[PATCH 1/4] Compile-time extensions for list-object-filter
- From
Andrew Olsen via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Sep 5, 2021, 23:51 UTC
- Message-ID
- <a5383a68cc024eca9bb95fc3c24dce499efaaa19.1630885899.git.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.1031.git.1630885899.gitgitgadget@gmail.com>
From: Andrew Olsen <andrew.olsen@koordinates.com>
Adds an extension:<custom-filter> option to list-object-filters, these are implemented by static libraries that must be compiled into Git. C code changes only - Makefile changes follow.
Signed-off-by: Andrew Olsen <andrew.olsen@koordinates.com> --- .gitignore | 1 + generate-list-objects-filter-extensions.sh | 53 ++++++++++ list-objects-filter-extensions.h | 107 +++++++++++++++++++++ list-objects-filter-options.c | 47 +++++++++ list-objects-filter-options.h | 6 ++ list-objects-filter.c | 84 ++++++++++++++++ 6 files changed, 298 insertions(+) create mode 100755 generate-list-objects-filter-extensions.sh create mode 100644 list-objects-filter-extensions.h
diff --git a/.gitignore b/.gitignore index 311841f9bed..3564cb01ad7 100644 --- a/.gitignore +++ b/.gitignore @@ -190,6 +190,7 @@ /gitweb/static/gitweb.min.* /config-list.h /command-list.h +/list-objects-filter-extensions.c *.tar.gz *.dsc *.deb diff --git a/generate-list-objects-filter-extensions.sh b/generate-list-objects-filter-extensions.sh new file mode 100755 index 00000000000..422b1ce837f --- /dev/null +++ b/generate-list-objects-filter-extensions.sh @@ -0,0 +1,53 @@ +#!/bin/sh + +if [ $# -gt 0 ]; then + + # ARGS has one argument per line + ARGS=$(echo "$@" | xargs printf '%s\n') + + # Every argument should be path to a filter extension library. + INVALID_ARGS=$(echo "$ARGS" | grep -v '\.a$') + if [ -n "$INVALID_ARGS" ] ; then + printf "Error: all arguments must be paths to .a files: \n%s\n" \ + "${INVALID_ARGS}" >&2 + exit 1 + fi + + # qux/foo.a -> foo + NAMES=$(echo "$ARGS" | sed -e 's!.*/!!' -e 's!.a$!!') + + # Filter extension names must be valid C symbols so they can be linked by name. + INVALID_NAMES=$(echo "$NAMES" | grep -v '^[A-Za-z0-9_]\+$') + if [ -n "$INVALID_NAMES" ] ; then + printf "Error: all library names must also be valid C symbols: \n%s\n" \ + "${INVALID_NAMES}" >&2 + exit 1 + fi + + # foo -> filter_extension_foo + EXTS=$(echo "$NAMES" | sed -e 's!^!filter_extension_!') + + # filter_extension_foo -> [\t]filter_extension_foo, + DECLARATIONS=$(echo "$EXTS" | sed -e 's!^!\t!' -e 's!$!,!') + + # filter_extension_foo -> [\t]&filter_extension_foo, + ARRAY=$(echo "$EXTS" | sed -e 's!^!\t\&!' -e 's!$!,!') +fi + +echo '/* Automatically generated by generate-list-objects-filter-extensions.sh */' +echo +echo '#include "git-compat-util.h"' +echo '#include "list-objects-filter-extensions.h"' +echo + +if [ $# -gt 0 ]; then + echo 'extern const struct filter_extension' + echo "${DECLARATIONS%?}" + echo ';' + echo +fi + +echo 'const struct filter_extension *filter_extensions[] = {' +echo "${ARRAY}" +echo ' NULL,' +echo '};' \ No newline at end of file diff --git a/list-objects-filter-extensions.h b/list-objects-filter-extensions.h new file mode 100644 index 00000000000..35ebe1ead31 --- /dev/null +++ b/list-objects-filter-extensions.h @@ -0,0 +1,107 @@ +#ifndef GIT_LIST_OBJECTS_FILTER_EXTENSIONS_H +#define GIT_LIST_OBJECTS_FILTER_EXTENSIONS_H + +/** + * The List-Objects-Filter Extensions API can be used to develop filter + * extensions for git-upload-pack/git-rev-list/etc. + * + * See contrib/filter-extensions/README.md for more details and examples. + * + * The API defines three functions to implement a filter operation. Note that + * each filter implementing this API must compiled into Git as a static library. + * There is some plumbing in the Makefile to help with this via + * FILTER_EXTENSIONS. + * + * 1. You write a filter and compile it into your custom build of git. + * See list_objects_filter_ext_filter_fn. + * 2. A filter request is received that specifically names the filter extension + * that you have written, ie: "--filter=extension:<name>[=<arg>]" + * 3. Your list_objects_filter_ext_init_fn() is called. + * 4. Your list_objects_filter_ext_filter_fn() is called for each object + * at least once. + * 5. Your list_objects_filter_ext_free_fn() is called. + */ + +#include "list-objects-filter.h" + + +/* Whether to add or remove a specific object from any current omitset. */ +enum list_objects_filter_omit { + LOFO_KEEP = -1, + LOFO_IGNORE = 0, + LOFO_OMIT = 1, +}; + +/* + * This is a corollary to `list_objects_filter__init()` and constructs the + * filter, parsing and validating any user-provided `filter_arg` (via + * `--filter=extension:<name>=<arg>`). Use `context` for any filter-allocated + * context data. + * + * Return 0 on success and non-zero on error. + */ +typedef +int list_objects_filter_ext_init_fn( + const struct repository *r, + const char* filter_arg, + void **context +); + +/* + * This is a corollary to `list_objects_filter__free()`, destroying the filter + * and any filter-allocated context data. + */ +typedef +void list_objects_filter_ext_free_fn( + const struct repository *r, + void *context +); + +/* + * This is a corollary to `list_objects_filter__filter_object()`, and + * decides how to handle the object `obj`. + * + * omit provides a flag determining whether to explicitly add or remove + * the object from any current omitset. + */ +typedef +enum list_objects_filter_result list_objects_filter_ext_filter_fn( + const struct repository *r, + const enum list_objects_filter_situation filter_situation, + struct object *obj, + const char *pathname, + const char *filename, + enum list_objects_filter_omit *omit, + void *context +); + +/* + * To implement a filter extension called "mine", you should define + * a const struct filter_extension called filter_extension_mine, + * in the following manner: + * + * const struct filter_extension filter_extension_mine = { + * "mine", + * &my_init_fn, + * &my_filter_object_fn, + * &my_free_fn + * }; + * + * See contrib/filter-extensions/README.md for more details and examples. + */ + +struct filter_extension { + const char *name; + list_objects_filter_ext_init_fn* init_fn; + list_objects_filter_ext_filter_fn* filter_object_fn; + list_objects_filter_ext_free_fn* free_fn; +}; + +/* + * The filter_extensions array is defined in list_objects_filter_extensions.c + * which is generated at compile time from the FILTER_EXTENSIONS variable. + */ +extern const struct filter_extension *filter_extensions[]; + + +#endif /* GIT_LIST_OBJECTS_FILTER_EXTENSIONS_H */ diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c index fd8d59f653a..e92499f29c2 100644 --- a/list-objects-filter-options.c +++ b/list-objects-filter-options.c @@ -15,6 +15,11 @@ static int parse_combine_filter( const char *arg, struct strbuf *errbuf); +static int parse_extension_filter( + struct list_objects_filter_options *filter_options, + const char *arg, + struct strbuf *errbuf); + const char *list_object_filter_config_name(enum list_objects_filter_choice c) { switch (c) { @@ -31,6 +36,8 @@ const char *list_object_filter_config_name(enum list_objects_filter_choice c) return "sparse:oid"; case LOFC_OBJECT_TYPE: return "object:type"; + case LOFC_EXTENSION: + return "extension"; case LOFC_COMBINE: return "combine"; case LOFC__COUNT: @@ -91,6 +98,9 @@ static int gently_parse_list_objects_filter( filter_options->choice = LOFC_SPARSE_OID; return 0; + } else if (skip_prefix(arg, "extension:", &v0)) { + return parse_extension_filter(filter_options, v0, errbuf); + } else if (skip_prefix(arg, "sparse:path=", &v0)) { if (errbuf) { strbuf_addstr( @@ -209,6 +219,41 @@ cleanup: return result; } +static int parse_extension_filter( + struct list_objects_filter_options *filter_options, + const char *arg, + struct strbuf *errbuf) +{ + int result = 0; + struct strbuf **params = strbuf_split_str(arg, '=', 2); + + if (!params[0]) { + strbuf_addstr(errbuf, _("expected 'extension:<name>[=<parameter>]'")); + result = 1; + goto cleanup; + } + + if (params[1]) { + // This extension has a parameter. Remove trailing "=" from the name. + size_t last = params[0]->len - 1; + assert(params[0]->buf[last] == '='); + strbuf_remove(params[0], last, 1); + + filter_options->extension_value = xstrdup(params[1]->buf); + } + + filter_options->extension_name = xstrdup(params[0]->buf); + filter_options->choice = LOFC_EXTENSION; + +cleanup: + strbuf_list_free(params); + if (result) { + list_objects_filter_release(filter_options); + memset(filter_options, 0, sizeof(*filter_options)); + } + return result; +} + static int allow_unencoded(char ch) { if (ch <= ' ' || ch == '%' || ch == '+') @@ -349,6 +394,8 @@ void list_objects_filter_release( return; string_list_clear(&filter_options->filter_spec, /*free_util=*/0); free(filter_options->sparse_oid_name); + free(filter_options->extension_name); + free(filter_options->extension_value); for (sub = 0; sub < filter_options->sub_nr; sub++) list_objects_filter_release(&filter_options->sub[sub]); free(filter_options->sub); diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h index da5b6737e27..df3e360324e 100644 --- a/list-objects-filter-options.h +++ b/list-objects-filter-options.h @@ -15,6 +15,7 @@ enum list_objects_filter_choice { LOFC_TREE_DEPTH, LOFC_SPARSE_OID, LOFC_OBJECT_TYPE, + LOFC_EXTENSION, LOFC_COMBINE, LOFC__COUNT /* must be last */ }; @@ -58,6 +59,11 @@ struct list_objects_filter_options { unsigned long tree_exclude_depth; enum object_type object_type; + /* LOFC_EXTENSION values */ + + char *extension_name; + char *extension_value; + /* LOFC_COMBINE values */ /* This array contains all the subfilters which this filter combines. */ diff --git a/list-objects-filter.c b/list-objects-filter.c index 1c1ee3d1bb1..037c674b1c3 100644 --- a/list-objects-filter.c +++ b/list-objects-filter.c @@ -10,6 +10,7 @@ #include "list-objects.h" #include "list-objects-filter.h" #include "list-objects-filter-options.h" +#include "list-objects-filter-extensions.h" #include "oidmap.h" #include "oidset.h" #include "object-store.h" @@ -620,6 +621,88 @@ static void filter_object_type__init( filter->free_fn = free; } +/* + * A filter which passes the objects to a compile-time extension. + * The extension needs to implement the filter_extension interface + * defined in list-objects-filter-extension.h. + * See contrib/filter-extensions/README.md + */ + +struct filter_extension_data { + const struct filter_extension *extension; + void *context; +}; + +static enum list_objects_filter_result filter_extension_filter_object( + struct repository *r, + enum list_objects_filter_situation filter_situation, + struct object *obj, + const char *pathname, + const char *filename, + struct oidset *omits, + void *filter_data) +{ + struct filter_extension_data *d = filter_data; + + enum list_objects_filter_omit omit_it = LOFO_IGNORE; + + enum list_objects_filter_result ret = + d->extension->filter_object_fn( + r, + filter_situation, + obj, + pathname, + filename, + &omit_it, + d->context); + + if (omits) { + if (omit_it == LOFO_KEEP) + oidset_remove(omits, &obj->oid); + else if (omit_it == LOFO_OMIT) + oidset_insert(omits, &obj->oid); + } + return ret; +} + +static void filter_extension_free(void *filter_data) +{ + struct filter_extension_data *d = filter_data; + d->extension->free_fn(the_repository, d->context); + free(d); +} + +static void filter_extension__init( + struct list_objects_filter_options *filter_options, + struct filter *filter) +{ + struct filter_extension_data *d = xcalloc(1, sizeof(*d)); + int i, r; + + for (i = 0; filter_extensions[i] != NULL; i++) { + if (!strcmp( + filter_options->extension_name, + filter_extensions[i]->name)) + break; + } + if (filter_extensions[i] == NULL) { + die(_("No filter extension found with name %s"), + filter_options->extension_name); + } + d->extension = filter_extensions[i]; + + r = d->extension->init_fn( + the_repository, filter_options->extension_value, &d->context); + if (r) { + die(_("Error initialising filter extension %s: %d"), + filter_options->extension_name, r); + } + + filter->filter_data = d; + filter->filter_object_fn = &filter_extension_filter_object; + filter->free_fn = &filter_extension_free; +} + /* A filter which only shows objects shown by all sub-filters. */ struct combine_filter_data { struct subfilter *sub; @@ -767,6 +850,7 @@ static filter_init_fn s_filters[] = { filter_trees_depth__init, filter_sparse_oid__init, filter_object_type__init, + filter_extension__init, filter_combine__init, };
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