[PATCH v5 4/9] lib: introduce json_path_cmp routine
Kirill Shcherbatov
kshcherbatov at tarantool.org
Mon Nov 26 13:49:38 MSK 2018
Introduced a new json_path_cmp routine as a part of JSON library
to compare JSON paths that may have different representation.
Need for #1012
---
src/lib/json/json.c | 28 ++++++++++++++++++++++++++++
src/lib/json/json.h | 11 +++++++++++
test/unit/json_path.c | 31 ++++++++++++++++++++++++++++++-
test/unit/json_path.result | 12 +++++++++++-
4 files changed, 80 insertions(+), 2 deletions(-)
diff --git a/src/lib/json/json.c b/src/lib/json/json.c
index 9198dca..20fbbba 100644
--- a/src/lib/json/json.c
+++ b/src/lib/json/json.c
@@ -507,3 +507,31 @@ json_tree_postorder_next(struct json_token *root, struct json_token *pos)
}
return pos->parent != root ? pos->parent : NULL;
}
+
+int
+json_path_cmp(const char *a, uint32_t a_len, const char *b, uint32_t b_len)
+{
+ struct json_lexer lexer_a, lexer_b;
+ json_lexer_create(&lexer_a, a, a_len);
+ json_lexer_create(&lexer_b, b, b_len);
+ struct json_token token_a, token_b;
+ int rc_a, rc_b;
+ while ((rc_a = json_lexer_next_token(&lexer_a, &token_a)) == 0 &&
+ (rc_b = json_lexer_next_token(&lexer_b, &token_b)) == 0 &&
+ token_a.key.type != JSON_TOKEN_END &&
+ token_b.key.type != JSON_TOKEN_END) {
+ int rc = json_token_key_cmp(&token_a, &token_b);
+ if (rc != 0)
+ return rc;
+ }
+ /* Path "a" should be valid. */
+ assert(rc_a == 0);
+ if (rc_b != 0)
+ return rc_b;
+ /*
+ * The parser stopped because the end of one of the paths
+ * was reached. As JSON_TOKEN_END > JSON_TOKEN_{NUM, STR},
+ * the path having more tokens has lower key.type value.
+ */
+ return token_b.key.type - token_a.key.type;
+}
diff --git a/src/lib/json/json.h b/src/lib/json/json.h
index dd09f5a..7d46601 100644
--- a/src/lib/json/json.h
+++ b/src/lib/json/json.h
@@ -137,6 +137,17 @@ json_lexer_create(struct json_lexer *lexer, const char *src, int src_len)
int
json_lexer_next_token(struct json_lexer *lexer, struct json_token *token);
+/**
+ * Compare two JSON paths using Lexer class.
+ * - @a path must be valid
+ * - at the case of paths that have same token-sequence prefix,
+ * the path having more tokens is assumed to be greater
+ * - when @b path contains an error, the path "a" is assumed to
+ * be greater
+ */
+int
+json_path_cmp(const char *a, uint32_t a_len, const char *b, uint32_t b_len);
+
/** Create a JSON tree object to manage data relations. */
int
json_tree_create(struct json_tree *tree);
diff --git a/test/unit/json_path.c b/test/unit/json_path.c
index f6b0472..35c2164 100644
--- a/test/unit/json_path.c
+++ b/test/unit/json_path.c
@@ -352,15 +352,44 @@ test_tree()
footer();
}
+void
+test_path_cmp()
+{
+ const char *a = "Data[1][\"FIO\"].fname";
+ uint32_t a_len = strlen(a);
+ const struct path_and_errpos rc[] = {
+ {a, 0},
+ {"[\"Data\"][1].FIO[\"fname\"]", 0},
+ {"Data[[1][\"FIO\"].fname", 6},
+ {"Data[1]", 1},
+ {"Data[1][\"FIO\"].fname[1]", -2},
+ {"Data[1][\"Info\"].fname[1]", -1},
+ };
+ header();
+ plan(lengthof(rc));
+
+ for (size_t i = 0; i < lengthof(rc); ++i) {
+ const char *path = rc[i].path;
+ int errpos = rc[i].errpos;
+ int rc = json_path_cmp(a, a_len, path, strlen(path));
+ is(rc, errpos, "path cmp result \"%s\" with \"%s\": "
+ "have %d, expected %d", a, path, rc, errpos);
+ }
+
+ check_plan();
+ footer();
+}
+
int
main()
{
header();
- plan(3);
+ plan(4);
test_basic();
test_errors();
test_tree();
+ test_path_cmp();
int rc = check_plan();
footer();
diff --git a/test/unit/json_path.result b/test/unit/json_path.result
index df68210..5c1de38 100644
--- a/test/unit/json_path.result
+++ b/test/unit/json_path.result
@@ -1,5 +1,5 @@
*** main ***
-1..3
+1..4
*** test_basic ***
1..71
ok 1 - parse <[0]>
@@ -138,4 +138,14 @@ ok 2 - subtests
ok 35 - records iterated count 4 of 4
ok 3 - subtests
*** test_tree: done ***
+ *** test_path_cmp ***
+ 1..6
+ ok 1 - path cmp result "Data[1]["FIO"].fname" with "Data[1]["FIO"].fname": have 0, expected 0
+ ok 2 - path cmp result "Data[1]["FIO"].fname" with "["Data"][1].FIO["fname"]": have 0, expected 0
+ ok 3 - path cmp result "Data[1]["FIO"].fname" with "Data[[1]["FIO"].fname": have 6, expected 6
+ ok 4 - path cmp result "Data[1]["FIO"].fname" with "Data[1]": have 1, expected 1
+ ok 5 - path cmp result "Data[1]["FIO"].fname" with "Data[1]["FIO"].fname[1]": have -2, expected -2
+ ok 6 - path cmp result "Data[1]["FIO"].fname" with "Data[1]["Info"].fname[1]": have -1, expected -1
+ok 4 - subtests
+ *** test_path_cmp: done ***
*** main: done ***
--
2.7.4
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