Add some more tests, prepping for asset testing

src/dusk/asset/asset.c

@@ -184,6 +184,7 @@ errorret_t assetUpdate(void) {
             loading->entry->state == ASSET_ENTRY_STATE_ERROR,
             "Loader did not set entry state to error on failed load."
           );
+          errorCatch(errorPrint(ret));
         }
 
         threadMutexUnlock(&loading->mutex);

src/dusk/asset/loader/locale/assetlocaleloader.c

@@ -303,16 +303,24 @@ errorret_t assetLocaleLineSkipBlanks(
   while(!reader->eof) {
     // Skip blank lines
     if(lineBuffer[0] == '\0') {
-      errorChain(assetFileLineReaderNext(reader));
+      errorret_t r = assetFileLineReaderNext(reader);
+      if(errorIsNotOk(r)) {
+        errorCatch(r);
+        break;
+      }
       continue;
     }
 
     // Skip comment lines
     if(lineBuffer[0] == '#') {
-      errorChain(assetFileLineReaderNext(reader));
+      errorret_t r = assetFileLineReaderNext(reader);
+      if(errorIsNotOk(r)) {
+        errorCatch(r);
+        break;
+      }
       continue;
     }
-    
+
     // Is line only spaces?
     size_t lineLength = strlen((char_t *)lineBuffer);
     size_t i;
@@ -325,7 +333,11 @@ errorret_t assetLocaleLineSkipBlanks(
     }
 
     if(onlySpaces) {
-      errorChain(assetFileLineReaderNext(reader));
+      errorret_t r = assetFileLineReaderNext(reader);
+      if(errorIsNotOk(r)) {
+        errorCatch(r);
+        break;
+      }
       continue;
     }
     break;
@@ -361,10 +373,18 @@ errorret_t assetLocaleLineUnbuffer(
 
   // Now start buffering lines out
   while(!reader->eof) {
-    errorChain(assetFileLineReaderNext(reader));
+    errorret_t r = assetFileLineReaderNext(reader);
+    if(errorIsNotOk(r)) {
+      errorCatch(r);
+      break;
+    }
 
     // Skip blank lines
-    errorChain(assetLocaleLineSkipBlanks(reader, lineBuffer));
+    r = assetLocaleLineSkipBlanks(reader, lineBuffer);
+    if(errorIsNotOk(r)) {
+      errorCatch(r);
+      break;
+    }
     
     // Skip starting spaces
     char_t *ptr = (char_t *)lineBuffer;

src/dusk/asset/loader/locale/assetlocaleloader.h

@@ -1,6 +1,6 @@
 /**
  * Copyright (c) 2026 Dominic Masters
- * 
+ *
  * This software is released under the MIT License.
  * https://opensource.org/licenses/MIT
  */
@@ -11,11 +11,22 @@
 typedef struct assetloading_s assetloading_t;
 typedef struct assetentry_s assetentry_t;
 
+/** Input passed to the locale loader — currently unused. */
 typedef struct { void *nothing; } assetlocaleloaderinput_t;
+
+/** Per-slot scratch data used while the locale file is loading. */
 typedef struct { void *nothing; } assetlocaleloaderloading_t;
 
+/** Maximum number of distinct plural forms a locale file may declare. */
 #define ASSET_LOCALE_FILE_PLURAL_FORM_COUNT 6
 
+/**
+ * Comparison operator used in a plural-form expression.
+ *
+ * Each condition in the plural-form header is evaluated as
+ *   `n <op> value`
+ * where `n` is the runtime plural count.
+ */
 typedef enum {
   ASSET_LOCALE_PLURAL_OP_EQUAL,
   ASSET_LOCALE_PLURAL_OP_NOT_EQUAL,
@@ -25,13 +36,24 @@ typedef enum {
   ASSET_LOCALE_PLURAL_OP_GREATER_EQUAL
 } assetlocalepluraloperation_t;
 
+/**
+ * Discriminator tag for a locale string argument.
+ * @see assetlocalearg_t
+ */
 typedef enum {
   ASSET_LOCALE_ARG_STRING,
   ASSET_LOCALE_ARG_INT,
   ASSET_LOCALE_ARG_FLOAT
 } assetlocaleargtype_t;
 
+/**
+ * A single typed argument for locale string substitution.
+ *
+ * Used with @ref assetLocaleGetStringWithArgs to fill `%s`, `%d`, or `%f`
+ * placeholders inside a translated string.
+ */
 typedef struct {
+  /** Which union member is active. */
   assetlocaleargtype_t type;
   union {
     const char_t *stringValue;
@@ -40,20 +62,72 @@ typedef struct {
   };
 } assetlocalearg_t;
 
+/**
+ * Runtime state for an open locale file.
+ *
+ * Loaded once by @ref assetLocaleLoaderSync and kept alive for the lifetime
+ * of the asset entry. The plural-form fields are populated from the PO header
+ * by @ref assetLocaleParseHeader.
+ *
+ * Plural evaluation works as a linear scan over `pluralStateCount - 1`
+ * conditions; if none match, `pluralDefaultIndex` is returned.
+ */
 typedef struct {
+  /** Underlying file handle used to rewind and re-read the PO data. */
   assetfile_t file;
+
+  /** Comparison operator for each conditional plural clause. */
   assetlocalepluraloperation_t pluralOps[ASSET_LOCALE_FILE_PLURAL_FORM_COUNT];
+
+  /** Right-hand value for each conditional plural clause. */
   int32_t pluralValues[ASSET_LOCALE_FILE_PLURAL_FORM_COUNT];
+
+  /** Form index returned when the corresponding condition is true. */
   int32_t pluralIndices[ASSET_LOCALE_FILE_PLURAL_FORM_COUNT];
+
+  /** Total number of plural forms declared by `nplurals=`. */
   uint8_t pluralStateCount;
+
+  /** Form index used when no conditional clause matches. */
   uint8_t pluralDefaultIndex;
 } assetlocalefile_t;
 
+/** Convenience alias — the loaded output type of a locale asset entry. */
 typedef assetlocalefile_t assetlocaleoutput_t;
 
+/**
+ * Synchronous loader callback. Opens and validates the locale file, reads the
+ * PO header, and parses plural-form rules. Sets entry state to
+ * `ASSET_ENTRY_STATE_LOADED` on success or `ASSET_ENTRY_STATE_ERROR` on
+ * failure.
+ *
+ * @param loading The loading slot for this asset entry.
+ * @return OK on success, error otherwise.
+ */
 errorret_t assetLocaleLoaderSync(assetloading_t *loading);
+
+/**
+ * Dispose callback. Closes the open file handle and zeros the locale data.
+ *
+ * @param entry The asset entry to dispose.
+ * @return OK on success, error otherwise.
+ */
 errorret_t assetLocaleDispose(assetentry_t *entry);
 
+/**
+ * Parses the `Plural-Forms:` line from a PO header string and populates the
+ * plural-form fields of `localeFile`. If no `Plural-Forms:` key is present
+ * the function returns OK without modifying the struct.
+ *
+ * Supports the `nplurals=N; plural=(<expr>);` syntax where `<expr>` is a
+ * chain of `n <op> value ? index : ...` ternary conditions ending with a
+ * fallback index.
+ *
+ * @param localeFile  Struct whose plural fields will be filled in.
+ * @param headerBuffer  The raw PO header string (msgstr of msgid "").
+ * @param headerBufferSize  Size of `headerBuffer` in bytes.
+ * @return OK on success, error if the plural expression is malformed.
+ */
 errorret_t assetLocaleParseHeader(
   assetlocalefile_t *localeFile,
   char_t *headerBuffer,
@@ -61,11 +135,29 @@ errorret_t assetLocaleParseHeader(
 );
 
 /**
- * Skips blank lines and comment lines in the line reader.
- * 
- * @param reader Line reader to read from.
- * @param lineBuffer Buffer to use for reading lines.
- * @return Any error that occurs during skipping.
+ * Evaluates which plural form index to use for a given count.
+ *
+ * Walks the conditions stored in `file` in order; returns the index for the
+ * first condition that matches `pluralCount`. Falls back to
+ * `file->pluralDefaultIndex` if none match.
+ *
+ * @param file  Locale file with parsed plural rules.
+ * @param pluralCount  The runtime count (e.g. number of items).
+ * @return Zero-based plural form index.
+ */
+uint8_t assetLocaleEvaluatePlural(
+  assetlocalefile_t *file,
+  const int32_t pluralCount
+);
+
+/**
+ * Advances the line reader past blank lines, comment lines (starting with
+ * `#`), and lines containing only spaces. Stops at the first content line or
+ * end of file.
+ *
+ * @param reader  Line reader positioned at the current line.
+ * @param lineBuffer  Output buffer that the reader writes each line into.
+ * @return OK on success, error if reading fails.
  */
 errorret_t assetLocaleLineSkipBlanks(
   assetfilelinereader_t *reader,
@@ -73,16 +165,19 @@ errorret_t assetLocaleLineSkipBlanks(
 );
 
 /**
- * Unbuffers a potentially multi-line quoted string from the line reader.
- * 
- * This will read lines until it finds a line that starts with a quote, then
- * read until the closing quote.
- * 
- * @param reader Line reader to read from.
- * @param lineBuffer Buffer to use for reading lines.
- * @param stringBuffer Buffer to write the unbuffered string to.
- * @param stringBufferSize Size of the string buffer.
- * @return Any error that occurs during unbuffering.
+ * Reads a PO quoted string value from the current line and any immediately
+ * following continuation lines that begin with `"`.
+ *
+ * Handles standard C escape sequences (`\n`, `\t`, `\\`, `\"`).
+ *
+ * @param reader  Line reader positioned at the line containing the opening
+ *                quote (e.g. `msgstr "..."`).
+ * @param lineBuffer  Buffer the reader fills on each @ref assetFileLineReaderNext
+ *                    call; also used to detect continuation lines.
+ * @param stringBuffer  Destination for the unescaped string content.
+ * @param stringBufferSize  Capacity of `stringBuffer` in bytes.
+ * @return OK on success, error if a quote or escape sequence is malformed or
+ *         the buffer would overflow.
  */
 errorret_t assetLocaleLineUnbuffer(
   assetfilelinereader_t *reader,
@@ -92,14 +187,19 @@ errorret_t assetLocaleLineUnbuffer(
 );
 
 /**
- * Test function for locale asset loading.
- * 
- * @param file Asset file to test loading from.
- * @param messageId The message ID to retrieve.
- * @param pluralCount Count for formulating the plural variant.
- * @param stringBuffer Buffer to write the retrieved string to.
- * @param stringBufferSize Size of the string buffer.
- * @return Any error that occurs during testing.
+ * Looks up a translated string by message ID from the open locale file.
+ *
+ * Rewinds the file and scans from the beginning on every call. For plural
+ * entries (`msgid_plural`) the `pluralCount` is evaluated against the loaded
+ * plural rules to select the correct `msgstr[N]` form.
+ *
+ * @param file  Locale file to search. Must be open.
+ * @param messageId  PO message ID to find (`""` retrieves the header entry).
+ * @param pluralCount  Count used to select the plural form (ignored for
+ *                     singular entries).
+ * @param stringBuffer  Buffer to receive the translated string.
+ * @param stringBufferSize  Capacity of `stringBuffer` in bytes.
+ * @return OK on success, error if the message ID is not found or I/O fails.
  */
 errorret_t assetLocaleGetString(
   assetlocalefile_t *file,
@@ -110,15 +210,21 @@ errorret_t assetLocaleGetString(
 );
 
 /**
- * Test function for locale asset loading with a variable argument list.
- * 
- * @param file Asset file to test loading from.
- * @param messageId The message ID to retrieve.
- * @param pluralCount Count for formulating the plural variant.
- * @param buffer Buffer to write the retrieved string to.
- * @param bufferSize Size of the buffer.
- * @param ... Additional arguments for formatting the string.
- * @return Any error that occurs during testing.
+ * Looks up a translated string and formats it with a `printf`-style variadic
+ * argument list.
+ *
+ * Retrieves the raw format string via @ref assetLocaleGetString then applies
+ * `vsnprintf` with the provided arguments.
+ *
+ * @param file  Locale file to search. Must be open.
+ * @param messageId  PO message ID to find.
+ * @param pluralCount  Count used to select the plural form.
+ * @param buffer  Buffer to receive the formatted string.
+ * @param bufferSize  Capacity of `buffer` in bytes.
+ * @param ...  Format arguments matching the specifiers in the translated
+ *             string.
+ * @return OK on success, error if the message is not found or formatting
+ *         fails.
  */
 errorret_t assetLocaleGetStringWithVA(
   assetlocalefile_t *file,
@@ -130,16 +236,22 @@ errorret_t assetLocaleGetStringWithVA(
 );
 
 /**
- * Test function for locale asset loading with a list of arguments.
- * 
- * @param file Asset file to test loading from.
- * @param messageId The message ID to retrieve.
- * @param pluralCount Count for formulating the plural variant.
- * @param buffer Buffer to write the retrieved string to.
- * @param bufferSize Size of the buffer.
- * @param args List of arguments for formatting the string.
- * @param argCount Number of arguments in the list.
- * @return Any error that occurs during testing.
+ * Looks up a translated string and substitutes typed arguments into its
+ * `%s`, `%d`, and `%f` placeholders.
+ *
+ * Unlike @ref assetLocaleGetStringWithVA this variant accepts an explicit
+ * array of @ref assetlocalearg_t values, which is safer to use from
+ * generated or scripted call sites.
+ *
+ * @param file  Locale file to search. Must be open.
+ * @param messageId  PO message ID to find.
+ * @param pluralCount  Count used to select the plural form.
+ * @param buffer  Buffer to receive the formatted string.
+ * @param bufferSize  Capacity of `buffer` in bytes.
+ * @param args  Array of typed arguments; may be NULL when `argCount` is 0.
+ * @param argCount  Number of elements in `args`.
+ * @return OK on success, error if the message is not found, an argument type
+ *         mismatches the specifier, or the buffer would overflow.
  */
 errorret_t assetLocaleGetStringWithArgs(
   assetlocalefile_t *file,
@@ -149,4 +261,4 @@ errorret_t assetLocaleGetStringWithArgs(
   const size_t bufferSize,
   const assetlocalearg_t *args,
   const size_t argCount
-);
+);