[lnav -i] write file to install to temp file

Related to #1240

src/base/fs_util.cc

@@ -117,9 +117,12 @@ read_file(const ghc::filesystem::path& path)
     }
 }
 
-Result<void, std::string>
-write_file(const ghc::filesystem::path& path, const string_fragment& content)
+Result<write_file_result, std::string>
+write_file(const ghc::filesystem::path& path,
+           const string_fragment& content,
+           std::set<write_file_options> options)
 {
+    write_file_result retval;
     auto tmp_pattern = path;
     tmp_pattern += ".XXXXXX";
 
@@ -138,7 +141,25 @@ write_file(const ghc::filesystem::path& path, const string_fragment& content)
                                bytes_written,
                                content.length()));
     }
+
     std::error_code ec;
+    if (options.count(write_file_options::backup_existing)) {
+        if (ghc::filesystem::exists(path, ec)) {
+            auto backup_path = path;
+
+            backup_path += ".bak";
+            ghc::filesystem::rename(path, backup_path, ec);
+            if (ec) {
+                return Err(
+                    fmt::format(FMT_STRING("unable to backup file {}: {}"),
+                                path.string(),
+                                ec.message()));
+            }
+
+            retval.wfr_backup_path = backup_path;
+        }
+    }
+
     ghc::filesystem::rename(tmp_pair.first, path, ec);
     if (ec) {
         return Err(
@@ -147,7 +168,7 @@ write_file(const ghc::filesystem::path& path, const string_fragment& content)
                         ec.message()));
     }
 
-    return Ok();
+    return Ok(retval);
 }
 
 std::string

src/base/fs_util.hh

@@ -30,6 +30,7 @@
 #ifndef lnav_fs_util_hh
 #define lnav_fs_util_hh
 
+#include <set>
 #include <string>
 #include <vector>
 
@@ -84,8 +85,18 @@ Result<std::pair<ghc::filesystem::path, auto_fd>, std::string> open_temp_file(
 
 Result<std::string, std::string> read_file(const ghc::filesystem::path& path);
 
-Result<void, std::string> write_file(const ghc::filesystem::path& path,
-                                     const string_fragment& content);
+enum class write_file_options {
+    backup_existing,
+};
+
+struct write_file_result {
+    nonstd::optional<ghc::filesystem::path> wfr_backup_path;
+};
+
+Result<write_file_result, std::string> write_file(
+    const ghc::filesystem::path& path,
+    const string_fragment& content,
+    std::set<write_file_options> options = {});
 
 std::string build_path(const std::vector<ghc::filesystem::path>& paths);
 

src/lnav.cc

@@ -2762,45 +2762,64 @@ SELECT tbl_name FROM sqlite_master WHERE sql LIKE 'CREATE VIRTUAL TABLE%'
                                  ? configs_installed_path
                                  : formats_installed_path)
                 / dst_name;
-            auto_fd in_fd, out_fd;
 
-            if ((in_fd = open(file_path.c_str(), O_RDONLY)) == -1) {
-                perror("unable to open file to install");
-            } else if ((out_fd = lnav::filesystem::openp(
-                            dst_path, O_WRONLY | O_CREAT | O_TRUNC, 0644))
-                       == -1)
-            {
-                fprintf(stderr,
-                        "error: unable to open destination: %s -- %s\n",
-                        dst_path.c_str(),
-                        strerror(errno));
-            } else {
-                char buffer[2048];
-                ssize_t rc;
-
-                while ((rc = read(in_fd, buffer, sizeof(buffer))) > 0) {
-                    ssize_t remaining = rc, written;
-
-                    while (remaining > 0) {
-                        written = write(out_fd, buffer, rc);
-                        if (written == -1) {
-                            fprintf(stderr,
-                                    "error: unable to install file "
-                                    "-- %s\n",
-                                    strerror(errno));
-                            exit(EXIT_FAILURE);
-                        }
+            auto read_res = lnav::filesystem::read_file(file_path);
+            if (read_res.isErr()) {
+                auto um = lnav::console::user_message::error(
+                              attr_line_t("cannot read file to install -- ")
+                                  .append(lnav::roles::file(file_path)))
+                              .with_reason(read_res.unwrap());
 
-                        remaining -= written;
-                    }
+                lnav::console::print(stderr, um);
+                return EXIT_FAILURE;
+            }
+
+            auto file_content = read_res.unwrap();
+
+            auto read_dst_res = lnav::filesystem::read_file(dst_path);
+            if (read_dst_res.isOk()) {
+                auto dst_content = read_dst_res.unwrap();
+
+                if (dst_content == file_content) {
+                    auto um = lnav::console::user_message::info(
+                        attr_line_t("file is already installed at -- ")
+                            .append(lnav::roles::file(dst_path)));
+
+                    lnav::console::print(stdout, um);
+
+                    return EXIT_SUCCESS;
                 }
+            }
 
-                lnav::console::print(
-                    stderr,
-                    lnav::console::user_message::ok(
-                        attr_line_t("installed -- ")
-                            .append(lnav::roles::file(dst_path))));
+            auto write_res = lnav::filesystem::write_file(
+                dst_path,
+                file_content,
+                {lnav::filesystem::write_file_options::backup_existing});
+            if (write_res.isErr()) {
+                auto um = lnav::console::user_message::error(
+                              attr_line_t("failed to install file to -- ")
+                                  .append(lnav::roles::file(dst_path)))
+                              .with_reason(write_res.unwrapErr());
+
+                lnav::console::print(stderr, um);
+                return EXIT_FAILURE;
             }
+
+            auto write_file_res = write_res.unwrap();
+            auto um = lnav::console::user_message::ok(
+                attr_line_t("installed -- ")
+                    .append(lnav::roles::file(dst_path)));
+            if (write_file_res.wfr_backup_path) {
+                um.with_note(
+                    attr_line_t("the previously installed ")
+                        .append_quoted(
+                            lnav::roles::file(dst_path.filename().string()))
+                        .append(" was backed up to -- ")
+                        .append(lnav::roles::file(
+                            write_file_res.wfr_backup_path.value().string())));
+            }
+
+            lnav::console::print(stdout, um);
         }
         return EXIT_SUCCESS;
     }

test/expected/expected.am

@@ -278,6 +278,12 @@ EXPECTED_FILES = \
     $(srcdir)/%reldir%/test_events.sh_d9c7907f907b2335e1328b23fdc46d0968a608d9.out \
     $(srcdir)/%reldir%/test_events.sh_ed8dc44add223341c03ccb7b3e18371bdb42b710.err \
     $(srcdir)/%reldir%/test_events.sh_ed8dc44add223341c03ccb7b3e18371bdb42b710.out \
+    $(srcdir)/%reldir%/test_format_installer.sh_1e08efc3b8c7b67d944a1f8c475cd31d98d5b4f6.err \
+    $(srcdir)/%reldir%/test_format_installer.sh_1e08efc3b8c7b67d944a1f8c475cd31d98d5b4f6.out \
+    $(srcdir)/%reldir%/test_format_installer.sh_6cd73153a8990b8ddb8ce489e90ec667a442f7f9.err \
+    $(srcdir)/%reldir%/test_format_installer.sh_6cd73153a8990b8ddb8ce489e90ec667a442f7f9.out \
+    $(srcdir)/%reldir%/test_format_installer.sh_947cbc64a150c7fe2a17e1c7a69e9a932aeaa16b.err \
+    $(srcdir)/%reldir%/test_format_installer.sh_947cbc64a150c7fe2a17e1c7a69e9a932aeaa16b.out \
     $(srcdir)/%reldir%/test_format_loader.sh_15e861d2327512a721fd42ae51dc5427689e0bb6.err \
     $(srcdir)/%reldir%/test_format_loader.sh_15e861d2327512a721fd42ae51dc5427689e0bb6.out \
     $(srcdir)/%reldir%/test_format_loader.sh_5992e2695b7e6cf1f3520dbb87af8fc2b8f27088.err \

test/expected/test_format_installer.sh_1e08efc3b8c7b67d944a1f8c475cd31d98d5b4f6.err

@@ -0,0 +1,2 @@
+✘ error: unable to open configuration file: /non-existent/file
+ reason: No such file or directory

test/expected/test_format_installer.sh_6cd73153a8990b8ddb8ce489e90ec667a442f7f9.out

@@ -0,0 +1,2 @@
+✔ installed -- ../installer-test-home/.lnav/formats/installed/test_log.json
+ = note: the previously installed “test_log.json” was backed up to -- ../installer-test-home/.lnav/formats/installed/test_log.json.bak

test/expected/test_format_installer.sh_947cbc64a150c7fe2a17e1c7a69e9a932aeaa16b.out

@@ -0,0 +1 @@
+ⓘ info: file is already installed at -- ../installer-test-home/.lnav/formats/installed/test_log.json

test/test_format_installer.sh

@@ -8,6 +8,7 @@ rm -rf "${CONFIG_DIR}/.lnav/formats"
 HOME=${CONFIG_DIR}
 unset XDG_CONFIG_HOME
 export HOME
+export YES_COLOR=1
 
 ${lnav_test} -i ${srcdir}/formats/jsontest/format.json
 
@@ -16,6 +17,19 @@ if ! test -f ${CONFIG_DIR}/.lnav/formats/installed/test_log.json; then
     exit 1
 fi
 
+run_cap_test ${lnav_test} -i ${srcdir}/formats/jsontest/format.json
+
+echo corrupt > ${CONFIG_DIR}/.lnav/formats/installed/test_log.json
+
+run_cap_test env TEST_COMMENT='overwrite file' ${lnav_test} -i ${srcdir}/formats/jsontest/format.json
+
+if ! test -f ${CONFIG_DIR}/.lnav/formats/installed/test_log.json.bak; then
+    echo "Format not backed up correctly?"
+    exit 1
+fi
+
+run_cap_test ${lnav_test} -i /non-existent/file
+
 if test x"${TEST_GIT_INSTALL}" = x""; then
     # Hitting the git repos frequently is slow/noisy
     exit 0