Reduce Warnings - Code Consistency and Quality Improvements (#1543)

CDRIVER-5305 - Address the following warnings:

* -Wcast-function-type
* -Wcomma
* -Wconditional-uninitialized
* -Wextra-semi-stmt
* -Wnull-pointer-subtraction
* -Wold-style-declaration
* -Wunreachable-code
* -Wunused-parameter

Author: eramongodb

src/common/common-md5.c

@@ -169,7 +169,7 @@ bson_md5_process (bson_md5_t *md5, const uint8_t *data)
           * On little-endian machines, we can process properly aligned
           * data without copying it.
           */
-         if (!((data - (const uint8_t *) 0) & 3)) {
+         if (!(((uintptr_t) data) & 3u)) {
 /* data are properly aligned */
 #ifdef __clang__
 #pragma clang diagnostic push

src/libbson/examples/bson-streaming-reader.c

@@ -52,7 +52,8 @@
 int
 bson_streaming_remote_open (const char *hostname, const char *port)
 {
-   int error, sock;
+   int error = 0;
+   int sock = 0;
    struct addrinfo hints, *ptr, *server_list;
 
    /*

src/libbson/examples/creating.c

@@ -17,7 +17,7 @@
 #include <bson/bson.h>
 
 int
-main (int argc, const char **argv)
+main (void)
 {
    {
       // bson_append_document_begin example ... begin

src/libbson/src/bson/bson-decimal128.c

@@ -32,15 +32,17 @@
 #define BSON_DECIMAL128_MAX_DIGITS 34
 
 #define BSON_DECIMAL128_SET_NAN(dec)      \
-   do {                                   \
+   if (1) {                               \
       (dec).high = 0x7c00000000000000ull; \
       (dec).low = 0;                      \
-   } while (0);
+   } else                                 \
+      (void) 0
 #define BSON_DECIMAL128_SET_INF(dec, isneg)                                 \
-   do {                                                                     \
+   if (1) {                                                                 \
       (dec).high = 0x7800000000000000ull + 0x8000000000000000ull * (isneg); \
       (dec).low = 0;                                                        \
-   } while (0);
+   } else                                                                   \
+      (void) 0
 
 /**
  * _bson_uint128_t:
@@ -163,8 +165,10 @@ bson_decimal128_to_string (const bson_decimal128_t *dec, /* IN  */
       *(str_out++) = '-';
    }
 
-   low = (uint32_t) dec->low, midl = (uint32_t) (dec->low >> 32),
-   midh = (uint32_t) dec->high, high = (uint32_t) (dec->high >> 32);
+   low = (uint32_t) dec->low;
+   midl = (uint32_t) (dec->low >> 32);
+   midh = (uint32_t) dec->high;
+   high = (uint32_t) (dec->high >> 32);
 
    /* Decode combination field and exponent */
    combination = (high >> 26) & COMBINATION_MASK;

src/libbson/src/bson/bson-json.c

@@ -347,15 +347,16 @@ _noop (void)
    do {                                 \
       STACK_POP_DOC (_noop ());         \
       bson->code_data.in_scope = false; \
-   } while (0);
+   } while (0)
 #define STACK_POP_DBPOINTER STACK_POP_DOC (_noop ())
 #define BASIC_CB_PREAMBLE                         \
    const char *key;                               \
    size_t len;                                    \
    bson_json_reader_bson_t *bson = &reader->bson; \
    _bson_json_read_fixup_key (bson);              \
    key = bson->key;                               \
-   len = bson->key_buf.len;
+   len = bson->key_buf.len;                       \
+   (void) 0
 #define BASIC_CB_BAIL_IF_NOT_NORMAL(_type)                                     \
    if (bson->read_state != BSON_JSON_REGULAR) {                                \
       _bson_json_read_set_error (reader,                                       \
@@ -369,7 +370,8 @@ _noop (void)
                                  (_type),                                      \
                                  read_state_names[bson->read_state]);          \
       return;                                                                  \
-   }
+   } else                                                                      \
+      (void) 0
 #define HANDLE_OPTION(_selection_statement, _key, _type, _state)               \
    _selection_statement (len == strlen (_key) &&                               \
                          strncmp ((const char *) val, (_key), len) == 0)       \

src/libbson/tests/test-bson.c

@@ -290,7 +290,7 @@ test_bson_append_array (void)
 static void
 test_bson_append_binary (void)
 {
-   const static uint8_t binary[] = {'1', '2', '3', '4'};
+   static const uint8_t binary[] = {'1', '2', '3', '4'};
    bson_t *b;
    bson_t *b2;
 
@@ -307,7 +307,7 @@ test_bson_append_binary (void)
 static void
 test_bson_append_binary_deprecated (void)
 {
-   const static uint8_t binary[] = {'1', '2', '3', '4'};
+   static const uint8_t binary[] = {'1', '2', '3', '4'};
    bson_t *b;
    bson_t *b2;
 

src/libbson/tests/test-decimal128.c

@@ -37,7 +37,7 @@
    do {                                 \
       (dec).high = (h);                 \
       (dec).low = (l);                  \
-   } while (0);
+   } while (0)
 
 
 static void

src/libbson/tests/test-iso8601.c

@@ -3,7 +3,7 @@
 #include "bson/bson-iso8601-private.h"
 #include "TestSuite.h"
 
-#define IS_TIME_T_SMALL (sizeof (time_t) == sizeof (int32_t))
+static const bool is_time_t_small = (sizeof (time_t) == sizeof (int32_t));
 
 static void
 test_date (const char *str, int64_t millis)
@@ -91,7 +91,7 @@ test_bson_iso8601_utc (void)
    test_date_rt ("1970-06-30T01:06:40.981Z", 15556000981ULL);
    test_date ("1970-01-01T00:00:00.000+0100", -3600LL * 1000);
 
-   if (!IS_TIME_T_SMALL) {
+   if (!is_time_t_small) {
       test_date_rt ("2058-02-20T18:29:11.100Z", 2781455351100ULL);
       test_date ("3001-01-01T08:00:00.000Z", 32535244800000ULL);
    }
@@ -134,7 +134,7 @@ test_bson_iso8601_local (void)
                  15556000981ULL);
    test_date_io ("1969-12-31T16:00:00.000-0800", "1970-01-01T00:00:00Z", 0ULL);
 
-   if (!IS_TIME_T_SMALL) {
+   if (!is_time_t_small) {
       test_date_io ("2058-02-20T13:29:11.100-0500",
                     "2058-02-20T18:29:11.100Z",
                     2781455351100ULL);
@@ -291,7 +291,7 @@ test_bson_iso8601_leap_year (void)
    test_date_rt ("2032-02-29T00:00:00Z", 1961625600000ULL);
    test_date_rt ("2036-02-29T00:00:00Z", 2087856000000ULL);
 
-   if (!IS_TIME_T_SMALL) {
+   if (!is_time_t_small) {
       test_date_rt ("2040-02-29T00:00:00Z", 2214086400000ULL);
       test_date_rt ("2044-02-29T00:00:00Z", 2340316800000ULL);
       test_date_rt ("2048-02-29T00:00:00Z", 2466547200000ULL);

src/libbson/tests/test-json.c

@@ -2951,7 +2951,7 @@ _test_json_produces_multiple (const char *json_in, int err_expected, ...)
 }
 
 #define TEST_JSON_PRODUCES_MULTIPLE(_json, _has_err, ...) \
-   _test_json_produces_multiple (_json, _has_err, __VA_ARGS__, NULL);
+   _test_json_produces_multiple (_json, _has_err, __VA_ARGS__, NULL)
 
 static void
 test_bson_as_json_multi_object (void)

src/libmongoc/examples/basic_aggregation/map-reduce-basic.c

@@ -2,16 +2,14 @@ bool
 map_reduce_basic (mongoc_database_t *database)
 {
    bson_t reply;
-   bson_t *command;
-   bool res;
+   bool res = false;
    bson_error_t error;
-   mongoc_cursor_t *cursor;
-   const bson_t *doc;
+   mongoc_cursor_t *cursor = NULL;
 
    bool query_done = false;
 
    const char *out_collection_name = "outCollection";
-   mongoc_collection_t *out_collection;
+   mongoc_collection_t *out_collection = NULL;
 
    /* Empty find query */
    bson_t find_query = BSON_INITIALIZER;
@@ -20,14 +18,14 @@ map_reduce_basic (mongoc_database_t *database)
 
    /* Other arguments can also be specified here, like "query" or
       "limit" and so on */
-   command = BCON_NEW ("mapReduce",
-                       BCON_UTF8 (COLLECTION_NAME),
-                       "map",
-                       BCON_CODE (MAPPER),
-                       "reduce",
-                       BCON_CODE (REDUCER),
-                       "out",
-                       BCON_UTF8 (out_collection_name));
+   bson_t *const command = BCON_NEW ("mapReduce",
+                                     BCON_UTF8 (COLLECTION_NAME),
+                                     "map",
+                                     BCON_CODE (MAPPER),
+                                     "reduce",
+                                     BCON_CODE (REDUCER),
+                                     "out",
+                                     BCON_UTF8 (out_collection_name));
    res =
       mongoc_database_command_simple (database, command, NULL, &reply, &error);
 
@@ -47,6 +45,7 @@ map_reduce_basic (mongoc_database_t *database)
    query_done = true;
 
    /* Do something with the results */
+   const bson_t *doc = NULL;
    while (mongoc_cursor_next (cursor, &doc)) {
       print_res (doc);
    }