From 3ae79d3dfee677477a3437ee4a1517dc8ca3bb16 Mon Sep 17 00:00:00 2001 From: Paul Campbell Date: Thu, 30 Dec 2021 21:03:07 +0000 Subject: [PATCH] Clean error when file not found --- src/main.zig | 74 +++++++++++++++++++++++++++++++++++------ src/test/four-lines.txt | 4 +++ 2 files changed, 68 insertions(+), 10 deletions(-) create mode 100644 src/test/four-lines.txt diff --git a/src/main.zig b/src/main.zig index b434ca4..187a167 100644 --- a/src/main.zig +++ b/src/main.zig @@ -24,8 +24,9 @@ pub fn main() anyerror!void { var fba = heap.FixedBufferAllocator.init(&buffer); const allocator = fba.allocator(); - const config: Config = parseArgs() catch |err| switch (err) { + const config: Config = parseArgs(allocator) catch |err| switch (err) { error.EarlyExit => return, + error.FileNotFound => return, else => @panic("Unknown error"), }; defer config.deinit(); @@ -40,12 +41,14 @@ pub fn main() anyerror!void { } const errors = error { - EarlyExit + EarlyExit, + FileNotFound }; const Config = struct { lines: u32, file: ?fs.File, + line: ?[]const u8 = null, pub fn deinit(self: @This()) void { if (self.file) |f| { @@ -54,12 +57,13 @@ const Config = struct { } }; -fn parseArgs() !Config { +fn parseArgs(allocator: mem.Allocator) !Config { const params = comptime [_]clap.Param(clap.Help) { - clap.parseParam(" The number of lines to skip") catch unreachable, - clap.parseParam("[] The file to read or stdin if not given") catch unreachable, - clap.parseParam("-h, --help Display this help and exit") catch unreachable, - clap.parseParam("-v, --version Display the version") catch unreachable, + clap.parseParam(" The number of lines to skip") catch unreachable, + clap.parseParam("[] The file to read or stdin if not given") catch unreachable, + clap.parseParam("-l, --line Skip until N lines matching this") catch unreachable, + clap.parseParam("-h, --help Display this help and exit") catch unreachable, + clap.parseParam("-v, --version Display the version") catch unreachable, }; var diag = clap.Diagnostic{}; var args = clap.parse(clap.Help, ¶ms, .{ .diagnostic = &diag }) catch |err| { @@ -77,6 +81,10 @@ fn parseArgs() !Config { try clap.help(io.getStdErr().writer(), ¶ms); return error.EarlyExit; } + var line: ?[]const u8 = null; + if (args.option("--line")) |match| { + line = try allocator.dupe(u8, match); + } var n: u32 = 0; var file: ?fs.File = null; @@ -89,11 +97,18 @@ fn parseArgs() !Config { } if (args.positionals().len >= 2) { const filename = args.positionals()[1]; - file = try fs.cwd().openFile(filename, .{ .read = true, .write = false }); + file = fs.cwd().openFile(filename, .{ .read = true, .write = false }) catch |err| switch (err) { + error.FileNotFound => { + try io.getStdErr().writer().print("Error: File not found: {s}\n", .{ filename }); + return err; + }, + else => return err, + }; } return Config { .lines = n, .file = file, + .line = line, }; } @@ -102,8 +117,17 @@ fn dumpInput(config: Config, in: fs.File, out: fs.File, allocator: mem.Allocator const reader = in.reader(); var it: LineIterator = lineIterator(reader, allocator); var c: u32 = 0; - while (c < config.lines) : (c += 1) { + while (c < config.lines) { const line = it.next(); + if (config.line) |match| { + if (line) |memory| { + if (mem.eql(u8, match, memory)) { + c += 1; + } + } + } else { + c += 1; + } if (line) |memory| { allocator.free(memory); } else return; @@ -111,7 +135,7 @@ fn dumpInput(config: Config, in: fs.File, out: fs.File, allocator: mem.Allocator try pumpIterator(&it, writer, allocator); } -test "dumpInput" { +test "dumpInput skip 1 line" { const file = try fs.cwd().openFile("src/test/two-lines.txt", .{ .read = true, .write = false }); defer file.close(); @@ -140,6 +164,36 @@ test "dumpInput" { try testing.expect(eof == null); } +test "dumpInput skip 2 line 'alpha'" { + const file = try fs.cwd().openFile("src/test/four-lines.txt", .{ .read = true, .write = false }); + defer file.close(); + + const tempFile = "zig-cache/test.txt"; + + const output = try fs.cwd().createFile(tempFile, .{}); + defer output.close(); + + const config = Config{ + .lines = 2, + .file = file, + .line = "alpha", + }; + + try dumpInput(config, file, output, testing.allocator); + + const result = try fs.cwd().openFile(tempFile, .{ .read = true }); + defer result.close(); + + var rit = lineIterator(result.reader(), testing.allocator); + + const line1 = rit.next().?; + defer testing.allocator.free(line1); + try testing.expectEqualStrings("gamma", line1); + + const eof = rit.next(); + try testing.expect(eof == null); +} + fn pumpIterator(it: *LineIterator, writer: fs.File.Writer, allocator: mem.Allocator) !void { while (it.next()) |line| { defer allocator.free(line); diff --git a/src/test/four-lines.txt b/src/test/four-lines.txt new file mode 100644 index 0000000..536a7f5 --- /dev/null +++ b/src/test/four-lines.txt @@ -0,0 +1,4 @@ +alpha +beta +alpha +gamma