_strings = 1;
string_list_clear(&expect, 0);
string_list_clear(&list, 0);
return ret;
}
static void print_args(int argc, const char **argv)
{
int i;
for (i = 0; i < argc; i++)
printf("arg %02d: %s\n", i, argv[i]);
}
static int parse_options_flags__cmd(int argc, const char **argv,
enum parse_opt_flags test_flags)
{
const char *usage[] = {
"<...> cmd [options]",
NULL
};
int opt = 0;
const struct option options[] = {
OPT_INTEGER('o', "opt", &opt, "an integer option"),
OPT_END()
};
argc = parse_options(argc, argv, NULL, options, usage, test_flags);
printf("opt: %d\n", opt);
print_args(argc, argv);
return 0;
}
static enum parse_opt_flags test_flags = 0;
static const struct option test_flag_options[] = {
OPT_GROUP("flag-options:"),
OPT_BIT(0, "keep-dashdash", &test_flags,
"pass PARSE_OPT_KEEP_DASHDASH to parse_options()",
PARSE_OPT_KEEP_DASHDASH),
OPT_BIT(0, "stop-at-non-option", &test_flags,
"pass PARSE_OPT_STOP_AT_NON_OPTION to parse_options()",
PARSE_OPT_STOP_AT_NON_OPTION),
OPT_BIT(0, "keep-argv0", &test_flags,
"pass PARSE_OPT_KEEP_ARGV0 to parse_options()",
PARSE_OPT_KEEP_ARGV0),
OPT_BIT(0, "keep-unknown-opt", &test_flags,
"pass PARSE_OPT_KEEP_UNKNOWN_OPT to parse_options()",
PARSE_OPT_KEEP_UNKNOWN_OPT),
OPT_BIT(0, "no-internal-help", &test_flags,
"pass PARSE_OPT_NO_INTERNAL_HELP to parse_options()",
PARSE_OPT_NO_INTERNAL_HELP),
parse-options: add support for parsing subcommands Several Git commands have subcommands to implement mutually exclusive "operation modes", and they usually parse their subcommand argument with a bunch of if-else if statements. Teach parse-options to handle subcommands as well, which will result in shorter and simpler code with consistent error handling and error messages on unknown or missing subcommand, and it will also make possible for our Bash completion script to handle subcommands programmatically. The approach is guided by the following observations: - Most subcommands [1] are implemented in dedicated functions, and most of those functions [2] either have a signature matching the 'int cmd_foo(int argc, const char **argc, const char *prefix)' signature of builtin commands or can be trivially converted to that signature, because they miss only that last prefix parameter or have no parameters at all. - Subcommand arguments only have long form, and they have no double dash prefix, no negated form, and no description, and they don't take any arguments, and can't be abbreviated. - There must be exactly one subcommand among the arguments, or zero if the command has a default operation mode. - All arguments following the subcommand are considered to be arguments of the subcommand, and, conversely, arguments meant for the subcommand may not preceed the subcommand. So in the end subcommand declaration and parsing would look something like this: parse_opt_subcommand_fn *fn = NULL; struct option builtin_commit_graph_options[] = { OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"), N_("the object directory to store the graph")), OPT_SUBCOMMAND("verify", &fn, graph_verify), OPT_SUBCOMMAND("write", &fn, graph_write), OPT_END(), }; argc = parse_options(argc, argv, prefix, options, builtin_commit_graph_usage, 0); return fn(argc, argv, prefix); Here each OPT_SUBCOMMAND specifies the name of the subcommand and the function implementing it, and the address of the same 'fn' subcommand function pointer. parse_options() then processes the arguments until it finds the first argument matching one of the subcommands, sets 'fn' to the function associated with that subcommand, and returns, leaving the rest of the arguments unprocessed. If none of the listed subcommands is found among the arguments, parse_options() will show usage and abort. If a command has a default operation mode, 'fn' should be initialized to the function implementing that mode, and parse_options() should be invoked with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag. In this case parse_options() won't error out when not finding any subcommands, but will return leaving 'fn' unchanged. Note that if that default operation mode has any --options, then the PARSE_OPT_KEEP_UNKNOWN_OPT flag is necessary as well (otherwise parse_options() would error out upon seeing the unknown option meant to the default operation mode). Some thoughts about the implementation: - The same pointer to 'fn' must be specified as 'value' for each OPT_SUBCOMMAND, because there can be only one set of mutually exclusive subcommands; parse_options() will BUG() otherwise. There are other ways to tell parse_options() where to put the function associated with the subcommand given on the command line, but I didn't like them: - Change parse_options()'s signature by adding a pointer to subcommand function to be set to the function associated with the given subcommand, affecting all callsites, even those that don't have subcommands. - Introduce a specific parse_options_and_subcommand() variant with that extra funcion parameter. - I decided against automatically calling the subcommand function from within parse_options(), because: - There are commands that have to perform additional actions after option parsing but before calling the function implementing the specified subcommand. - The return code of the subcommand is usually the return code of the git command, but preserving the return code of the automatically called subcommand function would have made the API awkward. - Also add a OPT_SUBCOMMAND_F() variant to allow specifying an option flag: we have two subcommands that are purposefully excluded from completion ('git remote rm' and 'git stash save'), so they'll have to be specified with the PARSE_OPT_NOCOMPLETE flag. - Some of the 'parse_opt_flags' don't make sense with subcommands, and using them is probably just an oversight or misunderstanding. Therefore parse_options() will BUG() when invoked with any of the following flags while the options array contains at least one OPT_SUBCOMMAND: - PARSE_OPT_KEEP_DASHDASH: parse_options() stops parsing arguments when encountering a "--" argument, so it doesn't make sense to expect and keep one before a subcommand, because it would prevent the parsing of the subcommand. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, because the double dash might be meaningful for the command's default operation mode, e.g. to disambiguate refs and pathspecs. - PARSE_OPT_STOP_AT_NON_OPTION: As its name suggests, this flag tells parse_options() to stop as soon as it encouners a non-option argument, but subcommands are by definition not options... so how could they be parsed, then?! - PARSE_OPT_KEEP_UNKNOWN: This flag can be used to collect any unknown --options and then pass them to a different command or subsystem. Surely if a command has subcommands, then this functionality should rather be delegated to one of those subcommands, and not performed by the command itself. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, making possible to pass --options to the default operation mode. - If the command with subcommands has a default operation mode, then all arguments to the command must preceed the arguments of the subcommand. AFAICT we don't have any commands where this makes a difference, because in those commands either only the command accepts any arguments ('notes' and 'remote'), or only the default subcommand ('reflog' and 'stash'), but never both. - The 'argv' array passed to subcommand functions currently starts with the name of the subcommand. Keep this behavior. AFAICT no subcommand functions depend on the actual content of 'argv[0]', but the parse_options() call handling their options expects that the options start at argv[1]. - To support handling subcommands programmatically in our Bash completion script, 'git cmd --git-completion-helper' will now list both subcommands and regular --options, if any. This means that the completion script will have to separate subcommands (i.e. words without a double dash prefix) from --options on its own, but that's rather easy to do, and it's not much work either, because the number of subcommands a command might have is rather low, and those commands accept only a single --option or none at all. An alternative would be to introduce a separate option that lists only subcommands, but then the completion script would need not one but two git invocations and command substitutions for commands with subcommands. Note that this change doesn't affect the behavior of our Bash completion script, because when completing the --option of a command with subcommands, e.g. for 'git notes --<TAB>', then all subcommands will be filtered out anyway, as none of them will match the word to be completed starting with that double dash prefix. [1] Except 'git rerere', because many of its subcommands are implemented in the bodies of the if-else if statements parsing the command's subcommand argument. [2] Except 'credential', 'credential-store' and 'fsmonitor--daemon', because some of the functions implementing their subcommands take special parameters. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 16:04:00 +00:00
OPT_BIT(0, "subcommand-optional", &test_flags,
"pass PARSE_OPT_SUBCOMMAND_OPTIONAL to parse_options()",
PARSE_OPT_SUBCOMMAND_OPTIONAL),
OPT_END()
};
int cmd__parse_options_flags(int argc, const char **argv)
{
const char *usage[] = {
"test-tool parse-options-flags [flag-options] cmd [options]",
NULL
};
argc = parse_options(argc, argv, NULL, test_flag_options, usage,
PARSE_OPT_STOP_AT_NON_OPTION);
if (!argc || strcmp(argv[0], "cmd")) {
error("'cmd' is mandatory");
usage_with_options(usage, test_flag_options);
}
return parse_options_flags__cmd(argc, argv, test_flags);
}
parse-options: add support for parsing subcommands Several Git commands have subcommands to implement mutually exclusive "operation modes", and they usually parse their subcommand argument with a bunch of if-else if statements. Teach parse-options to handle subcommands as well, which will result in shorter and simpler code with consistent error handling and error messages on unknown or missing subcommand, and it will also make possible for our Bash completion script to handle subcommands programmatically. The approach is guided by the following observations: - Most subcommands [1] are implemented in dedicated functions, and most of those functions [2] either have a signature matching the 'int cmd_foo(int argc, const char **argc, const char *prefix)' signature of builtin commands or can be trivially converted to that signature, because they miss only that last prefix parameter or have no parameters at all. - Subcommand arguments only have long form, and they have no double dash prefix, no negated form, and no description, and they don't take any arguments, and can't be abbreviated. - There must be exactly one subcommand among the arguments, or zero if the command has a default operation mode. - All arguments following the subcommand are considered to be arguments of the subcommand, and, conversely, arguments meant for the subcommand may not preceed the subcommand. So in the end subcommand declaration and parsing would look something like this: parse_opt_subcommand_fn *fn = NULL; struct option builtin_commit_graph_options[] = { OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"), N_("the object directory to store the graph")), OPT_SUBCOMMAND("verify", &fn, graph_verify), OPT_SUBCOMMAND("write", &fn, graph_write), OPT_END(), }; argc = parse_options(argc, argv, prefix, options, builtin_commit_graph_usage, 0); return fn(argc, argv, prefix); Here each OPT_SUBCOMMAND specifies the name of the subcommand and the function implementing it, and the address of the same 'fn' subcommand function pointer. parse_options() then processes the arguments until it finds the first argument matching one of the subcommands, sets 'fn' to the function associated with that subcommand, and returns, leaving the rest of the arguments unprocessed. If none of the listed subcommands is found among the arguments, parse_options() will show usage and abort. If a command has a default operation mode, 'fn' should be initialized to the function implementing that mode, and parse_options() should be invoked with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag. In this case parse_options() won't error out when not finding any subcommands, but will return leaving 'fn' unchanged. Note that if that default operation mode has any --options, then the PARSE_OPT_KEEP_UNKNOWN_OPT flag is necessary as well (otherwise parse_options() would error out upon seeing the unknown option meant to the default operation mode). Some thoughts about the implementation: - The same pointer to 'fn' must be specified as 'value' for each OPT_SUBCOMMAND, because there can be only one set of mutually exclusive subcommands; parse_options() will BUG() otherwise. There are other ways to tell parse_options() where to put the function associated with the subcommand given on the command line, but I didn't like them: - Change parse_options()'s signature by adding a pointer to subcommand function to be set to the function associated with the given subcommand, affecting all callsites, even those that don't have subcommands. - Introduce a specific parse_options_and_subcommand() variant with that extra funcion parameter. - I decided against automatically calling the subcommand function from within parse_options(), because: - There are commands that have to perform additional actions after option parsing but before calling the function implementing the specified subcommand. - The return code of the subcommand is usually the return code of the git command, but preserving the return code of the automatically called subcommand function would have made the API awkward. - Also add a OPT_SUBCOMMAND_F() variant to allow specifying an option flag: we have two subcommands that are purposefully excluded from completion ('git remote rm' and 'git stash save'), so they'll have to be specified with the PARSE_OPT_NOCOMPLETE flag. - Some of the 'parse_opt_flags' don't make sense with subcommands, and using them is probably just an oversight or misunderstanding. Therefore parse_options() will BUG() when invoked with any of the following flags while the options array contains at least one OPT_SUBCOMMAND: - PARSE_OPT_KEEP_DASHDASH: parse_options() stops parsing arguments when encountering a "--" argument, so it doesn't make sense to expect and keep one before a subcommand, because it would prevent the parsing of the subcommand. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, because the double dash might be meaningful for the command's default operation mode, e.g. to disambiguate refs and pathspecs. - PARSE_OPT_STOP_AT_NON_OPTION: As its name suggests, this flag tells parse_options() to stop as soon as it encouners a non-option argument, but subcommands are by definition not options... so how could they be parsed, then?! - PARSE_OPT_KEEP_UNKNOWN: This flag can be used to collect any unknown --options and then pass them to a different command or subsystem. Surely if a command has subcommands, then this functionality should rather be delegated to one of those subcommands, and not performed by the command itself. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, making possible to pass --options to the default operation mode. - If the command with subcommands has a default operation mode, then all arguments to the command must preceed the arguments of the subcommand. AFAICT we don't have any commands where this makes a difference, because in those commands either only the command accepts any arguments ('notes' and 'remote'), or only the default subcommand ('reflog' and 'stash'), but never both. - The 'argv' array passed to subcommand functions currently starts with the name of the subcommand. Keep this behavior. AFAICT no subcommand functions depend on the actual content of 'argv[0]', but the parse_options() call handling their options expects that the options start at argv[1]. - To support handling subcommands programmatically in our Bash completion script, 'git cmd --git-completion-helper' will now list both subcommands and regular --options, if any. This means that the completion script will have to separate subcommands (i.e. words without a double dash prefix) from --options on its own, but that's rather easy to do, and it's not much work either, because the number of subcommands a command might have is rather low, and those commands accept only a single --option or none at all. An alternative would be to introduce a separate option that lists only subcommands, but then the completion script would need not one but two git invocations and command substitutions for commands with subcommands. Note that this change doesn't affect the behavior of our Bash completion script, because when completing the --option of a command with subcommands, e.g. for 'git notes --<TAB>', then all subcommands will be filtered out anyway, as none of them will match the word to be completed starting with that double dash prefix. [1] Except 'git rerere', because many of its subcommands are implemented in the bodies of the if-else if statements parsing the command's subcommand argument. [2] Except 'credential', 'credential-store' and 'fsmonitor--daemon', because some of the functions implementing their subcommands take special parameters. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 16:04:00 +00:00
static int subcmd_one(int argc, const char **argv, const char *prefix UNUSED)
parse-options: add support for parsing subcommands Several Git commands have subcommands to implement mutually exclusive "operation modes", and they usually parse their subcommand argument with a bunch of if-else if statements. Teach parse-options to handle subcommands as well, which will result in shorter and simpler code with consistent error handling and error messages on unknown or missing subcommand, and it will also make possible for our Bash completion script to handle subcommands programmatically. The approach is guided by the following observations: - Most subcommands [1] are implemented in dedicated functions, and most of those functions [2] either have a signature matching the 'int cmd_foo(int argc, const char **argc, const char *prefix)' signature of builtin commands or can be trivially converted to that signature, because they miss only that last prefix parameter or have no parameters at all. - Subcommand arguments only have long form, and they have no double dash prefix, no negated form, and no description, and they don't take any arguments, and can't be abbreviated. - There must be exactly one subcommand among the arguments, or zero if the command has a default operation mode. - All arguments following the subcommand are considered to be arguments of the subcommand, and, conversely, arguments meant for the subcommand may not preceed the subcommand. So in the end subcommand declaration and parsing would look something like this: parse_opt_subcommand_fn *fn = NULL; struct option builtin_commit_graph_options[] = { OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"), N_("the object directory to store the graph")), OPT_SUBCOMMAND("verify", &fn, graph_verify), OPT_SUBCOMMAND("write", &fn, graph_write), OPT_END(), }; argc = parse_options(argc, argv, prefix, options, builtin_commit_graph_usage, 0); return fn(argc, argv, prefix); Here each OPT_SUBCOMMAND specifies the name of the subcommand and the function implementing it, and the address of the same 'fn' subcommand function pointer. parse_options() then processes the arguments until it finds the first argument matching one of the subcommands, sets 'fn' to the function associated with that subcommand, and returns, leaving the rest of the arguments unprocessed. If none of the listed subcommands is found among the arguments, parse_options() will show usage and abort. If a command has a default operation mode, 'fn' should be initialized to the function implementing that mode, and parse_options() should be invoked with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag. In this case parse_options() won't error out when not finding any subcommands, but will return leaving 'fn' unchanged. Note that if that default operation mode has any --options, then the PARSE_OPT_KEEP_UNKNOWN_OPT flag is necessary as well (otherwise parse_options() would error out upon seeing the unknown option meant to the default operation mode). Some thoughts about the implementation: - The same pointer to 'fn' must be specified as 'value' for each OPT_SUBCOMMAND, because there can be only one set of mutually exclusive subcommands; parse_options() will BUG() otherwise. There are other ways to tell parse_options() where to put the function associated with the subcommand given on the command line, but I didn't like them: - Change parse_options()'s signature by adding a pointer to subcommand function to be set to the function associated with the given subcommand, affecting all callsites, even those that don't have subcommands. - Introduce a specific parse_options_and_subcommand() variant with that extra funcion parameter. - I decided against automatically calling the subcommand function from within parse_options(), because: - There are commands that have to perform additional actions after option parsing but before calling the function implementing the specified subcommand. - The return code of the subcommand is usually the return code of the git command, but preserving the return code of the automatically called subcommand function would have made the API awkward. - Also add a OPT_SUBCOMMAND_F() variant to allow specifying an option flag: we have two subcommands that are purposefully excluded from completion ('git remote rm' and 'git stash save'), so they'll have to be specified with the PARSE_OPT_NOCOMPLETE flag. - Some of the 'parse_opt_flags' don't make sense with subcommands, and using them is probably just an oversight or misunderstanding. Therefore parse_options() will BUG() when invoked with any of the following flags while the options array contains at least one OPT_SUBCOMMAND: - PARSE_OPT_KEEP_DASHDASH: parse_options() stops parsing arguments when encountering a "--" argument, so it doesn't make sense to expect and keep one before a subcommand, because it would prevent the parsing of the subcommand. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, because the double dash might be meaningful for the command's default operation mode, e.g. to disambiguate refs and pathspecs. - PARSE_OPT_STOP_AT_NON_OPTION: As its name suggests, this flag tells parse_options() to stop as soon as it encouners a non-option argument, but subcommands are by definition not options... so how could they be parsed, then?! - PARSE_OPT_KEEP_UNKNOWN: This flag can be used to collect any unknown --options and then pass them to a different command or subsystem. Surely if a command has subcommands, then this functionality should rather be delegated to one of those subcommands, and not performed by the command itself. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, making possible to pass --options to the default operation mode. - If the command with subcommands has a default operation mode, then all arguments to the command must preceed the arguments of the subcommand. AFAICT we don't have any commands where this makes a difference, because in those commands either only the command accepts any arguments ('notes' and 'remote'), or only the default subcommand ('reflog' and 'stash'), but never both. - The 'argv' array passed to subcommand functions currently starts with the name of the subcommand. Keep this behavior. AFAICT no subcommand functions depend on the actual content of 'argv[0]', but the parse_options() call handling their options expects that the options start at argv[1]. - To support handling subcommands programmatically in our Bash completion script, 'git cmd --git-completion-helper' will now list both subcommands and regular --options, if any. This means that the completion script will have to separate subcommands (i.e. words without a double dash prefix) from --options on its own, but that's rather easy to do, and it's not much work either, because the number of subcommands a command might have is rather low, and those commands accept only a single --option or none at all. An alternative would be to introduce a separate option that lists only subcommands, but then the completion script would need not one but two git invocations and command substitutions for commands with subcommands. Note that this change doesn't affect the behavior of our Bash completion script, because when completing the --option of a command with subcommands, e.g. for 'git notes --<TAB>', then all subcommands will be filtered out anyway, as none of them will match the word to be completed starting with that double dash prefix. [1] Except 'git rerere', because many of its subcommands are implemented in the bodies of the if-else if statements parsing the command's subcommand argument. [2] Except 'credential', 'credential-store' and 'fsmonitor--daemon', because some of the functions implementing their subcommands take special parameters. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 16:04:00 +00:00
{
printf("fn: subcmd_one\n");
print_args(argc, argv);
return 0;
}
static int subcmd_two(int argc, const char **argv, const char *prefix UNUSED)
parse-options: add support for parsing subcommands Several Git commands have subcommands to implement mutually exclusive "operation modes", and they usually parse their subcommand argument with a bunch of if-else if statements. Teach parse-options to handle subcommands as well, which will result in shorter and simpler code with consistent error handling and error messages on unknown or missing subcommand, and it will also make possible for our Bash completion script to handle subcommands programmatically. The approach is guided by the following observations: - Most subcommands [1] are implemented in dedicated functions, and most of those functions [2] either have a signature matching the 'int cmd_foo(int argc, const char **argc, const char *prefix)' signature of builtin commands or can be trivially converted to that signature, because they miss only that last prefix parameter or have no parameters at all. - Subcommand arguments only have long form, and they have no double dash prefix, no negated form, and no description, and they don't take any arguments, and can't be abbreviated. - There must be exactly one subcommand among the arguments, or zero if the command has a default operation mode. - All arguments following the subcommand are considered to be arguments of the subcommand, and, conversely, arguments meant for the subcommand may not preceed the subcommand. So in the end subcommand declaration and parsing would look something like this: parse_opt_subcommand_fn *fn = NULL; struct option builtin_commit_graph_options[] = { OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"), N_("the object directory to store the graph")), OPT_SUBCOMMAND("verify", &fn, graph_verify), OPT_SUBCOMMAND("write", &fn, graph_write), OPT_END(), }; argc = parse_options(argc, argv, prefix, options, builtin_commit_graph_usage, 0); return fn(argc, argv, prefix); Here each OPT_SUBCOMMAND specifies the name of the subcommand and the function implementing it, and the address of the same 'fn' subcommand function pointer. parse_options() then processes the arguments until it finds the first argument matching one of the subcommands, sets 'fn' to the function associated with that subcommand, and returns, leaving the rest of the arguments unprocessed. If none of the listed subcommands is found among the arguments, parse_options() will show usage and abort. If a command has a default operation mode, 'fn' should be initialized to the function implementing that mode, and parse_options() should be invoked with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag. In this case parse_options() won't error out when not finding any subcommands, but will return leaving 'fn' unchanged. Note that if that default operation mode has any --options, then the PARSE_OPT_KEEP_UNKNOWN_OPT flag is necessary as well (otherwise parse_options() would error out upon seeing the unknown option meant to the default operation mode). Some thoughts about the implementation: - The same pointer to 'fn' must be specified as 'value' for each OPT_SUBCOMMAND, because there can be only one set of mutually exclusive subcommands; parse_options() will BUG() otherwise. There are other ways to tell parse_options() where to put the function associated with the subcommand given on the command line, but I didn't like them: - Change parse_options()'s signature by adding a pointer to subcommand function to be set to the function associated with the given subcommand, affecting all callsites, even those that don't have subcommands. - Introduce a specific parse_options_and_subcommand() variant with that extra funcion parameter. - I decided against automatically calling the subcommand function from within parse_options(), because: - There are commands that have to perform additional actions after option parsing but before calling the function implementing the specified subcommand. - The return code of the subcommand is usually the return code of the git command, but preserving the return code of the automatically called subcommand function would have made the API awkward. - Also add a OPT_SUBCOMMAND_F() variant to allow specifying an option flag: we have two subcommands that are purposefully excluded from completion ('git remote rm' and 'git stash save'), so they'll have to be specified with the PARSE_OPT_NOCOMPLETE flag. - Some of the 'parse_opt_flags' don't make sense with subcommands, and using them is probably just an oversight or misunderstanding. Therefore parse_options() will BUG() when invoked with any of the following flags while the options array contains at least one OPT_SUBCOMMAND: - PARSE_OPT_KEEP_DASHDASH: parse_options() stops parsing arguments when encountering a "--" argument, so it doesn't make sense to expect and keep one before a subcommand, because it would prevent the parsing of the subcommand. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, because the double dash might be meaningful for the command's default operation mode, e.g. to disambiguate refs and pathspecs. - PARSE_OPT_STOP_AT_NON_OPTION: As its name suggests, this flag tells parse_options() to stop as soon as it encouners a non-option argument, but subcommands are by definition not options... so how could they be parsed, then?! - PARSE_OPT_KEEP_UNKNOWN: This flag can be used to collect any unknown --options and then pass them to a different command or subsystem. Surely if a command has subcommands, then this functionality should rather be delegated to one of those subcommands, and not performed by the command itself. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, making possible to pass --options to the default operation mode. - If the command with subcommands has a default operation mode, then all arguments to the command must preceed the arguments of the subcommand. AFAICT we don't have any commands where this makes a difference, because in those commands either only the command accepts any arguments ('notes' and 'remote'), or only the default subcommand ('reflog' and 'stash'), but never both. - The 'argv' array passed to subcommand functions currently starts with the name of the subcommand. Keep this behavior. AFAICT no subcommand functions depend on the actual content of 'argv[0]', but the parse_options() call handling their options expects that the options start at argv[1]. - To support handling subcommands programmatically in our Bash completion script, 'git cmd --git-completion-helper' will now list both subcommands and regular --options, if any. This means that the completion script will have to separate subcommands (i.e. words without a double dash prefix) from --options on its own, but that's rather easy to do, and it's not much work either, because the number of subcommands a command might have is rather low, and those commands accept only a single --option or none at all. An alternative would be to introduce a separate option that lists only subcommands, but then the completion script would need not one but two git invocations and command substitutions for commands with subcommands. Note that this change doesn't affect the behavior of our Bash completion script, because when completing the --option of a command with subcommands, e.g. for 'git notes --<TAB>', then all subcommands will be filtered out anyway, as none of them will match the word to be completed starting with that double dash prefix. [1] Except 'git rerere', because many of its subcommands are implemented in the bodies of the if-else if statements parsing the command's subcommand argument. [2] Except 'credential', 'credential-store' and 'fsmonitor--daemon', because some of the functions implementing their subcommands take special parameters. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 16:04:00 +00:00
{
printf("fn: subcmd_two\n");
print_args(argc, argv);
return 0;
}
static int parse_subcommand__cmd(int argc, const char **argv,
enum parse_opt_flags test_flags)
{
const char *usage[] = {
"<...> cmd subcmd-one",
"<...> cmd subcmd-two",
NULL
};
parse_opt_subcommand_fn *fn = NULL;
int opt = 0;
struct option options[] = {
OPT_SUBCOMMAND("subcmd-one", &fn, subcmd_one),
OPT_SUBCOMMAND("subcmd-two", &fn, subcmd_two),
OPT_INTEGER('o', "opt", &opt, "an integer option"),
OPT_END()
};
if (test_flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)
fn = subcmd_one;
argc = parse_options(argc, argv, NULL, options, usage, test_flags);
printf("opt: %d\n", opt);
return fn(argc, argv, NULL);
}
int cmd__parse_subcommand(int argc, const char **argv)
{
const char *usage[] = {
"test-tool parse-subcommand [flag-options] cmd <subcommand>",
NULL
};
argc = parse_options(argc, argv, NULL, test_flag_options, usage,
PARSE_OPT_STOP_AT_NON_OPTION);
if (!argc || strcmp(argv[0], "cmd")) {
parse-options: add support for parsing subcommands Several Git commands have subcommands to implement mutually exclusive "operation modes", and they usually parse their subcommand argument with a bunch of if-else if statements. Teach parse-options to handle subcommands as well, which will result in shorter and simpler code with consistent error handling and error messages on unknown or missing subcommand, and it will also make possible for our Bash completion script to handle subcommands programmatically. The approach is guided by the following observations: - Most subcommands [1] are implemented in dedicated functions, and most of those functions [2] either have a signature matching the 'int cmd_foo(int argc, const char **argc, const char *prefix)' signature of builtin commands or can be trivially converted to that signature, because they miss only that last prefix parameter or have no parameters at all. - Subcommand arguments only have long form, and they have no double dash prefix, no negated form, and no description, and they don't take any arguments, and can't be abbreviated. - There must be exactly one subcommand among the arguments, or zero if the command has a default operation mode. - All arguments following the subcommand are considered to be arguments of the subcommand, and, conversely, arguments meant for the subcommand may not preceed the subcommand. So in the end subcommand declaration and parsing would look something like this: parse_opt_subcommand_fn *fn = NULL; struct option builtin_commit_graph_options[] = { OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"), N_("the object directory to store the graph")), OPT_SUBCOMMAND("verify", &fn, graph_verify), OPT_SUBCOMMAND("write", &fn, graph_write), OPT_END(), }; argc = parse_options(argc, argv, prefix, options, builtin_commit_graph_usage, 0); return fn(argc, argv, prefix); Here each OPT_SUBCOMMAND specifies the name of the subcommand and the function implementing it, and the address of the same 'fn' subcommand function pointer. parse_options() then processes the arguments until it finds the first argument matching one of the subcommands, sets 'fn' to the function associated with that subcommand, and returns, leaving the rest of the arguments unprocessed. If none of the listed subcommands is found among the arguments, parse_options() will show usage and abort. If a command has a default operation mode, 'fn' should be initialized to the function implementing that mode, and parse_options() should be invoked with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag. In this case parse_options() won't error out when not finding any subcommands, but will return leaving 'fn' unchanged. Note that if that default operation mode has any --options, then the PARSE_OPT_KEEP_UNKNOWN_OPT flag is necessary as well (otherwise parse_options() would error out upon seeing the unknown option meant to the default operation mode). Some thoughts about the implementation: - The same pointer to 'fn' must be specified as 'value' for each OPT_SUBCOMMAND, because there can be only one set of mutually exclusive subcommands; parse_options() will BUG() otherwise. There are other ways to tell parse_options() where to put the function associated with the subcommand given on the command line, but I didn't like them: - Change parse_options()'s signature by adding a pointer to subcommand function to be set to the function associated with the given subcommand, affecting all callsites, even those that don't have subcommands. - Introduce a specific parse_options_and_subcommand() variant with that extra funcion parameter. - I decided against automatically calling the subcommand function from within parse_options(), because: - There are commands that have to perform additional actions after option parsing but before calling the function implementing the specified subcommand. - The return code of the subcommand is usually the return code of the git command, but preserving the return code of the automatically called subcommand function would have made the API awkward. - Also add a OPT_SUBCOMMAND_F() variant to allow specifying an option flag: we have two subcommands that are purposefully excluded from completion ('git remote rm' and 'git stash save'), so they'll have to be specified with the PARSE_OPT_NOCOMPLETE flag. - Some of the 'parse_opt_flags' don't make sense with subcommands, and using them is probably just an oversight or misunderstanding. Therefore parse_options() will BUG() when invoked with any of the following flags while the options array contains at least one OPT_SUBCOMMAND: - PARSE_OPT_KEEP_DASHDASH: parse_options() stops parsing arguments when encountering a "--" argument, so it doesn't make sense to expect and keep one before a subcommand, because it would prevent the parsing of the subcommand. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, because the double dash might be meaningful for the command's default operation mode, e.g. to disambiguate refs and pathspecs. - PARSE_OPT_STOP_AT_NON_OPTION: As its name suggests, this flag tells parse_options() to stop as soon as it encouners a non-option argument, but subcommands are by definition not options... so how could they be parsed, then?! - PARSE_OPT_KEEP_UNKNOWN: This flag can be used to collect any unknown --options and then pass them to a different command or subsystem. Surely if a command has subcommands, then this functionality should rather be delegated to one of those subcommands, and not performed by the command itself. However, this flag is allowed in combination with the PARSE_OPT_SUBCOMMAND_OPTIONAL flag, making possible to pass --options to the default operation mode. - If the command with subcommands has a default operation mode, then all arguments to the command must preceed the arguments of the subcommand. AFAICT we don't have any commands where this makes a difference, because in those commands either only the command accepts any arguments ('notes' and 'remote'), or only the default subcommand ('reflog' and 'stash'), but never both. - The 'argv' array passed to subcommand functions currently starts with the name of the subcommand. Keep this behavior. AFAICT no subcommand functions depend on the actual content of 'argv[0]', but the parse_options() call handling their options expects that the options start at argv[1]. - To support handling subcommands programmatically in our Bash completion script, 'git cmd --git-completion-helper' will now list both subcommands and regular --options, if any. This means that the completion script will have to separate subcommands (i.e. words without a double dash prefix) from --options on its own, but that's rather easy to do, and it's not much work either, because the number of subcommands a command might have is rather low, and those commands accept only a single --option or none at all. An alternative would be to introduce a separate option that lists only subcommands, but then the completion script would need not one but two git invocations and command substitutions for commands with subcommands. Note that this change doesn't affect the behavior of our Bash completion script, because when completing the --option of a command with subcommands, e.g. for 'git notes --<TAB>', then all subcommands will be filtered out anyway, as none of them will match the word to be completed starting with that double dash prefix. [1] Except 'git rerere', because many of its subcommands are implemented in the bodies of the if-else if statements parsing the command's subcommand argument. [2] Except 'credential', 'credential-store' and 'fsmonitor--daemon', because some of the functions implementing their subcommands take special parameters. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-19 16:04:00 +00:00
error("'cmd' is mandatory");
usage_with_options(usage, test_flag_options);
}
return parse_subcommand__cmd(argc, argv, test_flags);
}