i18n data is kept in and generated from JSON files

Introduced a new resource compiler script kiwix-compile-i18n that
processes i18n string data stored in JSON files and generates sorted C++
tables of string keys and values for all languages.

scripts/kiwix-compile-i18n

@@ -0,0 +1,167 @@
+#!/usr/bin/env python3
+
+'''
+Copyright 2022 Veloman Yunkan <veloman.yunkan@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3 of the License, or any
+later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA.
+'''
+
+import argparse
+import os.path
+import re
+import json
+
+def to_identifier(name):
+    ident = re.sub(r'[^0-9a-zA-Z]', '_', name)
+    if ident[0].isnumeric():
+        return "_"+ident
+    return ident
+
+def lang_code(filename):
+    filename = os.path.basename(filename)
+    lang = to_identifier(os.path.splitext(filename)[0])
+    print(filename, '->', lang)
+    return lang
+
+# In CXX code templates, fragments that must be replaced are marked up with
+# $< and >$, while curly braces (as significant part of C++ syntax) are not
+# artificially doubled. The CXX code template is converted into a form usable
+# by Python's str.format() via 4 simple replace() operations
+def expand_cxx_template(t, **kwargs):
+    fmt = t.replace('{', '{{') \
+           .replace('}', '}}') \
+           .replace('$<', '{') \
+           .replace('>$', '}')
+    return fmt.format(**kwargs)
+
+def cxx_string_literal(s):
+    # Taking advantage of the fact the JSON string escape rules match
+    # those of C++
+    return 'u8' + json.dumps(s)
+
+string_table_cxx_template = '''
+const I18nString $<TABLE_NAME>$[] = {
+  $<TABLE_ENTRIES>$
+};
+'''
+
+lang_table_entry_cxx_template = '''
+    {
+        $<LANG_STRING_LITERAL>$,
+        ARRAY_ELEMENT_COUNT($<STRING_TABLE_NAME>$),
+        $<STRING_TABLE_NAME>$
+    }'''
+
+cxxfile_template = '''// This file is automatically generated. Do not modify it.
+
+#include "server/i18n.h"
+
+namespace kiwix {
+namespace i18n {
+
+namespace
+{
+
+$<STRING_DATA>$
+
+} // unnamed namespace
+
+#define ARRAY_ELEMENT_COUNT(a) (sizeof(a)/sizeof(a[0]))
+
+extern const I18nStringTable stringTables[] = {
+  $<LANG_TABLE>$
+};
+
+extern const size_t langCount = $<LANG_COUNT>$;
+
+} // namespace i18n
+} // namespace kiwix
+'''
+
+class Resource:
+    def __init__(self, base_dirs, filename):
+        filename = filename.strip()
+        self.filename = filename
+        self.lang_code = lang_code(filename)
+        found = False
+        for base_dir in base_dirs:
+            try:
+                with open(os.path.join(base_dir, filename), 'r') as f:
+                    self.data = f.read()
+                found = True
+                break
+            except FileNotFoundError:
+                continue
+        if not found:
+            raise Exception("Impossible to find {}".format(filename))
+
+
+    def get_string_table_name(self):
+        return "string_table_for_" + self.lang_code
+
+    def get_string_table(self):
+        table_entries = ",\n  ".join(self.get_string_table_entries())
+        return expand_cxx_template(string_table_cxx_template,
+                    TABLE_NAME=self.get_string_table_name(),
+                    TABLE_ENTRIES=table_entries)
+
+    def get_string_table_entries(self):
+        d = json.loads(self.data)
+        for k in sorted(d.keys()):
+            if k != "@metadata":
+                key_string = cxx_string_literal(k)
+                value_string = cxx_string_literal(d[k])
+                yield '{ ' + key_string + ', ' + value_string + ' }'
+
+    def get_lang_table_entry(self):
+        return expand_cxx_template(lang_table_entry_cxx_template,
+                LANG_STRING_LITERAL=cxx_string_literal(self.lang_code),
+                STRING_TABLE_NAME=self.get_string_table_name())
+
+
+
+def gen_c_file(resources):
+    string_data = []
+    lang_table = []
+    for r in resources:
+        string_data.append(r.get_string_table())
+        lang_table.append(r.get_lang_table_entry())
+
+    return expand_cxx_template(cxxfile_template,
+                STRING_DATA="\n".join(string_data),
+                LANG_TABLE=",\n  ".join(lang_table),
+                LANG_COUNT=len(resources)
+           )
+
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--cxxfile',
+                        required=True,
+                        help='The Cpp file name to generate')
+    parser.add_argument('i18n_resource_file',
+                        help='The list of resources to compile.')
+    args = parser.parse_args()
+
+    base_dir = os.path.dirname(os.path.realpath(args.i18n_resource_file))
+    with open(args.i18n_resource_file, 'r') as f:
+        resources = [Resource([base_dir], filename)
+                        for filename in f.readlines()]
+
+    with open(args.cxxfile, 'w') as f:
+        f.write(gen_c_file(resources))
+

scripts/kiwix-compile-i18n.1

@@ -0,0 +1,18 @@
+.TH KIWIX-COMPILE-I18N "1" "January 2022" "Kiwix" "User Commands"
+.SH NAME
+kiwix-compile-i18n \- helper to compile Kiwix i18n (internationalization) data
+.SH SYNOPSIS
+\fBkiwix\-compile\-i18n\fR [\-h] \-\-cxxfile CXXFILE i18n_resource_file\fR
+.SH DESCRIPTION
+.TP
+i18n_resource_file
+The list of i18n resources to compile.
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+show a help message and exit
+.TP
+\fB\-\-cxxfile\fR CXXFILE
+The Cpp file name to generate
+.TP
+.SH AUTHOR
+Veloman Yunkan <veloman.yunkan@gmail.com>

scripts/kiwix-compile-resources

@@ -102,7 +102,7 @@ class Resource:
 
 
 
-master_c_template = """//This file is automaically generated. Do not modify it.
+master_c_template = """//This file is automatically generated. Do not modify it.
 
 #include <stdlib.h>
 #include <fstream>

scripts/meson.build

@@ -4,3 +4,9 @@ res_compiler = find_program('kiwix-compile-resources')
 install_data(res_compiler.path(), install_dir:get_option('bindir'))
 
 install_man('kiwix-compile-resources.1')
+
+i18n_compiler = find_program('kiwix-compile-i18n')
+
+install_data(i18n_compiler.path(), install_dir:get_option('bindir'))
+
+install_man('kiwix-compile-i18n.1')

src/meson.build

@@ -33,6 +33,7 @@ kiwix_sources = [
   'version.cpp'
 ]
 kiwix_sources += lib_resources
+kiwix_sources += i18n_resources
 
 if host_machine.system() == 'windows'
   kiwix_sources += 'subprocess_windows.cpp'

src/server/i18n.cpp

@@ -36,6 +36,13 @@ const char* I18nStringTable::get(const std::string& key) const
   return found == end ? nullptr : found->value;
 }
 
+namespace i18n
+{
+// this data is generated by the i18n resource compiler
+extern const I18nStringTable stringTables[];
+extern const size_t langCount;
+}
+
 namespace
 {
 
@@ -44,18 +51,12 @@ const I18nString enStrings[] = {
   { "suggest-full-text-search", "containing '{{{SEARCH_TERMS}}}'..."}
 };
 
-#define ARRAY_ELEMENT_COUNT(a) (sizeof(a)/sizeof(a[0]))
-
-const I18nStringTable i18nStringTables[] = {
-  { "en", ARRAY_ELEMENT_COUNT(enStrings), enStrings }
-};
-
 class I18nStringDB
 {
 public: // functions
   I18nStringDB() {
-    for ( size_t i = 0; i < ARRAY_ELEMENT_COUNT(i18nStringTables); ++i ) {
-      const auto& t = i18nStringTables[i];
+    for ( size_t i = 0; i < kiwix::i18n::langCount; ++i ) {
+      const auto& t = kiwix::i18n::stringTables[i];
       lang2TableMap[t.lang] = &t;
     }
   };

static/i18n/en.json

@@ -0,0 +1,8 @@
+{
+	"@metadata": {
+		"authors": [
+		]
+	},
+	"name":"English",
+	"suggest-full-text-search": "containing '{{{SEARCH_TERMS}}}'..."
+}

static/i18n/qqq.json

@@ -0,0 +1,9 @@
+{
+	"@metadata": {
+		"authors": [
+			"Veloman Yunkan"
+		]
+	},
+	"name": "Current language to which the string is being translated to.",
+	"suggest-full-text-search": "Text appearing in the suggestion list that, when selected, runs a full text search instead of the title search"
+}

static/i18n_resources_list.txt

@@ -0,0 +1 @@
+i18n/en.json

static/meson.build

@@ -14,3 +14,18 @@ lib_resources = custom_target('resources',
              '@INPUT@'],
     depend_files: resource_files
 )
+
+i18n_resource_files = run_command(find_program('python3'),
+                    '-c',
+                    'import sys; f=open(sys.argv[1]); print(f.read())',
+                    files('i18n_resources_list.txt')
+                 ).stdout().strip().split('\n')
+
+i18n_resources = custom_target('i18n_resources',
+    input: 'i18n_resources_list.txt',
+    output: ['libkiwix-i18n-resources.cpp'],
+    command:[i18n_compiler,
+             '--cxxfile', '@OUTPUT0@',
+             '@INPUT@'],
+    depend_files: i18n_resource_files
+)