bundle-uri: parse bundle.heuristic=creationToken
The bundle.heuristic value communicates that the bundle list is organized to make use of the bundle.<id>.creationToken values that may be provided in the bundle list. Those values will create a total order on the bundles, allowing the Git client to download them in a specific order and even remember previously-downloaded bundles by storing the maximum creation token value. Before implementing any logic that parses or uses the bundle.<id>.creationToken values, teach Git to parse the bundle.heuristic value from a bundle list. We can use 'test-tool bundle-uri' to print the heuristic value and verify that the parsing works correctly. As an extra precaution, create the internal 'heuristics' array to be a list of (enum, string) pairs so we can iterate through the array entries carefully, regardless of the enum values. Signed-off-by: Derrick Stolee <derrickstolee@github.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee committed
Jan 31, 2023 at 13:29 UTC
c93c3d2fa42bec64948441cb339d78e2044ff9a3
4 files changed
+74
Documentation/config/bundle.txt
+7
@@ -15,6 +15,13 @@ bundle.mode::
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complete understanding of the bundled information (`all`) or if any one
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of the listed bundle URIs is sufficient (`any`).
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+bundle.heuristic::
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+ If this string-valued key exists, then the bundle list is designed to
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+ work well with incremental `git fetch` commands. The heuristic signals
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+ that there are additional keys available for each bundle that help
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+ determine which subset of bundles the client should download. The
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+ only value currently understood is `creationToken`.
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+
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bundle.<id>.*::
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The `bundle.<id>.*` keys are used to describe a single item in the
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bundle list, grouped under `<id>` for identification purposes.
bundle-uri.c
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@@ -9,6 +9,14 @@
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#include "config.h"
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#include "remote.h"
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+static struct {
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+ enum bundle_list_heuristic heuristic;
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+ const char *name;
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+} heuristics[BUNDLE_HEURISTIC__COUNT] = {
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+ { BUNDLE_HEURISTIC_NONE, ""},
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+ { BUNDLE_HEURISTIC_CREATIONTOKEN, "creationToken" },
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+};
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+
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static int compare_bundles(const void *hashmap_cmp_fn_data,
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const struct hashmap_entry *he1,
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const struct hashmap_entry *he2,
@@ -100,6 +108,17 @@ void print_bundle_list(FILE *fp, struct bundle_list *list)
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fprintf(fp, "\tversion = %d\n", list->version);
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fprintf(fp, "\tmode = %s\n", mode);
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+ if (list->heuristic) {
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+ int i;
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+ for (i = 0; i < BUNDLE_HEURISTIC__COUNT; i++) {
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+ if (heuristics[i].heuristic == list->heuristic) {
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+ printf("\theuristic = %s\n",
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+ heuristics[list->heuristic].name);
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+ break;
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+ }
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+ }
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+ }
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+
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for_all_bundles_in_list(list, summarize_bundle, fp);
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}
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@@ -142,6 +161,21 @@ static int bundle_list_update(const char *key, const char *value,
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return 0;
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}
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+ if (!strcmp(subkey, "heuristic")) {
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+ int i;
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+ for (i = 0; i < BUNDLE_HEURISTIC__COUNT; i++) {
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+ if (heuristics[i].heuristic &&
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+ heuristics[i].name &&
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+ !strcmp(value, heuristics[i].name)) {
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+ list->heuristic = heuristics[i].heuristic;
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+ return 0;
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+ }
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+ }
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+
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+ /* Ignore unknown heuristics. */
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+ return 0;
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+ }
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+
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/* Ignore other unknown global keys. */
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return 0;
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}
bundle-uri.h
+14
@@ -52,6 +52,14 @@ enum bundle_list_mode {
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BUNDLE_MODE_ANY
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};
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+enum bundle_list_heuristic {
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+ BUNDLE_HEURISTIC_NONE = 0,
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+ BUNDLE_HEURISTIC_CREATIONTOKEN,
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+
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+ /* Must be last. */
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+ BUNDLE_HEURISTIC__COUNT
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+};
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+
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/**
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* A bundle_list contains an unordered set of remote_bundle_info structs,
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* as well as information about the bundle listing, such as version and
@@ -75,6 +83,12 @@ struct bundle_list {
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* advertised by the bundle list at that location.
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*/
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char *baseURI;
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+
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+ /**
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+ * A list can have a heuristic, which helps reduce the number of
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+ * downloaded bundles.
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+ */
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+ enum bundle_list_heuristic heuristic;
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};
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void init_bundle_list(struct bundle_list *list);
t/t5750-bundle-uri-parse.sh
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@@ -250,4 +250,23 @@ test_expect_success 'parse config format edge cases: empty key or value' '
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test_cmp_config_output expect actual
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'
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+test_expect_success 'parse config format: creationToken heuristic' '
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+ cat >expect <<-\EOF &&
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+ [bundle]
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+ version = 1
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+ mode = all
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+ heuristic = creationToken
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+ [bundle "one"]
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+ uri = http://example.com/bundle.bdl
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+ [bundle "two"]
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+ uri = https://example.com/bundle.bdl
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+ [bundle "three"]
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+ uri = file:///usr/share/git/bundle.bdl
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+ EOF
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+
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+ test-tool bundle-uri parse-config expect >actual 2>err &&
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+ test_must_be_empty err &&
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+ test_cmp_config_output expect actual
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+'
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+
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test_done