refactor: make mime-type array inline constexpr (#1872)

* refactor: make mime-type array inline constexpr

* fix: iwyu <iterator> for std::back_inserter

* fix: remove newly-unused variable in mime-types.js

Transmission.xcodeproj/project.pbxproj

@@ -370,7 +370,6 @@
 		C1FEE57A1C3223CC00D62832 /* watchdir.cc in Sources */ = {isa = PBXBuildFile; fileRef = C1FEE5751C3223CC00D62832 /* watchdir.cc */; };
 		C1FEE57B1C3223CC00D62832 /* watchdir.h in Headers */ = {isa = PBXBuildFile; fileRef = C1FEE5761C3223CC00D62832 /* watchdir.h */; };
 		CAB35C64252F6F5E00552A55 /* mime-types.h in Headers */ = {isa = PBXBuildFile; fileRef = CAB35C62252F6F5E00552A55 /* mime-types.h */; };
-		CAB35C65252F6F5E00552A55 /* mime-types.cc in Sources */ = {isa = PBXBuildFile; fileRef = CAB35C63252F6F5E00552A55 /* mime-types.cc */; };
 		E138A9780C04D88F00C5426C /* ProgressGradients.mm in Sources */ = {isa = PBXBuildFile; fileRef = E138A9760C04D88F00C5426C /* ProgressGradients.mm */; };
 		EDBDFA9E25AFCCA60093D9C1 /* evutil_time.c in Sources */ = {isa = PBXBuildFile; fileRef = EDBDFA9D25AFCCA60093D9C1 /* evutil_time.c */; };
 		F63480631E1D7274005B9E09 /* Images.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = F63480621E1D7274005B9E09 /* Images.xcassets */; };
@@ -1031,7 +1030,6 @@
 		C1FEE5751C3223CC00D62832 /* watchdir.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = watchdir.cc; sourceTree = "<group>"; };
 		C1FEE5761C3223CC00D62832 /* watchdir.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = watchdir.h; sourceTree = "<group>"; };
 		CAB35C62252F6F5E00552A55 /* mime-types.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "mime-types.h"; sourceTree = "<group>"; };
-		CAB35C63252F6F5E00552A55 /* mime-types.cc */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = "mime-types.cc"; sourceTree = "<group>"; };
 		E138A9750C04D88F00C5426C /* ProgressGradients.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ProgressGradients.h; sourceTree = "<group>"; };
 		E138A9760C04D88F00C5426C /* ProgressGradients.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = ProgressGradients.mm; sourceTree = "<group>"; };
 		EDBDFA9D25AFCCA60093D9C1 /* evutil_time.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = evutil_time.c; sourceTree = "<group>"; };
@@ -1390,7 +1388,6 @@
 		4D1838DC09DEC04A0047D688 /* libtransmission */ = {
 			isa = PBXGroup;
 			children = (
-				CAB35C63252F6F5E00552A55 /* mime-types.cc */,
 				CAB35C62252F6F5E00552A55 /* mime-types.h */,
 				C1077A4A183EB29600634C22 /* error.cc */,
 				C1077A4B183EB29600634C22 /* error.h */,
@@ -2472,7 +2469,6 @@
 				A201527E0D1C270F0081714F /* torrent-ctor.cc in Sources */,
 				A2D22A130D65EEE700007D5F /* verify.cc in Sources */,
 				4D4ADFC70DA1631500A68297 /* blocklist.cc in Sources */,
-				CAB35C65252F6F5E00552A55 /* mime-types.cc in Sources */,
 				A29DF8B90DB2544C00D04E5A /* resume.cc in Sources */,
 				A2A4E9220DE0F7EB000CE197 /* web.cc in Sources */,
 				A2A4EA0E0DE106EB000CE197 /* ConvertUTF.c in Sources */,

libtransmission/CMakeLists.txt

@@ -33,7 +33,6 @@ set(PROJECT_FILES
   magnet.cc
   makemeta.cc
   metainfo.cc
-  mime-types.cc
   natpmp.cc
   net.cc
   peer-io.cc

libtransmission/mime-types.js

@@ -34,39 +34,32 @@ https.get(url, (res) => {
         }
       }
 
-      const max_suffix_len = suffixes
-        .reduce((acc, [suffix]) => Math.max(acc, suffix.length), 0);
-
       const mime_type_lines = suffixes
         .map(([suffix, mime_type]) => `      { "${suffix}", "${mime_type}" }`)
         .sort()
         .join(',\n');
-      fs.writeFileSync('mime-types.c', `${copyright}
-
-#include "mime-types.h"
-
-struct mime_type_suffix const mime_type_suffixes[MIME_TYPE_SUFFIX_COUNT] =
-{
-${mime_type_lines}
-};
-`);
       fs.writeFileSync('mime-types.h', `${copyright}
 
 #pragma once
 
-#define MIME_TYPE_SUFFIX_MAXLEN ${max_suffix_len}
+#include <array>
-#define MIME_TYPE_SUFFIX_COUNT ${suffixes.length}
+#include <string_view>
 
 struct mime_type_suffix
 {
-    char const* suffix;
+    std::string_view suffix;
-    char const* mime_type;
+    std::string_view mime_type;
 };
 
-extern struct mime_type_suffix const mime_type_suffixes[MIME_TYPE_SUFFIX_COUNT];
+inline auto constexpr mime_type_suffixes = std::array<mime_type_suffix, ${suffixes.length}>
+{{
+${mime_type_lines}
+}};
+
 `);
     } catch (e) {
       console.error(e.message);
     }
   });
 });
+

libtransmission/utils.cc

@@ -25,6 +25,7 @@
 #include <cstring> /* strerror(), memset(), memmem() */
 #include <ctime> /* nanosleep() */
 #include <exception>
+#include <iterator> // std::back_inserter
 #include <set>
 #include <string>
 #include <vector>
@@ -1914,40 +1915,32 @@ void tr_net_init(void)
 
 /// mime-type
 
-static int compareSuffix(void const* va, void const* vb)
+char const* tr_get_mime_type_for_filename(std::string_view filename)
 {
-    auto const* suffix = static_cast<char const*>(va);
+    auto constexpr compare = [](mime_type_suffix const& entry, auto const& suffix)
-    auto const* entry = static_cast<struct mime_type_suffix const*>(vb);
+    {
-    return tr_strcmp0(suffix, entry->suffix);
+        return entry.suffix < suffix;
-}
+    };
-
+
-char const* tr_get_mime_type_for_filename(char const* filename)
+    auto const pos = filename.rfind('.');
-{
+    if (pos != filename.npos)
-    struct mime_type_suffix const* info = nullptr;
+    {
-
+        // make a lowercase copy of the file suffix
-    char const* in = strrchr(filename, '.');
+        filename.remove_prefix(pos + 1);
-    if (in != nullptr)
+        auto suffix_lc = std::string{};
-    {
+        std::transform(
-        ++in; // walk past '.'
+            std::begin(filename),
-        if (strlen(in) <= MIME_TYPE_SUFFIX_MAXLEN)
+            std::end(filename),
-        {
+            std::back_inserter(suffix_lc),
-            char lowercase_suffix[MIME_TYPE_SUFFIX_MAXLEN + 1];
+            [](auto c) { return std::tolower(c); });
-            char* out = lowercase_suffix;
+
-            while (*in != '\0')
+        // find it
-            {
+        auto const it = std::lower_bound(std::begin(mime_type_suffixes), std::end(mime_type_suffixes), suffix_lc, compare);
-                *out++ = (char)tolower((unsigned char)*in++);
+        if (it != std::end(mime_type_suffixes) && suffix_lc == it->suffix)
-            }
+        {
-
+            return std::data(it->mime_type);
-            *out = '\0';
+        }
-
+    }
-            info = static_cast<struct mime_type_suffix const*>(bsearch(
+
-                lowercase_suffix,
+    return nullptr;
-                mime_type_suffixes,
-                TR_N_ELEMENTS(mime_type_suffixes),
-                sizeof(*mime_type_suffixes),
-                compareSuffix));
-        }
-    }
-
-    return info != nullptr ? info->mime_type : nullptr;
 }

libtransmission/utils.h

@@ -11,6 +11,7 @@
 #include <inttypes.h>
 #include <stdarg.h>
 #include <stddef.h> /* size_t */
+#include <string_view>
 #include <time.h> /* time_t */
 #include <vector>
 
@@ -59,7 +60,7 @@ char const* tr_strip_positional_args(char const* fmt);
 
 #define TR_N_ELEMENTS(ary) (sizeof(ary) / sizeof(*(ary)))
 
-char const* tr_get_mime_type_for_filename(char const* filename);
+char const* tr_get_mime_type_for_filename(std::string_view filename);
 
 /**
  * @brief Rich Salz's classic implementation of shell-style pattern matching for ?, \, [], and * characters.