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{ "id": 24354, "url": "https://patchwork.libcamera.org/api/patches/24354/?format=api", "web_url": "https://patchwork.libcamera.org/patch/24354/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20250912142915.53949-4-mzamazal@redhat.com>", "date": "2025-09-12T14:29:04", "name": "[v18,03/12] config: Add configuration retrieval helpers", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": false, "hash": "f40054046bb58923283991f941f6b401c15ba3ae", "submitter": { "id": 177, "url": "https://patchwork.libcamera.org/api/people/177/?format=api", "name": "Milan Zamazal", "email": "mzamazal@redhat.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/24354/mbox/", "series": [ { "id": 5441, "url": "https://patchwork.libcamera.org/api/series/5441/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5441", "date": "2025-09-12T14:29:01", "name": "Add global configuration file", "version": 18, "mbox": "https://patchwork.libcamera.org/series/5441/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/24354/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/24354/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "X-Original-To": "parsemail@patchwork.libcamera.org", "Delivered-To": "parsemail@patchwork.libcamera.org", "Received": [ "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id B24F8BDB13\n\tfor <parsemail@patchwork.libcamera.org>;\n\tFri, 12 Sep 2025 14:29:40 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 70DEF69371;\n\tFri, 12 Sep 2025 16:29:40 +0200 (CEST)", "from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 60E136936A\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tFri, 12 Sep 2025 16:29:39 +0200 (CEST)", "from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com\n\t(ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63])\n\tby relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n\tcipher=TLS_AES_256_GCM_SHA384) id us-mta-205-A0MlOgBPOfCU-IG1PwhdHg-1;\n\tFri, 12 Sep 2025 10:29:34 -0400", "from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com\n\t(mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com\n\t[10.30.177.93])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\tkey-exchange X25519 server-signature RSA-PSS (2048 bits)\n\tserver-digest SHA256) (No client certificate requested)\n\tby mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix)\n\twith ESMTPS id 8B1701944F05; Fri, 12 Sep 2025 14:29:32 +0000 (UTC)", "from mzamazal-thinkpadp1gen7.tpbc.com (unknown [10.45.224.48])\n\tby mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix)\n\twith ESMTP id 2A29E1800446; Fri, 12 Sep 2025 14:29:29 +0000 (UTC)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=redhat.com header.i=@redhat.com\n\theader.b=\"BWusSPGZ\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n\ts=mimecast20190719; t=1757687378;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\tto:to:cc:cc:mime-version:mime-version:content-type:content-type:\n\tcontent-transfer-encoding:content-transfer-encoding:\n\tin-reply-to:in-reply-to:references:references;\n\tbh=2m9iUlP190SfPKl5qDCukWkFc1J1mmvShgqxLKHzFY0=;\n\tb=BWusSPGZnMUoT/c0VEcUdvo9tiuYifigztsiMY99BI8/aoqufPvOCdadgOu3m596nhhKHG\n\t/wPW7b0cpUC9cuOozs4ZL3bpiuTTcPPjYuMz0SUnlluK10XA20FA8t3y9P2UnD4vfwm8+h\n\tb0/ZyMWB2ra+7ZBNWDWyXzeuq5RkLcc=", "X-MC-Unique": "A0MlOgBPOfCU-IG1PwhdHg-1", "X-Mimecast-MFC-AGG-ID": "A0MlOgBPOfCU-IG1PwhdHg_1757687372", "From": "Milan Zamazal <mzamazal@redhat.com>", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Milan Zamazal <mzamazal@redhat.com>, Kieran Bingham\n\t<kieran.bingham@ideasonboard.com>, =?utf-8?q?Barnab=C3=A1s_P=C5=91cze?=\n\t<barnabas.pocze@ideasonboard.com>, Laurent Pinchart\n\t<laurent.pinchart@ideasonboard.com>, Paul Elder\n\t<paul.elder@ideasonboard.com>", "Subject": "[PATCH v18 03/12] config: Add configuration retrieval helpers", "Date": "Fri, 12 Sep 2025 16:29:04 +0200", "Message-ID": "<20250912142915.53949-4-mzamazal@redhat.com>", "In-Reply-To": "<20250912142915.53949-1-mzamazal@redhat.com>", "References": "<20250912142915.53949-1-mzamazal@redhat.com>", "MIME-Version": "1.0", "X-Scanned-By": "MIMEDefang 3.4.1 on 10.30.177.93", "X-Mimecast-Spam-Score": "0", "X-Mimecast-MFC-PROC-ID": "7apG6WGQCF-JikKl9aIEiMBi25cDjei7FR7bJUTSr4U_1757687372", "X-Mimecast-Originator": "redhat.com", "Content-Transfer-Encoding": "8bit", "content-type": "text/plain; charset=\"US-ASCII\"; x-default=true", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "Let's add some helpers to make accessing simple configuration values\nsimpler. The helpers are used in the followup patches.\n\nGlobalConfiguration::option ensures that no value is returned rather\nthan a value of YamlObject::empty.\n\nReviewed-by: Paul Elder <paul.elder@ideasonboard.com>\nSigned-off-by: Milan Zamazal <mzamazal@redhat.com>\n---\n .../libcamera/internal/global_configuration.h | 28 ++++++\n src/libcamera/global_configuration.cpp | 99 +++++++++++++++++++\n 2 files changed, 127 insertions(+)", "diff": "diff --git a/include/libcamera/internal/global_configuration.h b/include/libcamera/internal/global_configuration.h\nindex f695498c4..8d09517ed 100644\n--- a/include/libcamera/internal/global_configuration.h\n+++ b/include/libcamera/internal/global_configuration.h\n@@ -8,6 +8,11 @@\n #pragma once\n \n #include <filesystem>\n+#include <optional>\n+#include <string>\n+#include <string_view>\n+\n+#include <libcamera/base/utils.h>\n \n #include \"libcamera/internal/yaml_parser.h\"\n \n@@ -23,6 +28,29 @@ public:\n \tunsigned int version() const;\n \tConfiguration configuration() const;\n \n+\ttemplate<typename T>\n+\tstd::optional<T> option(\n+\t\tconst std::initializer_list<std::string_view> confPath) const\n+\t{\n+\t\tconst YamlObject *c = &configuration();\n+\t\tfor (auto part : confPath) {\n+\t\t\tc = &(*c)[part];\n+\t\t\tif (!*c)\n+\t\t\t\treturn {};\n+\t\t}\n+\t\treturn c->get<T>();\n+\t}\n+\n+\tstd::optional<std::vector<std::string>> listOption(\n+\t\tconst std::initializer_list<std::string_view> confPath) const;\n+\tstd::optional<std::string> envOption(\n+\t\tconst char *const envVariable,\n+\t\tconst std::initializer_list<std::string_view> confPath) const;\n+\tstd::optional<std::vector<std::string>> envListOption(\n+\t\tconst char *const envVariable,\n+\t\tconst std::initializer_list<std::string_view> confPath,\n+\t\tconst std::string delimiter = \":\") const;\n+\n private:\n \tbool loadFile(const std::filesystem::path &fileName);\n \tvoid load();\ndiff --git a/src/libcamera/global_configuration.cpp b/src/libcamera/global_configuration.cpp\nindex d02668111..592edcf30 100644\n--- a/src/libcamera/global_configuration.cpp\n+++ b/src/libcamera/global_configuration.cpp\n@@ -8,8 +8,12 @@\n #include \"libcamera/internal/global_configuration.h\"\n \n #include <filesystem>\n+#include <memory>\n+#include <optional>\n+#include <string>\n #include <string_view>\n #include <sys/types.h>\n+#include <vector>\n \n #include <libcamera/base/file.h>\n #include <libcamera/base/log.h>\n@@ -43,6 +47,12 @@ LOG_DEFINE_CATEGORY(Configuration)\n * If the first found configuration file cannot be opened or parsed, an error is\n * reported and no configuration file is used. This is to prevent libcamera from\n * using an unintended configuration file.\n+ *\n+ * The configuration can be accessed using the provided helpers. Namely\n+ * GlobalConfiguration::option(), GlobalConfiguration::envOption(),\n+ * GlobalConfiguration::listOption(), and GlobalConfiguration::envListOption()\n+ * to access individual options, or GlobalConfiguration::configuration() to\n+ * access the whole configuration.\n */\n \n bool GlobalConfiguration::loadFile(const std::filesystem::path &fileName)\n@@ -110,6 +120,95 @@ GlobalConfiguration::GlobalConfiguration()\n * the underlying type.\n */\n \n+/**\n+ * \\fn std::optional<T> GlobalConfiguration::option(const std::initializer_list<std::string_view> &confPath) const\n+ * \\brief Return value of the configuration option identified by \\a confPath\n+ * \\param[in] confPath Sequence of the YAML section names (excluding\n+ * `configuration') leading to the requested option\n+ * \\return The value of the configuration item corresponding to \\a confPath if\n+ * it exists in the configuration file, or no value otherwise\n+ */\n+\n+/**\n+ * \\brief Return values of the configuration option identified by \\a confPath\n+ * \\tparam T The type of the retrieved configuration value\n+ * \\param[in] confPath Sequence of the YAML section names (excluding\n+ * `configuration') leading to the requested list option, separated by dots\n+ * \\return A vector of strings or no value if not found\n+ */\n+std::optional<std::vector<std::string>> GlobalConfiguration::listOption(\n+\tconst std::initializer_list<std::string_view> confPath) const\n+{\n+\tconst YamlObject *c = &configuration();\n+\tfor (auto part : confPath) {\n+\t\tc = &(*c)[part];\n+\t\tif (!*c)\n+\t\t\treturn {};\n+\t}\n+\treturn c->getList<std::string>();\n+}\n+\n+/**\n+ * \\brief Return value of environment variable with a fallback on the configuration file\n+ * \\param[in] envVariable Environment variable to get the value from\n+ * \\param[in] confPath The sequence of YAML section names to fall back on when\n+ * \\a envVariable is unavailable\n+ *\n+ * This helper looks first at the given environment variable and if it is\n+ * defined then it returns its value (even if it is empty). Otherwise it looks\n+ * for \\a confPath the same way as in GlobalConfiguration::option. Only string\n+ * values are supported.\n+ *\n+ * \\note Support for using environment variables to configure libcamera behavior\n+ * is provided here mostly for backward compatibility reasons. Introducing new\n+ * configuration environment variables is discouraged.\n+ *\n+ * \\return The value retrieved from the given environment if it is set,\n+ * otherwise the value from the configuration file if it exists, or no value if\n+ * it does not\n+ */\n+std::optional<std::string> GlobalConfiguration::envOption(\n+\tconst char *envVariable,\n+\tconst std::initializer_list<std::string_view> confPath) const\n+{\n+\tconst char *envValue = utils::secure_getenv(envVariable);\n+\tif (envValue)\n+\t\treturn std::optional{ std::string{ envValue } };\n+\treturn option<std::string>(confPath);\n+}\n+\n+/**\n+ * \\brief Return values of the configuration option from a file or environment\n+ * \\param[in] envVariable Environment variable to get the value from\n+ * \\param[in] confPath The same as in GlobalConfiguration::option\n+ * \\param[in] delimiter Items separator in the environment variable\n+ *\n+ * This helper looks first at the given environment variable and if it is\n+ * defined (even if it is empty) then it splits its value by semicolons and\n+ * returns the resulting list of strings. Otherwise it looks for \\a confPath the\n+ * same way as in GlobalConfiguration::option, value of which must be a list of\n+ * strings.\n+ *\n+ * \\note Support for using environment variables to configure libcamera behavior\n+ * is provided here mostly for backward compatibility reasons. Introducing new\n+ * configuration environment variables is discouraged.\n+ *\n+ * \\return A vector of strings retrieved from the given environment option or\n+ * configuration file or no value if not found; the vector may be empty\n+ */\n+std::optional<std::vector<std::string>> GlobalConfiguration::envListOption(\n+\tconst char *const envVariable,\n+\tconst std::initializer_list<std::string_view> confPath,\n+\tconst std::string delimiter) const\n+{\n+\tconst char *envValue = utils::secure_getenv(envVariable);\n+\tif (envValue) {\n+\t\tauto items = utils::split(envValue, delimiter);\n+\t\treturn std::vector<std::string>(items.begin(), items.end());\n+\t}\n+\treturn listOption(confPath);\n+}\n+\n /**\n * \\brief Return configuration version\n *\n", "prefixes": [ "v18", "03/12" ] }