Port fs.find to CraftOS

Also add support for "?" style wildcards.

Closes #1455.

projects/core/src/main/java/dan200/computercraft/core/apis/FSAPI.java

@@ -443,28 +443,6 @@ public class FSAPI implements ILuaAPI {
         }
     }
 
-    /**
-     * Searches for files matching a string with wildcards.
-     * <p>
-     * This string is formatted like a normal path string, but can include any
-     * number of wildcards ({@code *}) to look for files matching anything.
-     * For example, <code>rom/&#42;/command*</code> will look for any path starting with
-     * {@code command} inside any subdirectory of {@code /rom}.
-     *
-     * @param path The wildcard-qualified path to search for.
-     * @return A list of paths that match the search string.
-     * @throws LuaException If the path doesn't exist.
-     * @cc.since 1.6
-     */
-    @LuaFunction
-    public final String[] find(String path) throws LuaException {
-        try (var ignored = environment.time(Metrics.FS_OPS)) {
-            return getFileSystem().find(path);
-        } catch (FileSystemException e) {
-            throw new LuaException(e.getMessage());
-        }
-    }
-
     /**
      * Returns the capacity of the drive the path is located on.
      *

projects/core/src/main/java/dan200/computercraft/core/filesystem/FileSystem.java

@@ -166,47 +166,6 @@ public class FileSystem {
         return array;
     }
 
-    private void findIn(String dir, List<String> matches, Pattern wildPattern) throws FileSystemException {
-        var list = list(dir);
-        for (var entry : list) {
-            var entryPath = dir.isEmpty() ? entry : dir + "/" + entry;
-            if (wildPattern.matcher(entryPath).matches()) {
-                matches.add(entryPath);
-            }
-            if (isDir(entryPath)) {
-                findIn(entryPath, matches, wildPattern);
-            }
-        }
-    }
-
-    public synchronized String[] find(String wildPath) throws FileSystemException {
-        // Match all the files on the system
-        wildPath = sanitizePath(wildPath, true);
-
-        // If we don't have a wildcard at all just check the file exists
-        var starIndex = wildPath.indexOf('*');
-        if (starIndex == -1) {
-            return exists(wildPath) ? new String[]{ wildPath } : new String[0];
-        }
-
-        // Find the all non-wildcarded directories. For instance foo/bar/baz* -> foo/bar
-        var prevDir = wildPath.substring(0, starIndex).lastIndexOf('/');
-        var startDir = prevDir == -1 ? "" : wildPath.substring(0, prevDir);
-
-        // If this isn't a directory then just abort
-        if (!isDir(startDir)) return new String[0];
-
-        // Scan as normal, starting from this directory
-        var wildPattern = Pattern.compile("^\\Q" + wildPath.replaceAll("\\*", "\\\\E[^\\\\/]*\\\\Q") + "\\E$");
-        List<String> matches = new ArrayList<>();
-        findIn(startDir, matches, wildPattern);
-
-        // Return matches
-        var array = new String[matches.size()];
-        matches.toArray(array);
-        return array;
-    }
-
     public synchronized boolean exists(String path) throws FileSystemException {
         path = sanitizePath(path);
         var mount = getMount(path);
@@ -400,21 +359,20 @@ public class FileSystem {
 
     private static final Pattern threeDotsPattern = Pattern.compile("^\\.{3,}$");
 
+    // IMPORTANT: Both arrays are sorted by ASCII value.
+    private static final char[] specialChars = new char[]{ '"', '*', ':', '<', '>', '?', '|' };
+    private static final char[] specialCharsAllowWildcards = new char[]{ '"', ':', '<', '>', '|' };
+
     public static String sanitizePath(String path, boolean allowWildcards) {
         // Allow windowsy slashes
         path = path.replace('\\', '/');
 
         // Clean the path or illegal characters.
-        final var specialChars = new char[]{
-            '"', ':', '<', '>', '?', '|', // Sorted by ascii value (important)
-        };
-
         var cleanName = new StringBuilder();
+        var allowedChars = allowWildcards ? specialCharsAllowWildcards : specialChars;
         for (var i = 0; i < path.length(); i++) {
             var c = path.charAt(i);
-            if (c >= 32 && Arrays.binarySearch(specialChars, c) < 0 && (allowWildcards || c != '*')) {
-                cleanName.append(c);
-            }
+            if (c >= 32 && Arrays.binarySearch(allowedChars, c) < 0) cleanName.append(c);
         }
         path = cleanName.toString();
 

projects/core/src/main/resources/data/computercraft/lua/rom/apis/fs.lua

@@ -133,6 +133,93 @@ function fs.complete(sPath, sLocation, bIncludeFiles, bIncludeDirs)
     return {}
 end
 
+local function find_aux(path, parts, i, out)
+    local part = parts[i]
+    if not part then
+        -- If we're at the end of the pattern, ensure our path exists and append it.
+        if fs.exists(path) then out[#out + 1] = path end
+    elseif part.exact then
+        -- If we're an exact match, just recurse into this directory.
+        return find_aux(fs.combine(path, part.contents), parts, i + 1, out)
+    else
+        -- Otherwise we're a pattern. Check we're a directory, then recurse into each
+        -- matching file.
+        if not fs.isDir(path) then return end
+
+        local files = fs.list(path)
+        for j = 1, #files do
+            local file = files[j]
+            if file:find(part.contents) then find_aux(fs.combine(path, file), parts, i + 1, out) end
+        end
+    end
+end
+
+local find_escape = {
+    -- Escape standard Lua pattern characters
+    ["^"] = "%^", ["$"] = "%$", ["("] = "%(", [")"] = "%)", ["%"] = "%%",
+    ["."] = "%.", ["["] = "%[", ["]"] = "%]", ["+"] = "%+", ["-"] = "%-",
+    -- Aside from our wildcards.
+    ["*"] = ".*",
+    ["?"] = ".",
+}
+
+--[[- Searches for files matching a string with wildcards.
+
+This string looks like a normal path string, but can include wildcards, which
+can match multiple paths:
+
+ - "?" matches any single character in a file name.
+ - "*" matches any number of characters.
+
+For example, `rom/*/command*` will look for any path starting with `command`
+inside any subdirectory of `/rom`.
+
+Note that these wildcards match a single segment of the path. For instance
+`rom/*.lua` will include `rom/startup.lua` but _not_ include `rom/programs/list.lua`.
+
+@tparam string path The wildcard-qualified path to search for.
+@treturn { string... } A list of paths that match the search string.
+@throws If the supplied path was invalid.
+@since 1.6
+@changed 1.106.0 Added support for the `?` wildcard.
+
+@usage List all Markdown files in the help folder
+
+    fs.find("rom/help/*.md")
+]]
+function fs.find(pattern)
+    expect(1, pattern, "string")
+
+    pattern = fs.combine(pattern) -- Normalise the path, removing ".."s.
+
+    -- If the pattern is trying to search outside the computer root, just abort.
+    -- This will fail later on anyway.
+    if pattern == ".." or pattern:sub(1, 3) == "../" then
+        error("/" .. pattern .. ": Invalid Path", 2)
+    end
+
+    -- If we've no wildcards, just check the file exists.
+    if not pattern:find("[*?]") then
+        if fs.exists(pattern) then return { pattern } else return {} end
+    end
+
+    local parts = {}
+    for part in pattern:gmatch("[^/]+") do
+        if part:find("[*?]") then
+            parts[#parts + 1] = {
+                exact = false,
+                contents = "^" .. part:gsub(".", find_escape) .. "$",
+            }
+        else
+            parts[#parts + 1] = { exact = true, contents = part }
+        end
+    end
+
+    local out = {}
+    find_aux("", parts, 1, out)
+    return out
+end
+
 --- Returns true if a path is mounted to the parent filesystem.
 --
 -- The root filesystem "/" is considered a mount, along with disk folders and

projects/core/src/test/resources/test-rom/spec/apis/fs_spec.lua

@@ -87,6 +87,53 @@ describe("The fs library", function()
         end)
     end)
 
+    describe("fs.find", function()
+        it("fails on invalid paths", function()
+            expect.error(fs.find, ".."):eq("/..: Invalid Path")
+            expect.error(fs.find, "../foo/bar"):eq("/../foo/bar: Invalid Path")
+        end)
+
+        it("returns nothing on non-existent files", function()
+            expect(fs.find("no/such/file")):same {}
+            expect(fs.find("no/such/*")):same {}
+            expect(fs.find("no/*/file")):same {}
+        end)
+
+        it("returns a single file", function()
+            expect(fs.find("rom")):same { "rom" }
+            expect(fs.find("rom/motd.txt")):same { "rom/motd.txt" }
+        end)
+
+        it("supports the '*' wildcard", function()
+            expect(fs.find("rom/*")):same {
+                "rom/apis",
+                "rom/autorun",
+                "rom/help",
+                "rom/modules",
+                "rom/motd.txt",
+                "rom/programs",
+                "rom/startup.lua",
+            }
+            expect(fs.find("rom/*/command")):same {
+                "rom/apis/command",
+                "rom/modules/command",
+                "rom/programs/command",
+            }
+
+            expect(fs.find("rom/*/lua*")):same {
+                "rom/help/lua.txt",
+                "rom/programs/lua.lua",
+            }
+        end)
+
+        it("supports the '?' wildcard", function()
+            expect(fs.find("rom/programs/mo??.lua")):same {
+                "rom/programs/motd.lua",
+                "rom/programs/move.lua",
+            }
+        end)
+    end)
+
     describe("fs.combine", function()
         it("removes . and ..", function()
             expect(fs.combine("./a/b")):eq("a/b")