r9008@Kushana: nickm | 2006-09-29 13:50:10 -0400

 Doxygen comments for code in common.  Also simplify a few code paths to be more clear/speedy/correct.


svn:r8536

5 files changed, 128 insertions, 26 deletions

diff --git a/src/common/container.c b/src/common/container.c
index 64ad42063..170fe59e2 100644
--- a/src/common/container.c
+++ b/src/common/container.c
@@ -493,10 +493,23 @@ smartlist_uniq_strings(smartlist_t *sl)
   smartlist_uniq(sl, _compare_string_ptrs, NULL);
 }
 
-#define LEFT_CHILD(i)  ( ((i)+1)*2 - 1)
-#define RIGHT_CHILD(i) ( ((i)+1)*2 )
-#define PARENT(i)      ( ((i)+1)/2 - 1)
+/* Heap-based priority queue implementation for O(lg N) insert and remove.
+ * Recall that the heap property is that, for every index I, h[I] <
+ * H[LEFT_CHILD[I]] and h[I] < H[RIGHT_CHILD[I]].
+ */
 
+/* For a 1-indexed array, we would use LEFT_CHILD[x] = 2*x and RIGHT_CHILD[x]
+ * = 2*x + 1.  But this is C, so we have to adjust a little. */
+//#define LEFT_CHILD(i)  ( ((i)+1)*2 - 1)
+//#define RIGHT_CHILD(i) ( ((i)+1)*2 )
+//#define PARENT(i)      ( ((i)+1)/2 - 1)
+#define LEFT_CHILD(i)  ( 2*(i) + 1 )
+#define RIGHT_CHILD(i) ( 2*(i) + 2 )
+#define PARENT(i)      ( ((i)-1) / 2 )
+
+/** Helper. <b>sl</b> may have at most one violation of the heap property:
+ * the item at <b>idx</b> may be greater than one or both of its children.
+ * Restore the heap property. */
 static INLINE void
 smartlist_heapify(smartlist_t *sl,
                   int (*compare)(const void *a, const void *b),
@@ -528,6 +541,8 @@ smartlist_heapify(smartlist_t *sl,
   }
 }
 
+/** Insert <b>item</b> into the heap stored in <b>sl</b>, where order
+ * is determined by <b>compare</b> */
 void
 smartlist_pqueue_add(smartlist_t *sl,
                      int (*compare)(const void *a, const void *b),
@@ -549,6 +564,9 @@ smartlist_pqueue_add(smartlist_t *sl,
   }
 }
 
+/** Remove and return the top-priority item from the heap stored in <b>sl</b>,
+ * where order is determined by <b>compare</b>.  <b>sl</b> must not be
+ * empty. */
 void *
 smartlist_pqueue_pop(smartlist_t *sl,
                      int (*compare)(const void *a, const void *b))
@@ -564,6 +582,8 @@ smartlist_pqueue_pop(smartlist_t *sl,
   return top;
 }
 
+/** Assert that the heap property is correctly maintained by the heap stored
+ * in <b>sl</b>, where order is determined by <b>compare</b>. */
 void
 smartlist_pqueue_assert_ok(smartlist_t *sl,
                            int (*compare)(const void *a, const void *b))
@@ -609,13 +629,14 @@ smartlist_uniq_digests(smartlist_t *sl)
 DEFINE_MAP_STRUCTS(strmap_t, char *key, strmap_);
 DEFINE_MAP_STRUCTS(digestmap_t, char key[DIGEST_LEN], digestmap_);
 
-/** Helper: compare strmap_t_entry objects by key value. */
+/** Helper: compare strmap_entry_t objects by key value. */
 static INLINE int
 strmap_entries_eq(strmap_entry_t *a, strmap_entry_t *b)
 {
   return !strcmp(a->key, b->key);
 }
 
+/** Helper: return a hash value for a strmap_entry_t */
 static INLINE unsigned int
 strmap_entry_hash(strmap_entry_t *a)
 {
@@ -629,6 +650,7 @@ digestmap_entries_eq(digestmap_entry_t *a, digestmap_entry_t *b)
   return !memcmp(a->key, b->key, DIGEST_LEN);
 }
 
+/** Helper: return a hash value for a digest_map_t */
 static INLINE unsigned int
 digestmap_entry_hash(digestmap_entry_t *a)
 {
@@ -1029,6 +1051,7 @@ digestmap_isempty(digestmap_t *map)
   return HT_EMPTY(&map->head);
 }
 
+/** Return the number of items in <b>map</b> */
 int
 strmap_size(strmap_t *map)
 {
diff --git a/src/common/crypto.c b/src/common/crypto.c
index 57b504f5b..c7fea55eb 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -77,7 +77,9 @@ const char crypto_c_id[] =
 #define PRIVATE_KEY_OK(k) ((k) && (k)->key && (k)->key->p)
 
 #ifdef TOR_IS_MULTITHREADED
+/** A number of prealloced mutexes for use by openssl. */
 static tor_mutex_t **_openssl_mutexes = NULL;
+/** How many mutexes have we allocated for use by openssl? */
 static int _n_openssl_mutexes = -1;
 #endif
 
@@ -164,6 +166,7 @@ crypto_log_errors(int severity, const char *doing)
 }
 
 #ifndef NO_ENGINES
+/** Log any OpenSSL engines we're using at NOTICE. */
 static void
 log_engine(const char *fn, ENGINE *e)
 {
@@ -1711,6 +1714,9 @@ base64_decode(char *dest, size_t destlen, const char *src, size_t srclen)
   return ret;
 }
 
+/** Base-64 encode DIGEST_LINE bytes from <b>digest</b>, remove the trailing =
+ * and newline characters, and store the nul-terminated result in the first
+ * BASE64_DIGEST_LEN+1 bytes of <b>d64</b>.  */
 int
 digest_to_base64(char *d64, const char *digest)
 {
@@ -1721,6 +1727,9 @@ digest_to_base64(char *d64, const char *digest)
   return 0;
 }
 
+/** Given a base-64 encoded, nul-terminated digest in <b>d64</b> (without
+ * trailing newline or = characters), decode it and store the result in the
+ * first DIGEST_LEN bytes at <b>digest</b>. */
 int
 digest_from_base64(char *digest, const char *d64)
 {
@@ -1803,6 +1812,7 @@ secret_to_key(char *key_out, size_t key_out_len, const char *secret,
 }
 
 #ifdef TOR_IS_MULTITHREADED
+/** Helper: openssl uses this callback to manipulate mutexes. */
 static void
 _openssl_locking_cb(int mode, int n, const char *file, int line)
 {
@@ -1819,6 +1829,8 @@ _openssl_locking_cb(int mode, int n, const char *file, int line)
     tor_mutex_release(_openssl_mutexes[n]);
 }
 
+/** Helper: Construct mutexes, and set callbacks to help OpenSSL handle being
+ * multithreaded. */
 static int
 setup_openssl_threading(void)
 {
diff --git a/src/common/log.c b/src/common/log.c
index d6c5699f2..945d45e9d 100644
--- a/src/common/log.c
+++ b/src/common/log.c
@@ -60,8 +60,7 @@ sev_to_string(int severity)
   }
 }
 
-/** Helper: decide whether to include the function name in the log message.
- * */
+/** Helper: decide whether to include the function name in the log message. */
 static INLINE int
 should_log_function_name(uint32_t domain, int severity)
 {
@@ -434,6 +433,8 @@ add_callback_log(int loglevelMin, int loglevelMax, log_callback cb)
   return 0;
 }
 
+/** Adjust the configured severity of any logs whose callback function is
+ * <b>cb</b>. */
 void
 change_callback_log_severity(int loglevelMin, int loglevelMax,
                              log_callback cb)
@@ -577,7 +578,10 @@ switch_logs_debug(void)
 }
 
 #ifdef HAVE_EVENT_SET_LOG_CALLBACK
+/** A string which, if it appears in a libevent log, should be ignored. */
 static const char *suppress_msg = NULL;
+/** Callback function passed to event_set_log() so we can intercept
+ * log messages from libevent. */
 static void
 libevent_logging_callback(int severity, const char *msg)
 {
@@ -608,11 +612,13 @@ libevent_logging_callback(int severity, const char *msg)
       break;
   }
 }
+/** Set hook to intercept log messages from libevent. */
 void
 configure_libevent_logging(void)
 {
   event_set_log_callback(libevent_logging_callback);
 }
+/** Ignore any libevent log message that contains <b>msg</b> */
 void
 suppress_libevent_log_msg(const char *msg)
 {
diff --git a/src/common/torgzip.c b/src/common/torgzip.c
index ec0287077..1d1fdc848 100644
--- a/src/common/torgzip.c
+++ b/src/common/torgzip.c
@@ -29,6 +29,8 @@ const char torgzip_c_id[] =
 #include "log.h"
 #include "torgzip.h"
 
+/** Set to 1 if zlib is a version that supports gzip; set to 0 if it doesn't;
+ * set to -1 if we haven't checked yet. */
 static int gzip_is_supported = -1;
 
 /** Return true iff we support gzip-based compression.  Otherwise, we need to
@@ -49,6 +51,7 @@ is_gzip_supported(void)
   return gzip_is_supported;
 }
 
+/** Return the 'bits' value to tell zlib to use <b>method</b>.*/
 static INLINE int
 method_bits(compress_method_t method)
 {
@@ -152,6 +155,10 @@ tor_gzip_compress(char **out, size_t *out_len,
  * buffer, using the method described in <b>method</b>.  Store the uncompressed
  * string in *<b>out</b>, and its length in *<b>out_len</b>.  Return 0 on
  * success, -1 on failure.
+ *
+ * If <b>complete_only</b> is true, we consider a truncated input as a
+ * failure; otherwise we decompress as much as we can.  Warn about truncated
+ * or corrupt inputs at <b>protocol_warn_level</b>.
  */
 int
 tor_gzip_uncompress(char **out, size_t *out_len,
@@ -287,7 +294,9 @@ struct tor_zlib_state_t {
   int compress;
 };
 
-/** DOCDOC */
+/** Construct and return a tor_zlib_state_t object using <b>method</b>.  If
+ * <b>compress</b>, it's for compression; otherwise it's for
+ * decompression.  */
 tor_zlib_state_t *
 tor_zlib_new(int compress, compress_method_t method)
 {
@@ -319,7 +328,16 @@ tor_zlib_new(int compress, compress_method_t method)
  return NULL;
 }
 
-/** DOCDOC */
+/** Compress/decommpress some bytes using <b>state</b>.  Read up to
+ * *<b>in_len</b> bytes from *<b>in</b>, and write up to *<b>out_len</b> bytes
+ * to *<b>out</b>, adjusting the values as we go.  If <b>finish</b> is true,
+ * we've reached the end of the input.
+ *
+ * Return TOR_ZLIB_DONE if we've finished the entire compression/decompression.
+ * Return TOR_ZLIB_OK if we're processed everything from the input.
+ * Return TOR_ZLIB_BUF_FULL if we're out of space on <b>out</b>.
+ * Return TOR_ZLIB_ERR if the stream is corrupt.
+ */
 tor_zlib_output_t
 tor_zlib_process(tor_zlib_state_t *state,
                  char **out, size_t *out_len,
@@ -349,7 +367,7 @@ tor_zlib_process(tor_zlib_state_t *state,
       return TOR_ZLIB_DONE;
     case Z_BUF_ERROR:
       if (state->stream.avail_in == 0)
-        return Z_OK;
+        return TOR_ZLIB_OK;
       return TOR_ZLIB_BUF_FULL;
     case Z_OK:
       if (state->stream.avail_out == 0 || finish)
@@ -362,7 +380,7 @@ tor_zlib_process(tor_zlib_state_t *state,
     }
 }
 
-/** DOCDOC */
+/** Deallocate <b>state</b>. */
 void
 tor_zlib_free(tor_zlib_state_t *state)
 {
diff --git a/src/common/util.c b/src/common/util.c
index 6c6ce088c..59be5ebb7 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -493,6 +493,8 @@ tor_digest_is_zero(const char *digest)
   return tor_mem_is_zero(digest, DIGEST_LEN);
 }
 
+/* Helper: common code to check whether the result of a strtol or strtoul or
+ * strtoll is correct. */
 #define CHECK_STRTOX_RESULT()                           \
   /* Was at least one character converted? */           \
   if (endptr == s)                                      \
@@ -530,6 +532,7 @@ tor_parse_long(const char *s, int base, long min, long max,
   CHECK_STRTOX_RESULT();
 }
 
+/** As tor_parse_log, but return an unsigned long */
 unsigned long
 tor_parse_ulong(const char *s, int base, unsigned long min,
                 unsigned long max, int *ok, char **next)
@@ -541,7 +544,8 @@ tor_parse_ulong(const char *s, int base, unsigned long min,
   CHECK_STRTOX_RESULT();
 }
 
-/** Only base 10 is guaranteed to work for now. */
+/** As tor_parse_log, but return a unit64_t.  Only base 10 is guaranteed to
+ * work for now. */
 uint64_t
 tor_parse_uint64(const char *s, int base, uint64_t min,
                  uint64_t max, int *ok, char **next)
@@ -570,6 +574,10 @@ tor_parse_uint64(const char *s, int base, uint64_t min,
   CHECK_STRTOX_RESULT();
 }
 
+/** Encode the <b>srclen</b> bytes at <b>src</b> in a NUL-terminated,
+ * uppercase hexadecimal string; store it in the <b>destlen</b>-byte buffer
+ * <b>dest</b>.
+ */
 void
 base16_encode(char *dest, size_t destlen, const char *src, size_t srclen)
 {
@@ -589,23 +597,35 @@ base16_encode(char *dest, size_t destlen, const char *src, size_t srclen)
   *cp = '\0';
 }
 
-static const char HEX_DIGITS[] = "0123456789ABCDEFabcdef";
-
+/** Helper: given a hex digit, return its value, or -1 if it isn't hex. */
 static INLINE int
 hex_decode_digit(char c)
 {
-  const char *cp;
-  int n;
-  cp = strchr(HEX_DIGITS, c);
-  if (!cp)
-    return -1;
-  n = cp-HEX_DIGITS;
-  if (n<=15)
-    return n; /* digit or uppercase */
-  else
-    return n-6; /* lowercase */
+  switch (c) {
+    case '0': return 0;
+    case '1': return 1;
+    case '2': return 2;
+    case '3': return 3;
+    case '4': return 4;
+    case '5': return 5;
+    case '6': return 6;
+    case '7': return 7;
+    case '8': return 8;
+    case '9': return 9;
+    case 'A': case 'a': return 10;
+    case 'B': case 'b': return 11;
+    case 'C': case 'c': return 12;
+    case 'D': case 'd': return 13;
+    case 'E': case 'e': return 14;
+    case 'F': case 'f': return 15;
+    default:
+      return -1;
+  }
 }
 
+/** Given a hexadecimal string of <b>srclen</b> bytes in <b>src/b>, decode it
+ * and store the result in the <b>destlen</b>-byte buffer at <b>dest</b>.
+ * Return 0 on success, -1 on failure. */
 int
 base16_decode(char *dest, size_t destlen, const char *src, size_t srclen)
 {
@@ -832,6 +852,11 @@ static const char *MONTH_NAMES[] =
   { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
 
+/** Set <b>buf</b> to the RFC1123 encoding of the GMT value of <b>t</b>.
+ * The buffer must be at least RFC1123_TIME_LEN+1 bytes long.
+ *
+ * (RFC1123 format is Fri, 29 Sep 2006 15:54:20 GMT)
+ */
 void
 format_rfc1123_time(char *buf, time_t t)
 {
@@ -848,6 +873,11 @@ format_rfc1123_time(char *buf, time_t t)
   memcpy(buf+8, MONTH_NAMES[tm.tm_mon], 3);
 }
 
+/** Parse the the RFC1123 encoding of some time (in GMT) from <b>buf</b>,
+ * and store the result in *<b>t</b>.
+ *
+ * Return 0 on succcess, -1 on failure.
+*/
 int
 parse_rfc1123_time(const char *buf, time_t *t)
 {
@@ -896,6 +926,11 @@ parse_rfc1123_time(const char *buf, time_t *t)
   return 0;
 }
 
+/** Set <b>buf</b> to the ISO???? encoding of the local value of <b>t</b>.
+ * The buffer must be at least ISO_TIME_LEN+1 bytes long.
+ *
+ * (ISO???? format is 2006-10-29 10:57:20)
+ */
 void
 format_local_iso_time(char *buf, time_t t)
 {
@@ -903,6 +938,9 @@ format_local_iso_time(char *buf, time_t t)
   strftime(buf, ISO_TIME_LEN+1, "%Y-%m-%d %H:%M:%S", tor_localtime_r(&t, &tm));
 }
 
+/** Set <b>buf</b> to the ISO???? encoding of the GMT value of <b>t</b>.
+ * The buffer must be at least ISO_TIME_LEN+1 bytes long.
+ */
 void
 format_iso_time(char *buf, time_t t)
 {
@@ -1149,7 +1187,10 @@ write_str_to_file(const char *fname, const char *str, int bin)
   return write_bytes_to_file(fname, str, strlen(str), bin);
 }
 
-/* DOCDOC */
+/** Helper: given a set of flags as passed to open(2), open the file
+ * <b>fname</b> and write all the sized_chunk_t structs in <b>chunks</t> to
+ * the file.  Do so as atomically as possible e.g. by opening temp files and
+ * renaming. */
 static int
 write_chunks_to_file_impl(const char *fname, const smartlist_t *chunks,
                           int open_flags)
@@ -1204,7 +1245,8 @@ write_chunks_to_file_impl(const char *fname, const smartlist_t *chunks,
   return -1;
 }
 
-/* DOCDOC */
+/* Given a smartlist of sized_chunk_t, write them atomically to a file
+ * <b>fname</b>, overwriting or creating the file as necessary.  */
 int
 write_chunks_to_file(const char *fname, const smartlist_t *chunks, int bin)
 {
@@ -1228,7 +1270,8 @@ write_bytes_to_file(const char *fname, const char *str, size_t len,
   return r;
 }
 
-/* DOCDOC */
+/** As write_bytes_to_file, but if the file already exists, append the bytes
+ * to the end of the file instead of overwriting it. */
 int
 append_bytes_to_file(const char *fname, const char *str, size_t len,
                      int bin)