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package main

import (
	"crypto/sha256"
	"fmt"
	"log"
	"net/http"
	"strings"

	"github.com/gorilla/mux"
)

func apiErrCheck(err error, r *http.Request) {
	if err != nil {
		uip := getIPFromCtx(r.Context())
		log.Printf("*** %v :: %v %v :: %v\n", uip, r.Method, r.URL, err.Error())
	}
}

// Takes the output of queries and formats it for
// an HTTP response. Iterates over the string slice,
// appending each entry to a byte slice, and adding
// newlines where appropriate.
func parseQueryOut(out []string) []byte {
	var data []byte

	for i, e := range out {
		data = append(data, []byte(e)...)

		if !strings.HasSuffix(e, "\n") && i != len(out)-1 {
			data = append(data, byte('\n'))
		}
	}

	return data
}

// Removes duplicate statuses from query output
func uniq(str []string) []string {
	keys := make(map[string]bool)
	out := []string{}
	for _, e := range str {
		if _, ok := keys[e]; !ok {
			keys[e] = true
			out = append(out, e)
		}
	}
	return out
}

// apiUserQuery is called via apiEndpointHandler when
// the endpoint is "users" and r.FormValue("q") is not empty.
// It queries the registry cache for users or user URLs
// matching the term supplied via r.FormValue("q")
func apiEndpointQuery(w http.ResponseWriter, r *http.Request) error {
	query := r.FormValue("q")
	urls := r.FormValue("url")
	var out []string
	var err error

	vars := mux.Vars(r)
	endpoint := vars["endpoint"]

	// Handle user URL queries first, then nickname queries.
	// Concatenate both outputs if they're both set.
	// Also handle mention queries and status queries.
	// If we made it this far and 'default' is matched,
	// something went very wrong.
	switch endpoint {
	case "users":
		var out2 []string
		if query != "" {
			out, err = twtxtCache.QueryUser(query)
			apiErrCheck(err, r)
		}
		if urls != "" {
			out2, err = twtxtCache.QueryUser(urls)
			apiErrCheck(err, r)
		}

		out = append(out, out2...)
		out = uniq(out)

	case "mentions":
		if urls == "" {
			return fmt.Errorf("missing URL in mention query")
		}
		urls += ">"
		out, err = twtxtCache.QueryInStatus(urls)
		apiErrCheck(err, r)

	case "tweets":
		query = strings.ToLower(query)
		out, err = twtxtCache.QueryInStatus(query)
		apiErrCheck(err, r)

		query = strings.Title(query)
		out2, err := twtxtCache.QueryInStatus(query)
		apiErrCheck(err, r)

		query = strings.ToUpper(query)
		out3, err := twtxtCache.QueryInStatus(query)
		apiErrCheck(err, r)

		out = append(out, out2...)
		out = append(out, out3...)
		out = uniq(out)

	default:
		return fmt.Errorf("endpoint query, no cases match")
	}

	data := parseQueryOut(out)

	etag := fmt.Sprintf("%x", sha256.Sum256(data))
	w.Header().Set("ETag", etag)
	w.Header().Set("Content-Type", txtutf8)

	_, err = w.Write(data)

	return err
}
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## compute the factorial of 5, and print the result
#
# To run:
#   $ ./bootstrap translate init.linux 0*.subx apps/factorial.subx -o apps/factorial
#   $ ./bootstrap run apps/factorial
# Expected result:
#   $ echo $?
#   120
#
# You can also run the automated test suite:
#   $ ./bootstrap run apps/factorial test
# Expected output:
#   ........
# Every '.' indicates a passing test. Failing tests get a 'F'.

== code
#   instruction                     effective address                                                   register    displacement    immediate
# . op          subop               mod             rm32          base        index         scale       r32
# . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes

Entry:  # run tests if necessary, compute `factorial(5)` if not
    # . prologue
    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp

    # initialize heap
    # . Heap = new-segment(Heap-size)
    # . . push args
    68/push  Heap/imm32
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Heap-size/disp32                  # push *Heap-size
    # . . call
    e8/call  new-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp

    # - if argc > 1 and argv[1] == "test", then return run_tests()
    # if (argc <= 1) goto run-main
    81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0/disp8         1/imm32           # compare *ebp
    7e/jump-if-<=  $run-main/disp8
    # if (!kernel-string-equal?(argv[1], "test")) goto run-main
    # . eax = kernel-string-equal?(argv[1], "test")
    # . . push args
    68/push  "test"/imm32
    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
    # . . call
    e8/call  kernel-string-equal?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
    # . if (eax == false) goto run-main
    3d/compare-eax-and  0/imm32/false
    74/jump-if-=  $run-main/disp8
    # run-tests()
    e8/call  run-tests/disp32
    # syscall(exit, *Num-test-failures)
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/ebx   Num-test-failures/disp32          # copy *Num-test-failures to ebx
    eb/jump  $main:end/disp8
$run-main:
    # - otherwise print factorial(5)
    # eax = factorial(5)
    # . . push args
    68/push  5/imm32
    # . . call
    e8/call  factorial/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
    # var buffer/ecx: (stream byte 10)  # number of decimal digits a 32-bit number can have
    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               0xa/imm32         # subtract from esp
    68/push  0xa/imm32/decimal-digits-in-32bit-number
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
    # write-int32-decimal(buffer, eax)
    # . . push args
    50/push-eax
    51/push-ecx
    # . . call
    e8/call  write-int32-decimal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
    # write-stream(stderr, buffer)
    # . . push args
    51/push-ecx
    68/push  2/imm32/stderr
    # . . call
    e8/call  write-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
    # write(stderr, Newline)
    # . . push args
    68/push  Newline/imm32
    68/push  2/imm32/stderr
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
    # syscall(exit, eax)
    89/copy                         3/mod/direct    3/rm32/ebx    .           .             .           0/r32/eax   .               .                 # copy eax to ebx
$main:end:
    e8/call  syscall_exit/disp32

factorial:  # n: int -> int/eax
    # . prologue
    55/push-ebp
    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
    53/push-ebx
    # if (n <= 1) return 1
    b8/copy-to-eax  1/imm32
    81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         1/imm32           # compare *(ebp+8)
    7e/jump-if-<=  $factorial:end/disp8
    # var ebx: int = n-1
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         3/r32/ebx   8/disp8         .                 # copy *(ebp+8) to ebx
    4b/decrement-ebx
    # var eax: int = factorial(n-1)
    # . . push args
    53/push-ebx
    # . . call
    e8/call  factorial/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
    # return n * factorial(n-1)
    f7          4/subop/multiply    1/mod/*+disp8   5/rm32/ebp    .           .                                     8/disp8         .                 # multiply *(ebp+8) into eax
    # TODO: check for overflow
$factorial:end:
    # . epilogue
    5b/pop-to-ebx
    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
    5d/pop-to-ebp
    c3/return

test-factorial:
    # factorial(5)
    # . . push args
    68/push  5/imm32
    # . . call
    e8/call  factorial/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
    # check-ints-equal(eax, 120, msg)
    # . . push args
    68/push  "F - test-factorial"/imm32
    68/push  0x78/imm32/expected-120
    50/push-eax
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
    # end
    c3/return

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