dist-web: options::page names the page (#649 P2)

Author: Sunrisepeak

dist/web.cppm

@@ -1,5 +1,6 @@
 // mcpp.dist.web -- the wasm32-emscripten stem family becomes a static
-// directory a browser can load, with an `index.html` this member writes.
+// directory a browser can load, with a page this member writes (`index.html`
+// unless `options::page` names another).
 //
 // WHY THIS IS NEITHER A RULE NOR A TOOL, AND WHY IT COMPILES NO TRANSLATION
 // UNIT. Same shape `dist/appimage.cppm` and `dist/apple.cppm` already state:
@@ -117,6 +118,14 @@ struct options {
     // `{{title}}` in the template. Empty means `[package] name`.
     std::string title;
 
+    // The page's file name inside the produced directory. Empty means
+    // `index.html`, what a static file server answers for the directory itself.
+    // A bare `*.html` name with no directory component: an Emscripten build
+    // through CMake names the page after the target (`<target>.html`), and a
+    // project that ships such a page keeps its name (#649 P2). A name with a
+    // separator, or without the `.html` extension, is refused at plan time.
+    std::string page;
+
     // Where the produced directory lands. Empty means `<out_dir>/web`.
     std::string output;
     std::string out_dir = std::string(mcpp::out_dir());
@@ -176,6 +185,25 @@ inline std::string target_for(const options& opt) {
     return (n && *n) ? std::string(n) : std::string();
 }
 
+// The page name `options::page` asks for, or the reason it cannot be used.
+// Bare, because the page is written beside the launcher it loads with a
+// relative `<script src>`; a page in a subdirectory would load nothing.
+inline std::expected<std::string, std::string> page_name(const options& opt) {
+    if (opt.page.empty()) return std::string("index.html");
+    const std::string& n = opt.page;
+    if (n.find('/') != std::string::npos || n.find('\\') != std::string::npos)
+        return std::unexpected(std::format(
+            "`options::page` names '{}', which has a directory component; the "
+            "page is written beside `<name>.js`, so it is a bare file name", n));
+    if (n == ".html" || n.size() <= 5 || !n.ends_with(".html"))
+        return std::unexpected(std::format(
+            "`options::page` names '{}', which is not a `*.html` file name", n));
+    if (n.starts_with("."))
+        return std::unexpected(std::format(
+            "`options::page` names '{}', a hidden file a server does not list", n));
+    return n;
+}
+
 inline std::string replace_all_copy(std::string s, std::string_view from, std::string_view to) {
     if (from.empty()) return s;
     std::size_t pos = 0;
@@ -261,6 +289,14 @@ inline plan plan_for(options opt = {}) {
         return p;
     }
 
+    const auto pageFile = page_name(opt);
+    if (!pageFile) {
+        std::cerr << "mcpp.dist.web: " << pageFile.error() << '\n';
+        mcpp::warning(("mcpp.dist.web: " + pageFile.error()).c_str());
+        p.reason = "page name refused";
+        return p;
+    }
+
     if (!opt.template_file.empty()) {
         const std::string tpl =
             (std::filesystem::path(mcpp::manifest_dir()) / opt.template_file).string();
@@ -291,11 +327,14 @@ inline plan plan_for(options opt = {}) {
     const std::string webDir = !opt.output.empty() ? opt.output
                               : (std::filesystem::path(opt.out_dir) / "web").string();
 
+    // The side file carries the page name, so two packs of one program with
+    // different pages do not overwrite each other's rendering; the default
+    // keeps the name 0.11 wrote (`<target>-index.html`).
     const std::string indexSrc =
-        (std::filesystem::path(opt.out_dir) / (target + "-index.html")).string();
+        (std::filesystem::path(opt.out_dir) / (target + "-" + *pageFile)).string();
     if (!write_if_different(indexSrc, templateBytes)) {
         std::cerr << std::format("mcpp.dist.web: cannot write {}", indexSrc) << '\n';
-        p.reason = "cannot write index.html";
+        p.reason = std::format("cannot write {}", *pageFile);
         return p;
     }
 
@@ -363,9 +402,9 @@ inline plan plan_for(options opt = {}) {
     page.role        = "artifact";
     page.description = "INDEX.HTML";
     page.argv    = { "${mcpp.self}", "stage", "--verify", "content", "--output",
-                     webDir + "/index.html", indexSrc };
+                     webDir + "/" + *pageFile, indexSrc };
     page.inputs  = { indexSrc };
-    page.outputs = { webDir + "/index.html" };
+    page.outputs = { webDir + "/" + *pageFile };
     p.steps.push_back(std::move(page));
 
     p.applies = true;

tests/web-consumer/check-web-plan.sh

@@ -73,5 +73,32 @@ out=$(node "$WEB/web-consumer.js")
 [ "$out" = "1-2-3" ] || fail "node did not print 1-2-3 (got: $out)"
 echo "ok: node $WEB/web-consumer.js prints 1-2-3"
 
+echo "== options::page names the page, and refuses a name that is not a bare *.html file =="
+# A copy of this fixture beside it, so its path dependency on the collection
+# (`../..`) still resolves; the copy's build program sets `options::page`.
+PAGE_FIXTURE="../.web-consumer-page"
+rm -rf "$PAGE_FIXTURE"
+mkdir -p "$PAGE_FIXTURE"
+cp -r mcpp.toml build.mcpp src "$PAGE_FIXTURE"/
+sed -i.bak 's|    opt.target = "web-consumer";|    opt.target = "web-consumer";\n    opt.page   = "web-consumer.html";|' "$PAGE_FIXTURE/build.mcpp"
+grep -q 'opt.page   = "web-consumer.html"' "$PAGE_FIXTURE/build.mcpp" \
+    || fail "the named-page fixture was not written" "$PAGE_FIXTURE/build.mcpp"
+( cd "$PAGE_FIXTURE" && "$MCPP" pack --format web --target wasm32-emscripten > pack.log 2>&1 ) \
+    || fail "mcpp pack --format web with options::page failed" "$PAGE_FIXTURE/pack.log"
+PWEB=$(find "$PAGE_FIXTURE/target" -type d -name web | head -1)
+[ -f "$PWEB/web-consumer.html" ] || fail "options::page = web-consumer.html produced no such page" "$PAGE_FIXTURE/pack.log"
+[ -e "$PWEB/index.html" ] && fail "options::page named another page, and index.html was written as well"
+grep -q 'web-consumer.js' "$PWEB/web-consumer.html" || fail "the named page does not load the launcher" "$PWEB/web-consumer.html"
+echo "ok: options::page = web-consumer.html writes that page and no index.html"
+
+sed -i.bak 's|    opt.page   = "web-consumer.html";|    opt.page   = "pages/web-consumer.html";|' "$PAGE_FIXTURE/build.mcpp"
+if ( cd "$PAGE_FIXTURE" && "$MCPP" pack --format web --target wasm32-emscripten > refuse.log 2>&1 ); then
+    fail "options::page = pages/web-consumer.html was accepted" "$PAGE_FIXTURE/refuse.log"
+fi
+grep -q "has a directory component" "$PAGE_FIXTURE/refuse.log" \
+    || fail "the refusal does not say why the page name was refused" "$PAGE_FIXTURE/refuse.log"
+echo "ok: a page name with a directory component is refused, and the refusal says why"
+rm -rf "$PAGE_FIXTURE"
+
 rm -f build.log pack.log
-echo "PASS: dist-web produces a static directory, node runs it, 1-2-3"
+echo "PASS: dist-web produces a static directory, node runs it, 1-2-3; options::page names the page"