Assorted minor cleanups in the test_json_parser module

Per gripes from Michael Paquier

Discussion: https://postgr.es/m/ZhTQ6_w1vwOhqTQI@paquier.xyz

Along the way, also clean up a handful of typos in 3311ea86ed and
ea7b4e9a2a, found by Alexander Lakhin, and a couple of stylistic
snafus noted by Daniel Westermann and Daniel Gustafsson.

src/backend/backup/basebackup_incremental.c

@@ -34,7 +34,7 @@
 #define	BLOCKS_PER_READ			512
 
 /*
- * we expect the find the last lines of the manifest, including the checksum,
+ * We expect to find the last lines of the manifest, including the checksum,
  * in the last MIN_CHUNK bytes of the manifest. We trigger an incremental
  * parse step if we are about to overflow MAX_CHUNK bytes.
  */
@@ -88,8 +88,8 @@ struct IncrementalBackupInfo
 	 * Files extracted from the backup manifest.
 	 *
 	 * We don't really need this information, because we use WAL summaries to
-	 * figure what's changed. It would be unsafe to just rely on the list of
+	 * figure out what's changed. It would be unsafe to just rely on the list
-	 * files that existed before, because it's possible for a file to be
+	 * of files that existed before, because it's possible for a file to be
 	 * removed and a new one created with the same name and different
 	 * contents. In such cases, the whole file must still be sent. We can tell
 	 * from the WAL summaries whether that happened, but not from the file

src/common/jsonapi.c

@@ -356,7 +356,7 @@ makeJsonLexContextCstringLen(JsonLexContext *lex, char *json,
  * need explicit stacks for predictions, field names and null indicators, but
  * we don't need the input, that will be handed in bit by bit to the
  * parse routine. We also need an accumulator for partial tokens in case
- * the boundary between chunks happns to fall in the middle of a token.
+ * the boundary between chunks happens to fall in the middle of a token.
  */
 #define JS_STACK_CHUNK_SIZE 64
 #define JS_MAX_PROD_LEN 10		/* more than we need */
@@ -1414,9 +1414,9 @@ json_lex(JsonLexContext *lex)
 			}
 
 			/*
-			 * Add any remaining alpha_numeric chars. This takes care of the
+			 * Add any remaining alphanumeric chars. This takes care of the
 			 * {null, false, true} literals as well as any trailing
-			 * alpha-numeric junk on non-string tokens.
+			 * alphanumeric junk on non-string tokens.
 			 */
 			for (int i = added; i < lex->input_length; i++)
 			{

src/common/parse_manifest.c

@@ -806,7 +806,7 @@ json_manifest_finalize_wal_range(JsonManifestParseState *parse)
  * the rest of the file.
  *
  * For an incremental parse, this will just be called on the last chunk of the
- * manifest, and the cryptohash context paswed in. For a non-incremental
+ * manifest, and the cryptohash context passed in. For a non-incremental
  * parse incr_ctx will be NULL.
  */
 static void

src/test/modules/test_json_parser/README

@@ -4,22 +4,21 @@ Module `test_json_parser`
 This module contains two programs for testing the json parsers.
 
 - `test_json_parser_incremental` is for testing the incremental parser, It
-  reads in a file and pases it in very small chunks (60 bytes at a time) to
+  reads in a file and passes it in very small chunks (default is 60 bytes at a
-  the incremental parser. It's not meant to be a speed test but to test the
+  time) to the incremental parser. It's not meant to be a speed test but to
-  accuracy of the incremental parser. It takes one argument: the name of the
+  test the accuracy of the incremental parser.  There are two option arguments,
-  input file.
+  "-c nn" specifies an alternative chunk size, and "-s" specifies using
+  semantic routines. The semantic routines re-output the json, although not in
+  a very pretty form. The required non-option argument is the input file name.
 - `test_json_parser_perf` is for speed testing both the standard
   recursive descent parser and the non-recursive incremental
   parser. If given the `-i` flag it uses the non-recursive parser,
-  otherwise the stardard parser. The remaining flags are the number of
+  otherwise the standard parser. The remaining flags are the number of
   parsing iterations and the file containing the input. Even when
   using the non-recursive parser, the input is passed to the parser in a
   single chunk. The results are thus comparable to those of the
   standard parser.
 
-The easiest way to use these is to run `make check` and `make speed-check`
+The sample input file is a small, sanitized extract from a list of `delicious`
-
-The sample input file is a small extract from a list of `delicious`
 bookmarks taken some years ago, all wrapped in a single json
-array. 10,000 iterations of parsing this file gives a reasonable
+array.
-benchmark, and that is what the `speed-check` target does.

src/test/modules/test_json_parser/test_json_parser_incremental.c

@@ -3,16 +3,17 @@
  * test_json_parser_incremental.c
  *    Test program for incremental JSON parser
  *
- * Copyright (c) 2023, PostgreSQL Global Development Group
+ * Copyright (c) 2024, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
  *    src/test/modules/test_json_parser/test_json_parser_incremental.c
  *
- * This progam tests incremental parsing of json. The input is fed into
+ * This program tests incremental parsing of json. The input is fed into
  * the parser in very small chunks. In practice you would normally use
  * much larger chunks, but doing this makes it more likely that the
- * full range of incement handling, especially in the lexer, is exercised.
+ * full range of increment handling, especially in the lexer, is exercised.
- * If the "-c SIZE" option is provided, that chunk size is used instead.
+ * If the "-c SIZE" option is provided, that chunk size is used instead
+ * of the default of 60.
  *
  * The argument specifies the file containing the JSON input.
  *
@@ -31,6 +32,9 @@
 #include "mb/pg_wchar.h"
 #include "pg_getopt.h"
 
+#define BUFSIZE 6000
+#define DEFAULT_CHUNK_SIZE 60
+
 typedef struct DoState
 {
 	JsonLexContext *lex;
@@ -67,14 +71,13 @@ JsonSemAction sem = {
 int
 main(int argc, char **argv)
 {
-	/* max delicious line length is less than this */
+	char		buff[BUFSIZE];
-	char		buff[6001];
 	FILE	   *json_file;
 	JsonParseErrorType result;
 	JsonLexContext lex;
 	StringInfoData json;
 	int			n_read;
-	size_t		chunk_size = 60;
+	size_t		chunk_size = DEFAULT_CHUNK_SIZE;
 	struct stat statbuf;
 	off_t		bytes_left;
 	JsonSemAction *testsem = &nullSemAction;
@@ -88,6 +91,11 @@ main(int argc, char **argv)
 		{
 			case 'c':			/* chunksize */
 				sscanf(optarg, "%zu", &chunk_size);
+				if (chunk_size > BUFSIZE)
+				{
+					fprintf(stderr, "chunk size cannot exceed %d\n", BUFSIZE);
+					exit(1);
+				}
 				break;
 			case 's':			/* do semantic processing */
 				testsem = &sem;
@@ -121,6 +129,12 @@ main(int argc, char **argv)
 	{
 		n_read = fread(buff, 1, chunk_size, json_file);
 		appendBinaryStringInfo(&json, buff, n_read);
+
+		/*
+		 * Append some trailing junk to the buffer passed to the parser. This
+		 * helps us ensure that the parser does the right thing even if the
+		 * chunk isn't terminated with a '\0'.
+		 */
 		appendStringInfoString(&json, "1+23 trailing junk");
 		bytes_left -= n_read;
 		if (bytes_left > 0)

src/test/modules/test_json_parser/test_json_parser_perf.c

@@ -1,14 +1,14 @@
 /*-------------------------------------------------------------------------
  *
  * test_json_parser_perf.c
- *    Performancet est program for both flavors of the JSON parser
+ *    Performance test program for both flavors of the JSON parser
  *
- * Copyright (c) 2023, PostgreSQL Global Development Group
+ * Copyright (c) 2024, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
  *    src/test/modules/test_json_parser/test_json_parser_perf.c
  *
- * This progam tests either the standard (recursive descent) JSON parser
+ * This program tests either the standard (recursive descent) JSON parser
  * or the incremental (table driven) parser, but without breaking the input
  * into chunks in the latter case. Thus it can be used to compare the pure
  * parsing speed of the two parsers. If the "-i" option is used, then the
@@ -28,11 +28,12 @@
 #include <stdio.h>
 #include <string.h>
 
+#define BUFSIZE 6000
+
 int
 main(int argc, char **argv)
 {
-	/* max delicious line length is less than this */
+	char		buff[BUFSIZE];
-	char		buff[6001];
 	FILE	   *json_file;
 	JsonParseErrorType result;
 	JsonLexContext *lex;